Analogue Equipment Recording Quality ?

first thing i would do is insert edit rather than assemble edit , thereby saving 1/2 generation.( you will need to black the tape you are insert editing onto )

i would also use svhs tapes in svhs deck for mastering to from camera , rather than mastering to umatic.

for copying final copies you can then feed svhs tape from camera to svhs deck for vhs copies.

OK sepulcre...

Why would you...
* insert edit rather than assemble edit ?
* How does this change the amount of generations ?
* Master onto svhs tapes in svhs deck, rather than mastering to umatic.

If I follow your scenario correctly you are doing a live recording to the BVU from the camera so I'm not sure why you need the mixer?

As long as the BVU is in good condition and correctly set-up using this as the Master recorder is the best option when your only other machines are domestic SVHS.

Monitor the output of the UMatic tape and compare it to the output off your dubbed VHS
tapes to determine where your problem lies.

Hi,

A couple of things,

Are you using Y/C between camera/decks/mixer? You should if not.

Its been a long time since I have seen a BVU 800, but remember that they had a damn good picture for U-matic.

Are you are in High band mode?

After recording on the U-matic are the playback pictures good. Is the RF meter pointing at 3?

Umatic SP was better quality and more robust then SVHS, don't have the specs to hand though.

[This message has been edited by GG (edited 04 June 2002).]

quote:Originally posted by malcolm samuels:
OK sepulcre...

Why would you...
* insert edit rather than assemble edit ?
* How does this change the amount of generations ?
* Master onto svhs tapes in svhs deck, rather than mastering to umatic.

1. prerecord nothing onto the svhs tape.rewind tape.
1. a. then use insert edit mode on svhs deck ( should be in manual) and record pictures ontop of black.

2. i was always taught that assemble edit was 1 generationand insert edit was 1/2 generation.

3. i think i misread what you were doing with the camera and recorder.
i assumed that you were recording on camera , making a master onto umatic and duplicating from there to the bvhs tapes.

if however you are not recording using the svhs camcorder then my system won't work.

if you confirm the process exactly then i can relook at the problem, since i personally can see no benefit in not recording to svhs as master, rather than umatic.

Hi sepulcre,

Record nothing???

I think you mean record Black.
Nothing won't work. As I think this Pana mixer has an SPG built in this will provide a good clean Black signal to tape.

There are several reasons for blacking and inserting, ultimatly though it is to lay a consistant control and TC track and correct 8 field sequence so when editing you won't get possible picture disturbance at edit points, inconsistant control track, incorrect colour framing or servo lock etc.

Assemble editing also won't alow you to drop an edit in the middle of your tape without leaving inconsistant control track etc at the end of the edit.

I wouldn't agree that Insert editing gave you a better quality result than Assemble.
Assemble is just a more controlled way of hitting the record button.

As the BVU is an High Band machine it will be superior to SVHS, if it was low band I wouldn't bother and would agree that an SVHS master would be better, but this isn't the case.

rgds

GG

[This message has been edited by GG (edited 04 June 2002).]

GG is correct.

The BVU800 is a Highband Machine which isn't in the same street as SVHS.

Blacking and insert editing or assemble editing will make no difference whatsoever.

However, had the U-Matic been Low Band I would still have chosen it in preference to a domestic S-VHS machine but NOT to an industrial S-VHS (Panasonic AG7500/7600 Series)

I think we should wait for Malcolm to tell us why he needs the mixer because I can't see it adding anything but degredation and maybe we need to remember we're trying to help solve a colleague's problem and not argue amongst ourselves on a topic that some obviously don't understand.

Ok, Thanks you guys, now let me clarify...

The Umatic is Hi Band.
It is a pro deck which has both insert and assemble edit control.
Therefore, in assemble edit, it will control the roll back (pre roll etc) so that it matches up the sync and tc etc, therefore there should be no jumps or disturbance at the point of the AE,
(and this works ok !)

The camcorder is used as a camera only, i.e. no recording on the cam tape is used.
The camera is cabled to the mixer, via an S-Video cable.
The mixer is cabled to the Sony via a composite (RF) cable,
(because that's the standard on Umatics)

The mixer is needed because I am also feeding in a signal from my PC to record Screen Shots.
NB: I'm using a converter to do that, and yes, I know that the quality of the SS will be poor, compared to the original PC SS, so I'll have to live with that.

My problem:
No matter what configuration I use.
(I think I've tried them all, and the above configuration seems the best)
(and should be the best !)
I cannot get what I would consider to be an * [acceptable quality] * of recording, on the VHS dubbed copy, and...

* As my bench mark, I am using the viewable quality of a typically taped off-air TV program.

I.e.: When I have made the master (on the Sony) and copied this to the SVHS Recorder, (in the VHS mode) the copy is cr*p to say the least.
It appears soft, or muddy, i.e. the chroma is noisy etc.

I have the Sony output connected direct into the SVHS via a composite (RF) cable,
(this is the only type of connection on a Umatic)
into the SVHS scart Composite Video Input.

I have also tried making the master recording direct to the Sony (i.e., without the mixer) and this seems to make little if any difference.

The quality of the Sony master recording appears slightly sharp (if that makes sense) but the general lum and chroma noise seems low, and the picture appear clear.

So..... Is this problem due to the poor spec of VHS, or am I missing something.

I don't have a handbook for the Sony, so I'm not sure what the settings should be, but I assume I just adjust the RF for highest signal without going into the red ?

Also, using the SVHS decks to make the master and dubbed copy, (i.e. without using the Sony) is worse still, and if this is the normal standard for VHS, then I don't know how anyone could even consider using SVHS/VHS for any serious work.

Regards Malcolm.

Hi Malcom,

If I remember correctly there is a socket on the BVU called DUB. This has amongst other things a Y/C output.

I will see if I can find the pinout for you.

By composite you mean Baseband not RF I hope. RF is different to Composite.

If you were using an RF connection between the machines, yes the quality would be cr*p!

The video meter on a BVU operates in two modes, when in EE or Record it shows the video level while in Playback it shows the RF off tape. If I remember correctly. This is the same as Sony Beta machines.

Using the Umatic as a master directly from the camera should give very good pictures in playback.

rgds

GG

[This message has been edited by GG (edited 04 June 2002).]

Hi

Found this,
http://umatic.palsite.com/home.html

The BVU800 is infact older than the one I had in mind. However they are similar.

As this is quite an old machine, it may be that the Video heads are worn. Do you know its history?

Also it is a High band machine and not SP as I first thought, the BVU850 was the first SP machine in this series. It definatly was better.

Also the DUB connector output is unfortunatly non standard, so I don't think this will help after all.

rgds

GG

[This message has been edited by GG (edited 04 June 2002).]

Hi, GG
Yes, there is a round 7 pin (female) socket labelled - Dub Out -
(Also a round 7 pin (male) socket labelled - Dub In - )

I'm not sure what the name (type) of plug, would plug into these, but its a similar size to a DIN, but the same strength (alloy) as a XLR mic connection.

If you can find the pin connections then that would help.

However, you say it's non standard, so does that mean that its not electrically compatible with VHS, or just that you don't know its wiring arrangement ?

Composite, yes I did mean Baseband, and not RF.

The Video Meter (on record) has a level control, and you can set this level (by a switch) to Auto or Manual.
I've tried it in both Auto and Manual, and it makes no difference.
(auto sets it to mark 3, i.e.: on the boarder of black and green on the meter)

There are 3 Sony Video-Out connectors, marked:
RF (off tape)
Video-Out (1) (I'm using this one)
I'm using a RG59U cable. - I've tried it with the usual phono type quality cables, which makes no difference.
Video-Out (2)

There are 2 Sony Video-In connectors, marked:
Video-In (1) (I'm using this one)
Video-In (2)

And, these can be switched to 75 ohm, on-or-off.
I've tried this in both on-and-off, and this makes no difference.

Hi, Malcom,

On the 1st point yes I can't find the pinout anywhere. Also It is Y/C but the C signal is not modulated by 4.43Mhz (PAL Colour subcarrier) so no good.

Video/RF meter "3" sounds correct, there is a small blue marker on the meter. This is where you should set the video level, this is only a guesstimate measurement, but probably good enough for what you want.

RF playback can vary, but around 3-4 is good, you can't adjust this, it is just a measure of the RF comming off tape.

The Video input termination should be switched on, 75ohms. Otherwise you would be recording at least double amplitude video levels which will look terrible.

I must say that recording stright to SVHS is looking like a better option.

Is there a good reason why you must Master to Umatic.

GG

[This message has been edited by GG (edited 04 June 2002).]

With regard to the AV5, I had one when they first came out & I recall that although it was fitted with Y/C sockets, it did not pass the quality of the supplied signal through. Got a feeling that it was made to the NTSC spec which has a lower quality than pal.

Re the "1/2 generation" if you use insert as opposed to assemble, I have to admit that in 14 years involved in video I have NEVER heard of this one!

Perhaps Sepulchre would care to expand the theory on this? maybe we could all learn something here!

Barry Hunter
Videos for all Occasions

quote:Originally posted by Barry Hunter:

Re the "1/2 generation" if you use insert as opposed to assemble, I have to admit that in 14 years involved in video I have NEVER heard of this one!

Perhaps Sepulchre would care to expand the theory on this? maybe we could all learn something here!

Barry Hunter
Videos for all Occasions

expansion is easy.
sony production team taught us all that doing sony production courses, using sony m7 cameras and sony hi-band recording decks.

try this and see if it works for you.

1. copy a tape to another tape
2. copy that tape to another tape
3. copy that tape to another tape
4. copy that tape to another tape.

you now have a 4th generation tape.

1a copy a tape to another tape using insert edit.
2a copy that tape to another tape using insert edit.
3a copy that tape to another tape using insert edit.
4a copy that tape to another tape using insert edit.

compare both tapes ..... which one looks better.

this of course does not apply to digital copying , but to analogue.

[This message has been edited by sepulcre (edited 04 June 2002).]

Hi sepulcre,

½ generation is perhaps misleading.

What you are doing when you copy in insert mode from one machine to another is the active video only, not the syncs as all of this is put onto the tape when you black it.

When you make a straight copy from one to another you copy everything, including any timing errors on the original, these timing errors get worse as you go down every generation, which doesn’t happen when you insert as each generation down has fresh timing pulses already from the previous blacking, just the active video its-self degrades.
This probably isn’t noticeable after only a couple of generations though.
In the Pro environment you would have VCR’s with a built in TBC or use a vision mixer with synchronised inputs this makes the timing issue unimportant. So you probably wouldn’t see a difference between 4th generation Insert or Assemble.

Yes you are correct degradation in the digital domain is completely different. Depending on whether the format is uncompressed or compressed.
Uncompressed for example Panasonic D5, you should be able to keep going down generations for ever without any degradation. But compressed formats are different. Some worse than others depending on the severity of the compression.

GG

quote:Originally posted by sepulcre:
this of course does not apply to digital copying , but to analogue.

[This message has been edited by sepulcre (edited 04 June 2002).]

I think all of us who were producing programmes long before the advent of digital know that (in theory) peak white occurs at the 8th generation however, this is in theory, in practice, in the real world, it entirely depends on the quality of the original rushes, the format in question and the quality of the machinery.

It was quite obvious from his original posting that Malcolm knows what he's doing and this is confirmed by the fact that he's using the BVU pre-roll to cue his next section.

Malcolm, if you are happy with the quality of the pictures coming off the BVU then, by process of elimination the problem must lie with the VHS machine on which you're making the dub copy. If you can lay your hands on an industrial SVHS/VHS machine like a Panasonic 7500 or 7600 Series you will see a dramatic difference; whilst they might all be called "SVHS" there is an amazing difference between domestic and industrial machines.

quote:Originally posted by Barry Hunter:
With regard to the AV5, I had one when they first came out & I recall that although it was fitted with Y/C sockets, it did not pass the quality of the supplied signal through. Got a feeling that it was made to the NTSC spec which has a lower quality than pal.
Barry Hunter
Videos for all Occasions

You are half-right here Barry.

All of these mixers, right up to the MX50 all work in the digital domain, they have to convert the signal from PAL otherwise they couldn't perform the tricks they do at the price. So the 'Bypass' button only routes the signal past the effects section and not the conversion.

Also, they contain a TBC, the affect of which is to delay the video by a number of frames. With the MX50 this was only one frame but I understand this was more on cheaper models.

In the early days rushes were being dubbed as A and B rolls through MX50 mixers, the programme was then being edited through the mixer then a client preview VHS was being produced back through the mixer and the end result was three frames out of sync! Whilst not strictly relevant to this problem I felt it appropriate to mention.

quote:Originally posted by mhP:

In the early days rushes were being dubbed as A and B rolls through MX50 mixers, the programme was then being edited through the mixer then a client preview VHS was being produced back through the mixer and the end result was three frames out of sync! Whilst not strictly relevant to this problem I felt it appropriate to mention.

that is why the mx50a was created in america.
that has an audio delay to match video and audio.

we bought a sony audio effects box to do the same thing , with our mx50

Thanks everyone so far, for your comments, very interesting.

GG,
The reasons for using the Sony as a master are...
Sony is of a superior tech standard, and 'should' therefore do a better job, then SVHS.
After-all that's why it was (and still is) used by some production and TV companies etc.

And, I've tried using only SVHS and the quality is worse !

Also, as I get the same level of VHS picture quality on the dubbed final copy, regardless as to whether I'm using the Camera tape (in SVHS) as a Master, or a SVHS Record Deck tape, as the Master (I have 2 Panasonic NV-FS200B SVHS Video Recorder.)....

Seems to suggest that it's the SVHS and VHS standard (just 250 and 400 lines[supposedly]) that's the main problem.
(+ other electronic shortcuts in the systems design)

That's why I original asked if anyone had gone through the same problem as me.

A first generation recording in SVHS and probably VHS is ok, if that was to be the only copy, i.e. the copy the viewer would be watching.
(ie:A off air TV program is ok, but try making a copy of it!)
But the second you make a copy, then its copy ceases to be good enough !
If someone knows different, then please tell me.

Hi Malcolm

quote:

A first generation recording in SVHS and probably VHS is ok, if that was to be the only copy, i.e. the copy the viewer would be watching.
(.[/B]

If the above is acceptable quality wise how do you get the poor copies ?

I've duplicated from all consumer analogue formats using a distribution amp with acceptable results.
Regards
Charles

Hi again Malcom,

This certainly is a puzzling one. Either there is a problem with your equipment somewhere or you are expecting more than your equipment is capable of.

I have to disagree that Umatic is used still by some production and TV companies. I think you will be hard pressed to find one. Umatic is an old format although it was good in its day. Still found in colleges and schools though.

If you really want a high quality master you need to start with DV or analogue equivalent like BetacamSP or better. I know this doesn’t help though!

As for the Pana mixer, you will probably find that in the specs it is a 6bit machine which by modern standards of DV (8bit) and digital broadcast formats of 10bit and 12 bit is not very good. Also if the sample rate frequency of the analogue to digital and digital to analogue converters gives a video resolution of less than 3.6Mhz (SVHS deduced from 400 line resolution) then this will all contribute to a reduced resolution also. Broadcast specs for a 4:3 aspect PAL is around 5.5Mhz.

I think its unlikely that the cheaper one has a longer delay though it as that will require more memory and would cost more. If you can do a freeze on the mixer and select field or frame. Then it will have enough memory for 2 fields, which is pretty much standard.

Does the Pana mixer have a built in audio delay?
If so I would expect that it has the correct delay time set, it would be rather stupid to go to the effort of including it then setting it wrong.

If it doesn’t have a delay this is why you get the audio sync problems.

Rgds

GG

[This message has been edited by GG (edited 06 June 2002).]

Hi everyone,
I'm going to make some final tests, and then I'll get back to you (hopefully later today)

GG:
I agree that Umatic has now been superseded by higher quality systems, including beta and digital systems, but it is still used in some less affluent parts of the world, and by quite a few small production and advertising companies.

However, I was hoping that I could at least, produce the current project on my current equipment, and then hopefully when funds allow, I would upgrade to a better system ASAP.

Also, not sure why you say...
"If it doesn’t have a delay this is why you get the audio sync problems."
As I don't have a audio sync problems !
At the moment, anyway ;) !

Regards Malcolm

GG,

The “400 lines resolution” of SVHS is equivalent to a video bandwidth of 5.1 MHz (Not 3.6 MHz).

Alan

Hi Malcom,

Sorry I thought you ment England!

You are probably correct, some contries may well still broadcast from U-matic.

Iraq TV for example I think broadcast from U-matic, VHS, well anything they can get their hands on I would expect

What I said about the audio delay was a responce to the several replies above.

Just one run through the mixer without an audio delay would only put your copy a frame out of sync with the audio, you probably wouldn't notice this. However if you ran the copy through, then it would be 2 frames out. See what I mean now.

The mixer may well have a built in audio delay, in which case if you fed the audio through the mixer also, then there should be no problem. You will have to check this.

But 1 frame isn't really going to be noticable.

rgds

GG

Hi Alan,

How did you get to 5.1Mhz?

I did use the correct formula

Some earlier broadcast formats had trouble breaking the 5Mhz bandwidth!

Infact for 625 PAL, discounting the lines for blanking only needs a bandwidth of 5.2Mhz for a 4:3 aspect, and about 5.5Mhz for the full 625.

rgds

GG

[This message has been edited by GG (edited 06 June 2002).]

GG,

I was not commenting on how well deserved the “400 lines” claim is for SVHS; only on the equivalence between the spatial resolution and video bandwidth. Without defined limits, resolution or bandwidths are meaningless but in translating from one to the other the limits should remain the same.

“400 lines resolution” means 400 lines per picture height.

Which is (400 x 4/3) = 533.3 lines per picture width.

Which actually means 266.7 cycles per picture width, since one cycle represents two lines.

It takes 52 microseconds to scan across a picture width.

So we can fit 52 cycles of a 1 MHz sinusoid into a picture width.

So 266.7 cycles will require a bandwidth of :

266.7 cycles / (52 cycles / MHz)

= 5.13 MHz

So “400 lines per picture height” is equivalent to a video frequency of 5.13 MHz.

Alan

Hi Alan,

This might be true but in the real world it is incorrect. This would apply to any video recording/transmission system whether its VHS or beta!

The thing you forgot is known as the Kell factor.

Basically practical systems cannot cope with picture detail approaching the vertical spacing of the line structure – i.e. the detail falls between the lines.

So the Kell factor was come up with that shows the theoretical limit that can be transmitted, it has a value of 0.7.

If you now include this into your equation you will get a more sensible answer.

Eg N=LxAxK

L=number of active lines
A=Aspect ratio 4/3
K=0.7

This will give you N, the number of “brightness changes”

Then 52uS/N = Tns

Therefore the bandwidth required for the video signal is
F=Frequency

F=1/2T

Believe me this is right

Rgds

GG

[This message has been edited by GG (edited 06 June 2002).]

Found this.

Quick scan looks like it might explain it better than I did, although it is for 525, same principle though.
http://www.bh.rmit.edu.au/mrs/kpm/EPCR/CR_VidBandwidth.html#Vertical

rgds

GG

Kell factor is for vertical resolution not horizontal as the average TV is more than capable of showing far more than 400lines. Indeed, as the 400 lines is measured visual, the Kell factor has already been applied.

Secondly, as I've managed to (just about) record the PAL subcarrier on SVHS luminance, this suggests that SVHS has some resolving at 4.43MHz, if it was a 3.6MHz rolloff this wouldn't be possibly.

See you earlier,

Steven

Hi,

Yes I know!

Horz resolution is much easier to calculate.
Basically
t=number of changes
t line= line length
N= number of brightness changes

t=t line/N

then
fvideo=1/2t.

GG

[This message has been edited by GG (edited 06 June 2002).]

IIRC the WJAVE7 had y/c inputs but the AVE5 only had composite

Steven,

Found this link on video bandwidth.
http://www.bealecorner.com/trv900/sweep/sweep.html

If you look at the response of the SVHS deck they tested, you are right it does amazingly just about resolve up to 5Mhz but it is extremely attenuated. Infact the amplitude is less than half after 3Mhz.
The “brightness changes” at this point would be varying levels of grey. Not much use!

GG

[This message has been edited by GG (edited 06 June 2002).]

GG,

As Steven says, the Kell factor applies to the VERTICAL resolution which is determined by the number of (horizontal) scanning lines. There are 575 (or 576) scan lines in our present UK TV system and the vertical resolution lies somewhere between 288 lines and 403 lines but is essentially the same for all VHS, SVHS, Hi-8, DV, Betacam, digibeta...... the lot.
Note that lines of resolution are not at all the same thing as scanning lines. To avoid this confusion it is much better to describe resolution it terms of “cycles” , which hopefully should be unambiguous. There is one cycle for every two lines of resolution. The vertical resolution therefore lies between 144 cycles per picture height and 201 cycles per picture height and is not directly affected by the video bandwidth.

None of the above has anything to do with the question of the “400 lines” resolution of SVHS. This refers to the HORIZONTAL resolution, which IS linked to video bandwidth. Unfortunately the word “lines” is used. Again it is much clearer to use “cycles per picture width / height”.

The number of cycles that can be resolved is measured across the width of the picture (the horizontal resolution). However it is nearly always written in terms of the number of cycles across a width of the picture equal to the picture height (or cycles per picture height for short). This is still a horizontal resolution but is a fairer way of comparing differing aspect ratios.

On a practical note, the recorded output from my SVHS and Hi8 recorders shows 5.25 MHz bars from test card F, albeit some 10 dB or more down on the low frequency response.

Since 5.25 MHz corresponds to 409 lines per picture height, I think the claim of “400 TV lines” for SVHS and Hi-8 is justified, certainly for the consumer market.

Alan

Hi all,

It is amazing how a few words can generate such a heated discussion, not that that is a bad thing!

Isn't that why we are here?

I think at some points we have been talking at cross-purposes.

However I will say that the two formulae for calculating Horizontal and Vertical resolution are correct.

I have run frequency response tests on numerous VTR’s from VHS through to Digibeta over the years. For most if not all machines, it is part of the line-up procedure. S-VHS doesn’t reach past 5Mhz, infact as I said is highly attenuated over 4Mhz. So am surprised that you could make out anything at 5.25Mhz!

The original intention of this thread however was to help Malcom with his quality problems.

Have you any suggestions?

Rgds

GG

[This message has been edited by GG (edited 06 June 2002).]

GG,

If the SVHS luma response does not, as you say, “reach past 5 MHz”, then the manufacturers’ claims of 400 TV lines resolution are untrue.
(since 5 MHz video frequency corresponds to 390 TV lines).

It should be noted that the full 400 TV line response will only be realised when using the S-video inputs or a composite input which feeds an internal “comb filter” to separate luma and chroma.

Alan

Alan,

Now to start from scratch,

SVHS is supposed to have a horiz resolution of 400 lines

From the formula I quoted,

400 changes in 52us (active video)

So that is 52/400= 0.13

now to convert into f

1 / 2 x 0.13=3.846mhz

Therefore SVHS resolution of 3.846mhz and not 5.13mhz

BTW 5mhz actually equates to 520 lines

I admit I must have worked it out incorrectly before to get 3.6mhz but it is alot closer than 5.13mhz and hopefully got across the point I was trying to make that if the mixer had a lesser resolution than SVHS then it would also degrade the signal.

BTW these figures have no relation to aspect ratio as line length doesn't change for PAL it is 64us, 52us of which is active video.

Yes I am only talking about Luma, if you took into account the much lower resolution of the Chroma signal also you would need to be talking about total video bandwidth including vertical resolution this is yet another formula of which I dont have to hand.

rgds

GG

GG,

As I have been at great pains to point out, the “400 lines” refers to a horizontal resolution of 400 lines across a width of the picture equal to the height, for an aspect ratio of 4:3. This is a standard way of describing horizontal resolution for television (and it was also used for film, I understand).

The same resolution could equally well be described as 300 lines per picture height for an aspect ratio of 16:9.

Both mean a horizontal resolution of 533.3 lines per picture width.

We must know the aspect ratio when horizontal resolution is expressed “per picture height” as is needed as the link between height and width.

Using a horizontal resolution of 533.3 lines per picture width gives an equivalent video frequency of 5.13 MHz.

Alan

Alan

I can see this this is getting us nowhere, and I'm now no longer interested in following this argument.

Bye

GG

Malcolm how are you getting on with your problem?

Hi GG...
I'm still making a variety of tests, and I'll get back to you as soon as possible.

I will need to test the performance of the camera, do you know, so...

do you know if anyone makes a 'Test Card' ?

Hi Malcom,

I'm sorry to say proper resolution charts/boards are very expensive.

However If you have a good printer that will print A4/A3 you should be able to make your own. Obviously it isn’t going to be as good as the real thing but it should give you an Idea.

Also to bear in mind you must print it the correct size otherwise you are wasting your time.

I have found this site (isn’t Google great) where you can download a resolution chart which ought to be ok for your needs.
http://www.bealecorner.com/trv900/respat/

Rgds

GG

Interestingly there is a good explanation should you care any more , about resolution in its different forms (video resolution, horizontal resolution and vertical resolution) of which when manufactures state resolution it is normally horizontal resolution.

GG

[This message has been edited by GG (edited 07 June 2002).]

Malcolm & GG,

The EIA resolution chart 1956 is well worth printing out from the Beale site.

When you do print it out, observe the various resolution numbers printed on it. (200, 300 400 etc.)
.
Since we have been discussing “400 lines”, measure the width of a line labelled “400”. It will be more accurate to measure the width of a block of “400” lines and divide by the number of lines in the block.

Now measure the width of the chart picture (from the arrow head on one side to the arrow head on the other side.

Divide the picture width by the width of one “400” line and stand back in amazement!

For the result is not 400 as GG would have us believe!

If you have carried out the measurements accurately the result should be 533.3 but accurate measurement may require much care and a magnifying glass!

On my printer at A4, the 800 lines / picture height part of the resolution wedge is easily resolved on the paper so you might be able to use an A4 printed chart for camera testing. What I have not been able to do is get an accurate grey scale and good chart resolution from the same print. (See Beale’s write up). However the good grey scale print has adequate resolution up to about 550 lines / picture height, which may be adequate for your purposes. If you can, use an A3 print.

Alan

Here we go again. Without trying to get flamed

I have carefully read back though the thread and see as I pointed out that we have indeed been talking at cross purposes.
I have been talking about horizontal resolution and can assure you that the simple formula I gave for this is correct. However Alan has been talking about video resolution, and yes I see now your formula for this is correct Alan. But was talking about horizontal resolution, this is measured as the number of changes over a line length 52us(active video) that the video equiptment is able to achive.

You can do the test for yourself with a waveform monitor and multiburst or sweep on a test tape played back on a SVHS and tell me then that its not able to usefully resolve 5.1mhz horizontally.

Bandwidth, video resolution, vert resolution and horiz resolution, not to mention the lines method of measuring resolution can be confusing to anyone and are sometimes somewhat ambiguous. However I’m sure that we may all have learnt something from this thread.

Practically speaking It is important to know the formulae and apply them but in the real world there are so many other contributing factors not to mention the deficiencies in PAL itself.
For example as your VCR ages and wears the practical limits of what a machine is capable of reduces, especially resolution, here I am talking about head wear and drift in analogue electronic circuits.
Which is where we originally started. In theory Malcoms setup should produce great results, but it isn’t, so we need to find out what is the “bottleneck” should we say, that is causing the resulting copy to have poor resolution.

There really is nothing to be gained any more from arguing about this any further.
If people want to know any more about it there are plenty of very good books written by real tefal heads like W N Sprosonon or John watkinson for example on everything you need to know about PAL/NTSC Video.

Rgds

GG

Also another usefull link: http://www.jamesbrice.com/html/broadcast_web_links.html

[This message has been edited by GG (edited 08 June 2002).]

I am still firmly of the opinion that the problem lays in the inadequacies of the domestic equipment which could be solved by the use of an industrial SVHS/VHS to make the dub copies.

Malcolm, you can get a set of test charts from www.compositevideo.co.uk at £189.00 + VAT

[This message has been edited by mhP (edited 07 June 2002).]

I think it is worth summarising the relationship between lines of horizontal resolution per picture height and the corresponding video frequency.

250 lines/picture height (VHS, Video 8) 3.2 MHz

400 lines/picture height (SVHS, Hi-8) 5.1 MHz

500 lines/picture height (DV, DVD) 6.4 MHz

NB: All the above are for an aspect ratio of 4:3

If you want a “formula”: divide the number of lines per picture height by 78 to give the corresponding video frequency in megahertz.

Alan

Alan,

This is the last I am going to say on the matter.
This just proves what I have been saying all along, you have just proved me right. Thank you.

400/ 4/3 =300

300/78 = 3.846mhz

By the way manufactures nearly always quote horizontal resolution for tape formats this is the 400 for SVHS which as I said equates to 3.846mhz. You can check it yourself with a scope as I said earlier or take a look in a service manual.

rgds

GG

GG,

Why did you divide the 400 lines/ picture height by 4/3 ???

I wrote:

“divide the number of lines per picture height by 78 to give the corresponding video frequency in megahertz”.

The number of lines per picture height (claimed by the manufacturers in the case of SVHS) is 400.

Dividing 400 by 78 gives 5.1

So the video frequency corresponding to 400 lines per picture height is 5.1 MHz.

It appears that you are still claiming that they mean 400 lines across the picture width. They do not. They mean 533.3 lines across the picture width, just like the EIA resolution chart 1956 and just about everyone in the television engineering world.

Alan

Look,

Its not 400 lpph its 400 horiz, check it, you will find I am right.

Actually, just forget it, its clear this isnt going anywhere.

Bye.

GG

[This message has been edited by GG (edited 08 June 2002).]

Now now, you guys, take a powder and calm down...

THE WHOLE POINT IS THIS !!!

Sorry am I shouting ?

What ever the Standard in question is, VHS, SVHS, 8mm, Hi 8, Digital 8, Mini Digital, etc., etc...

All manufacturers of all these standards...

CON US MUGS (the buying public)...

into thinking, that because something is of a particular 'standard', then that's the 'standard' we ultimately buy.

It ant so...

Because something is say, of the SVHS standard (or whatever) does not mean that the SVHS kit we buy, lives up to the FULL true spec, of the SVHS standard (etc).

The shop sells us an xyz model and brand of SVHS camera, only for us MUGS to later find that its performance is not as good as some other, model and brand of SVHS camera !

If it's to a standard then it should perform to that standard !

Otherwise it is being sold under false pretences !

But, for some reason we accept that this is how it has to be !

If you disagree...
Please don't try to justify this con by saying it is down to price, because it ant,
Initially, price has no bearing on the quality !

The main thing that governs the selling price (manufacturers price) is what they think us mugs will pay for it !

Then each mf makes 999 different models with supposedly different features and benefits, all to this mythical (SVHS) standard, at 999 different prices, and waits to see what us idiots make of it !

Confusion and misinformation is the name of the game, and is the main weapon in the mf arsenal.

If you want proof of this, just try to compare the SAME HiFi unit, in different retail outlets, most of the big chain stores have their own model numbers on sale, which are not available (as that model) in other competing stores, even though the spec and appearance is the same or similar elsewhere.

All this is designed to make it dam hard to compare model to model, and price to price.

Result, we buy on a hunch, or more likely, desire, i.e., I like the look of that, rather then this spec is a really good spec.

So, VHS, SVHS, 8mm, Hi 8, Digital 8, Mini Digital, etc., etc....

Are all just used as shorthand, so we can ask the shop, for whatever 'standard' some publication or other tells us is best !

The whole point is this...

The only time this argument is perhaps less relevant, is when you are checking out broadcast standard equipment.

Do you think the BBC buy their equipment, based upon some sales guy (who can barely speak his name) telling them, yer mate, that a better model than that.

No, they have the equipment on Apro, and ONLY buy it, if it lives up to their needs and the manufactures claims.

Och !!! £"$%^&*()_+

I've just fallen off my soap box !!

That's why my original question asked if anyone had, had the same experience as me,

A spec means nothing if, no one applies it rigidly !

So, it's ultimately how it performs in the real world, rather then the ideal spec, that no one sticks to !

Phew !!

Now, I'll have a lye down in a dark room.

Malcolm.

Cheers Malcom,

I feel better now , can I come out and play again?

You are very much correct!

Manufactures use all sorts of ways of making their figures look better. As you say, how many people buy a domestic VCR and then connect it up to test equipment to check it is as the manufactures say, or even does it measure up to the supposed specs laid down for that format, not many I should think, then what do you do, take it back to the shop and say it doesn’t measure up according to your test equipment. I think you might get laughed at! At the least you may get some odd looks!

As with broadcast gear, it mostly costs a darn sight more as you said.

When you are spending for example

Sony Digibeta about £25,000
Panasonic D5 originally were about £55,000
Sony 1” VCRs were originally about £100,000
And the original Ampex 2” were something around £200,000
Scary stuff!

You defiantly want to make sure it does what you want to the specs set out for that format.

Rgds

GG

So, Malcolm, if the technophiles have finished arguing about meaningless figures and specifications, have you come to any conclusion yet?

Just to clear up some earlier points the AVE 5 did indeed have svhs in/out but it was wired internally in COMPOSITE not SVHS (in fact there was a guy who used to modify it up to 400 lines and give you colour correction for about £250). So the machine is not outputting 400 lines or anywhere near it. This does not matter though because the original poster was only taking a composite feed out of the mixer anyway but I just thought I would clear up the SVHS or not debate on the wee mixer. Great wee mixer it was too!

svideo splits the y and c signals , composite keeps them together , but where does it state that less lines are carried over composite than over svideo ?

my mx50 carries same no of lines across both composite and svideo connections.

Thanks Jimmy! My earlier post was similar to your own with out having the facts that you stated!

Barry Hunter
Videos for all Occasions

S-Video is the connection and stands for seperated Y/C (not for S-VHS)

Composite = Y and C Combined.

S-VHS is Super-VHS, the inicreased VHS standard from 250 to 400 resolution, suppposidly !

malcolm

Sepulcre is quite right. Composite and S-video have potentially virtually the same luma resolution.

However with the composite signal, a comb filter is required to separate the luma from the chroma and still retain the luma resolution throughout the modulated subcarrier region (from about 3.5 MHz to above 5 MHz).

If an ordinary low-pass filter is used it must reject this modulated subcarrier region and so the luma response would be limited to about 3.5 MHz.

However, since we have been assured beyond doubt that SVHS is limited to 3.8 MHz, there would seem little or no point in S-video inputs / outputs or comb filters for the composite input on an SVHS recorder.

Alan

Hi Sepulcre/all,

The problem with composite comes when you try to separate the video components out into Y/C…etc….. you will need a Comb filter to do the job properly and some are better than others.

If you are interested.

Here is a link which explains the difference between Y/C and Composite. and why its a good Idea to keep the Luma and Chroma separate. Its for NTSC but the principal is the same, figures are different though. Couldn’t find a good one for PAL.
http://www.cybertheater.com/Tech_Archive/YC_Comp_Format/yc_comp_format.html

happy reading

GG

[This message has been edited by GG (edited 08 June 2002).]

Alan,
You need to look at the difference between horizontal resolution and video bandwidth.

GG

i know the diference between svideo and composite , i was querying why the statement of less lines being carried was made.

if the statement is true then there is a poor quality signal being fed thru the mixer which won't help the quality of the final tape.
that may therefore be the problem and not the camera/umatic composite connection which will be transfering all the info properly.

Hi, everyone...
I've tried to print out the test card mentioned by GG.

Does anyone know why my printer won't print the image to the correct width, i.e.:
(my printers a - Epson Stylus colour 760)

I've downloaded the image file, and resized it to - 11.5inc x 8.5inc - as stated on their web.

In my printers page set-up...
I've made a - custom page design - that's 12inc x 9inc. and (ie 1/2 biger then the image)
Then I selected this as my - Paper Size -
Then I set the - top and left margins - to their minimum (2.96mm = approx 1/8th inch)

Then I put some suitable paper into printer, and printed it.

Result:
The image prints ok, but nothing prints past about 8 inches, eventhough the paper is big enough for the full image.
I've also repeated the above, with wider custom page settings e.g.: 12.5 x 9.5 inc etc.

Nothing will print past the 8" mark.

I've also tried one of the - standard setting - legal size - 8.5" x 14"

This prints nearly to the end of the margins i.e., 8.25" (which is correct allowing for the 1/8" x 2 margins)

So it seems that the printer is not recognising the 8.5" setting in my custom page design !

Any ideas ?

Malcolm. !"$%^&*()_+

what operating system is your computer using ?

on xp you right click the file , choose preview , then choose print and follow the instructions in the wizard.

Hi, again...
Re your observation about the mixer...

Test so far show that the problem occurs without the mixer connected.

e.g.: SVHS to SVHS using the S-Video cable.

I'll comment fully when I've had chance to test the camera with the test card.

(did I hear someone mutter, something about when hell freezes over ?)

Malcolm

Hi Malcom,

I too would like to find out why this occurs when printing out large pictures/photos.

I have a vary old Epson Photo, when I print full size high definition pictures it never completes. The way I used to get around this was to reduce the resolution therefore file size, not a satisfactory solution really and certainly no good in this instance as you want the best resolution possible.
I used to use NT4 now Win2K, same problem, have tried changing all the settings I could find to no avail. I wonder if it is anything to do with the size of the spool file created???

Anyone!

GG

GG
In this case,
I don't think it is the size of the file...

I got fed up of wasting ink, so I made a test file in PSPro,

i.e. I made a new blank image with a cross on it, to the correct size,
and I still get the problem on this.
Malcolm

GG.
I know why the printer won't print any wider !

It's becuase the setting for the - standard setting - legal size - 8.5" x 14"

Is the printers max print width, derrrr.

EUREKA !!

Hi, everyone... GG,
I have now made a crude test using the test card you mentioned...

In all tests the TV is connected to the Dub machine via its RF connector.

Basically, I have made two types of tests...

1) Master tape recorded in SVHS on Camera Tape, and...
Then dubbed direct to the Record Deck at VHS.
During Dubbing, both S-Video and Composite cables were tried from the Camera to the Record Deck,
and the performance (from a number of lines point of view) was about the same.

The viewed lines on the TV during the Master Recording was about 275 lines, (not 400 !)
then gets progressively muddy from 275 up to about 300 lines, and non existent above 300 lines.

And, the viewable number of lines on playback =
From the Master Copy = about 275 lines.
From the Dubbed Copy = about 210 lines.

2) Master tape recorded on SONY, (so camera tape not used) and...
Then dubbed direct to the Record Deck at VHS.
During Dubbing, Composite cable was used from the Sony output to the Record Deck.

During Master Recording, both S-Video and Composite cables were tried from the Camera to the Record Deck,
But, the mixer had to be connected while using the S-Video cable, because I didn't have the correct type of connector readily available.

The viewed lines on the TV during the Master Recording was about:
240 to 250 lines, using the Composite cables, and no mixer.
230 to 240 lines, using the S-Video cables, + the mixer.

The Dubbed Copy = about 210 to 215 lines, in both cases.

And I think I have also tried just about every-other permutation of recording and copying, and get more or less the same results.

Conclusion:
The quality of the final dubbed copy (from a resolution point of view) is about the same in both cases, i.e. using Sony Master or SVHS Master.

But, the Sony gives a better viewable copy because there's less Chroma noise, which makes the underlining picture clearer.

But both seem flat, (compared to the original masters) due to the reduced resolution.

Seems like I need to try a better camera ??
What does everyone think ?

The final dubbed copy is about 40 lines below the VHS standard, (250-210)
40 is about 20% of 210 so, if the problem is ONLY with the cameras output, then

Would an increase in the camera output by 20% (275+55) to 330 lines (or more) solve the problem ?
And why is it 275 lines anyway ? When the SVHS standard is 400 lines !

NB: I have also made similar tests, by recordings an off-air TV broadcast in SVHS.
(of live, and studio recorded programs) and then used this as the master...

And, the dubbed quality was acceptable, with little difference from the master.

Obviously, the broadcast signal will be of the highest resolution !

Any (practical) thoughts Folks ?

All donations gratefully appreciated.

One things for sure - NO ONE should buy a camera without first trying it on a Test Card !

Malcolm

Gents, I've only just read this thread.

All the test charts talk of resoltion by referring to picture height, not width. So SMPTE, EIA, RETMA etc charts all talk of umbers of lines (or possibly cycles) per picture height, even when dealing with horizontal resolution. That explains the factor of 1.333...., being 4/3, aspect ratio of the picture.

Hi Alan,
So what does this mean exactly ?
Malcolm

Malcolm,

(wrong Alan I know!)

I think it probably means that your camera is, how can we put this, not very good!!

I have just run a quick test using the very same EIA resolution chart 1956 and a Sony V6000 (analogue, single imaging chip, 10 years old).

The horizontal resolution from the camera directly is about 430 lines per picture height (ie. as read directly from the numbers on the chart).

From Hi-8 tape playback from the V6000 recorder/playback section, the horizontal resolution is about 400 lines per picture height. The 400 line part of the wedge is clearly visible at 6 picture heights viewing distance.
The picture is of course noisier off tape than live from the camera.

(In both cases (live and off tape), the vertical resolution is about 300 lines per picture height (but that is inherent in the 625 line interlaced system).

SVHS should be as good as Hi-8 for resolution (and in my experience a little less noisy).

Is your video monitor above suspicion?

Alan

[This message has been edited by Alan McKeown (edited 10 June 2002).]

Malcolm,

I have just noticed this statement on rereading your post.

“In all tests the TV is connected to the Dub machine via its RF connector”.

Does that mean what I think it means that you are using an ordinary TV set (with never a comb filter in sight!) via its aerial input socket (ie you are using an “RF” (modulated) input signal to the TV?

The best you could hope for would be about 3.8 MHz video bandwidth which corresponds to a horizontal resolution of 300 lines per picture height.

Hope I have misunderstood the "video monitor" status!

Alan

Thank you Alan, you say...

""The horizontal resolution from the camera directly is about 430 lines per picture height
(i.e.. as read directly from the numbers on the chart).""

So, if I understand you correctly, this means that...

The resolution along the Horizontal bars -
To the left and right of the - centre vertical block of (200f) lines -
Is 430 lines.

and...
""(In both cases (live and off tape), the vertical resolution is about 300 lines per picture height (but that is inherent in the 625 line interlaced system). ""

So, this means that...
The resolution along the Vertical bars -
Above and below the - centre vertical block of (200f) lines -
Is 300 lines.

Ok, but what do you mean by...
"" per picture height (but that is inherent in the 625 line interlaced system). ""

If my above interpretation of your comments are correct, then my test previously outline more or less agree with your test...
On the master Recording !!

So did you then make a dubbed copy of your master ? Down to VHS ?
(i.e. second generation)

And if so, did you then get the same Horizontal and Vertical Resolution (430/300 lines)

""Is your video monitor above suspicion? ""

Yes, because the - off air programs (and subsequent dubbed tests) are ok
And the dubbed tapes have been played back on two different TVs, which both give good off-air pictures, and good playback of the Master Recordings.

-----
[in answer to your second post i.e.:
“In all tests the TV is connected to the Dub machine via its RF connector”.

Yes, surely that's how most people will have their TV connected to their Video, when they are viewing normal TV programs, and when playing Video Tapes in general, hire tapes etc]
------

Malcolm

Malcolm,

To take your questions in order:

“So, if I understand you correctly, this means that...

The resolution along the Horizontal bars -
To the left and right of the - centre vertical block of (200f) lines -
Is 430 lines”

No, this is not the case. Horizontal resolution is the resolution in the “horizontal” direction (“horizontal” because the screen surface is imagined to be in a vertical plane with the wider dimension horizontal). So we measure horizontal resolution across the width of the screen. This is done by using VERTICAL lines (or nearly vertical in the case of this particular chart). The more vertical lines we can resolve across the WIDTH of the screen the higher the HORIZONTAL resolution.

So you could use the width of the screen as the unit of distance measurement for horizontal resolution and there is nothing wrong with that so long as everyone knows what you are doing; ie. provided you state “lines per picture width”. However it makes more sense, if you think about it, to use the same unit of distance measurement for both horizontal and vertical dimensions. For one thing this allows immediate comparison between horizontal and vertical resolution. The unit of distance measurement chosen is the picture height, which makes for easy resolution comparisons between different aspect ratios.

So we use the same unit of length for both vertical and horizontal spatial frequencies, which are in effect what we are measuring. Spatial frequency is measured in cycles per unit length (analogous to the more familiar “temporal” frequency measured in cycles per unit time (usually cycles per second or Hertz.)

[The transformation between the spatial frequency domain and the temporal frequency domain could be viewed as the essence of our television system and is accomplished by the process known as “scanning”].

So to measure HORIZONTAL resolution we use the (near) VERTICAL lines above and below the centre 200 lines per picture height (lpph) “square”.

(2) I only included the VERTICAL resolution measurement out of interest for there is nothing (for our present purpose) to be done to change it. It is measured using the (near) HORIZONTAL lines to the left and right of the central section. The exact figure would depend on the picture content etc.

(3)

""Is your video monitor above suspicion? ""

Yes, because the - off air programs (and subsequent dubbed tests) are ok
And the dubbed tapes have been played back on two different TVs, which both give good off-air pictures, and good playback of the Master Recordings.”

If you are happy that’s fine but there is no way you will achieve anything like the potential 400 lines per picture height of SVHS etc., using a composite input (without a comb filter) and even less chance using the aerial input. As we have said, about 3.8 MHz is about all you can reasonably expect because of the need to get rid of interference from the colour subcarrier region.
You might just squeeze 4 MHz if some colour interference is tolerated. 4 MHz video frequency corresponds to 312 lines per picture height of horizontal resolution.

(4) I have not tried a second generation recording. Will try when I get time and let you know. Could try SVHS for first generation and VHS for second as well as two SVHS.

Hope the above was of some help and hasn’t thoroughly confused!

Alan

OK Alan (M),
Thank you very much for your detailed reply.
It was very, very helpful.

Lets cut to the chase !

I have just made a recording in my camcorder.
I started in the S-VHS Mode, and then switched to VHS mode.

The TV (RF connected) during recording shows about 275 lines, and a cut off at about 300 lines.

This seems to agree with your 3.6 to 4mhz cut-off point, you have quoted.

On playback the resolution =
SVHS (still) 275 lines.
VHS (still) 210 lines. (or there abouts)

So, the best resolution on VHS is 210 lines, although the standard is supposed to be 240/250.
(my camera book says "better then 250 lines")

So, due to the RF connected TV, we can only 'see' up to say 300 lines on the TV, so the 250 lines of the VHS standard, should be visible.

When I make a dubbed copy of the SVHS master, down to VHS, I get 210 lines.
Which is the same as the above (master tape) camera test !
This suggests that there is no fault in any of my equipment, but the problem (of 210 VHS lines) is just the VHS standard.

*Because I only get a max of 210 lines regardless of what equipment is used, and regardless of whether they are firsts or second generation VHS recordings, makes little difference from a resolution pov.

The lack of VHS quality therefore, seems to be more to do with the increased Chroma noise, then the low resolution, i.e., the increased chroma noise, on the dubbed copy, makes the already low resolution, appear much worse.

Question: If the best resolution in VHS is 210 lines, why does my off-air taped TV programs look ok ?
Is this just because the chroma noise on these transmissions is usually very, very low ?

If my above deductions are correct, then how do I get an acceptable dubbed VHS copy !

** Alan, I would be interested to know what VHS resolution you are getting from your test card.

Many thanks... Malcolm.

One thing to consider is the fact that just because you can see 275 lines on the SVHS version it doesn't mean that the signal is any good at that level.

What I suspect is happening is that you are getting a pretty poor signal from 200-odd lines up but the human eye being what it is still makes out the detail. However when this is recorded as VHS the poor response at the high end turns something just recognisable into mush. If the signal were perfect up to 275 lines I suspect that you would indeed see 250 lines of detail from the VHS tape, it wouldn't be a very good signal at that frequency but the wonders of the human eye would still work.

I would guess that the horizontal frequency response of your camera is something like this:

You would be able to see detail quite far up, just don't expect to be able to record it on a VHS deck!

Maybe the answer to why you get better results with off-air signals is that they were shot with much more expensive cameras that had a better response at higher frequencies

Note: Credit for the picture goes to John Beale at http://www.bealecorner.com 'cos I stole it from there!

[This message has been edited by Matt Beard (edited 11 June 2002).]

Matt, thanks...

You say...
"One thing to consider is the fact that just because you can see 275 lines on the SVHS version it doesn't mean that the signal is any good at that level.
What I suspect is happening is that you are getting a pretty poor signal from 200-odd lines up but the human eye being what it is still makes out the detail. "

But if that were the case,
why is the original master recording acceptable, (not brilliant, but acceptable)in both SVHS and VHS.

And on a copy (of that master) the chroma noise is what really spoils the picture.

So...
What are you saying...
A better camera, will resolve 250 lines on VHS ?

NB: following Alans point...
my camera may be resolving say 400 lines, but I just cant see above 300 lines, because the TV is connected via its RF socket.

Q: How do you connect a TV or Monitor, so you can see 400 lines (SVHS) anyway ?

With a S-Video connection on your TV or Monitor, I presume, do they make them ?

Malcolm

Hi Malcom,

I am not going to say too much but this guy explains resolution very well in a reasonably non techy way which should fill in any gaps. Don't pay too much attention to the figures as it is again for NTSC/525 but the principal is the same.
http://www.elitevideo.com/new2.htm

I'm not so sure about TV's some of the better ones may well have a 2 line comb filter or similar, However I've taken a look at a couple of service manuals for domestic TV's only low pass and band pass filters, but proper monitors(i.e.Sony BVM & PVM range or JVC TM range) DO have comb filters. All advertise to give 500+ horizontal resolution, using the correct input.

As with your TV. Does it have a scart or AV socket/s

One variation on the scart theme does support Y/C.

If the TV supports it it would show something like AV-S or AV S-Video.

Hope this helps,

GG

[This message has been edited by GG (edited 11 June 2002).]

Hi Malcolm,

I have been busy today so not had time to do any measurements but will try to measure the VHS resolution tomorrow.

As you say, the manufacturers’ claim for VHS horizontal resolution is 250 lines per picture height (lpph).

I should have mentioned that my V6000 camcorder was connected to a Sony PVM-2730 video monitor. The connection was S-Video.
The Hi-8 playback deck in the V6000 has a time-base corrector, which is a worthwhile feature particularly if you are recording the playback onto another tape as you intend to do.

To resolve 400 lines per picture height horizontally you would need a TV or video monitor with S-Video inputs of some sort (perhaps via a SCART connector but more usually via the 4-pin mini-DIN connector which has now become associated with S-Video). A reasonably good alternative to S-Video input would be Composite input feeding a “comb filter”. There are some side-effects to using a Comb filter, particularly with PAL and some comb filter designs are more successful than others.

The colour picture tube must of course be capable of good resolution at 400 lpph and many are not.
We have a Sony 14” tubed TV set which has RGB inputs (via SCART) and the picture tube can just about resolve 3.5 MHz, which is 273 lpph. This is not at all unusual. The moral is: just because a TV set has S-video or RGB inputs it does not follow that it can resolve anything like the 400 lpph of SVHS let alone the 500 lpph of DVD!

Alan

Hi Alan,
Many thanks again, for you further help.

* It would be a great help if you could check out the Test Card Resolution on VHS. *

Obviously I can see the benefit of a monitor/TV capable of resolving 400/500 lines especially where your finished work needs to be to a high standard (i.e. non VHS)

For my current needs (i.e., getting the best dubbed VHS standard possible) a higher quality TV becomes a luxury, as I only need to be able to see 250 lines on the finished tape, as do the people who will ultimately be using my tapes, so its important to get the best performance at this level.

However, I can see the added value when your trying to trace a fault or flaw in a system.

Obviously there's a S-Video output connector on my video, but no input on the TV.
My Video's Handbook shows the pin connections for its 2 scart plugs,
One scart has the separate Y/C Out - connections (pins 15/19).
So would the TVs Y/C IN Connections be the same pins ?

In the past it was quite easy to record the off-air test card that was regularly transmitted.
This is not the case today however, are you aware of any test card that is still transmitted ?
and if so when ?
even if its at some unearthly hour, I can set the timer to tape it.

Malcolm.

Hi Malcom,

Scart pinout specs http://www.hardwarebook.net/connector/av/scart.html

If you are interested. I could record some test patterns i.e. Frequency sweep / multi burst from a test signal generator or dubbed from a Digibeta alignment tape to VHS or SVHS for you.

Would this help in your quest for quality

rgds

GG

Hi GG...
Yes that would be a great help if you could do that

Malcolm

Hi,
Does anyone know of a good supplier of the - Industrial SVHS/VHS machine like a Panasonic 7500 or 7600 Series - mentioned earlier by MHP ?

Malcolm

Hi Malcome

TNP Broadcast have 3 Panasonic 7500's available for sale at £350 each. Don't buy them all as I want one!

Hi Malcom

TNP Broadcast have 3 Panasonic 7500's available for sale at £350 each. Don't buy them all as I want one!

Regards

Keith

Thanks Keith,
Do many of you have experience of the quality of performance of these machines, and their value etc.

Malcolm.

Malcolm,

You wrote:
“In the past it was quite easy to record the off-air test card that was regularly transmitted.
This is not the case today however, are you aware of any test card that is still transmitted ?
and if so when ?
even if its at some unearthly hour, I can set the timer to tape it”.

Test cards on terrestrial television are now as rare as hen’s teeth. They are sometimes broadcast for some minutes before the start of programmes but it is anyone's guess when that is supposed to be as most stations appear to run 24 hours a day.

In any case the usual BBC Test card F, excellent though it be, is not much use for VHS testing as the frequency gratings are at 1.5 MHz, 2.5 MHz, 3.5 MHz etc.

The 2.5 MHz (195 lpph) grating is too low to be much of a test and the 3.5 MHz (273 lpph) grating will not be resolved at all as it is too high.

[This was not the designer’s (George Hersee) fault as VHS wasn’t around in the 1960’s and anyhow it was deigned for 5.5 MHz bandwidth broadcast television. (George died last year I understand). As I am sure you already know, it is his daughter Carol playing Noughts and Crosses with the Teddy Bear in the centre circle of the card].

You really need a test card purpose designed for VHS, which has frequency gratings around the 3.2 MHz (250 lpph) region.

I am sure someone (GG?) will know of a source of such a VHS test tape.

Alan

Many thanks Alan (M)

It would have been a different story though if we where discussing the real innovators of home video, the...
The Philips 1500/1700 series !

[ However, I digress and we know how fatal that can be ;) ]

Alan, I don't mean to be a pain, but...

Any news on that Test Card VHS resolution test ?

Malcolm

Hi Malcom,

Checked for VHS test tapes, unfortunatly none of much use. We don't fix many VHS machines anymore just broadcast stuff.

Unfortunatly nearly all our TSG's are SDV, so need to convert from this to Y/C.
However found a sutable one.

Multi burst at intervals of 1/2/3/4/5mhz
and frequency sweep from 1>5mhz with markers.

The 2nd is probably best as you can see better the cut off.
I will do a few different test patterns for you.

If you send your address to ***********.com

I'll get it sorted.

GG

[This message has been edited by GG (edited 18 June 2002).]

Malcolm,

Herewith a report of tests as promised! I do not have two SVHS / VHS machines hence the use of Hi-8 as the “master” tape. I suspect SVHS would be slightly better as the master. I had to use the EV-S9000 to play the master tape as it allows its time base corrector to be switched in or out. On the camcorder it is permanently on (AFAIK).

Equipment used:

Sony CCD-V6000E Camcorder (Hi-8)

Sony EV-S9000E video cassette recorder/player (Hi-8)

Panasonic AG-4700-BY video cassette recorder/player (SVHS)

Sony PVM-2730QM video monitor

Test Chart: EIA Resolution chart 1956

All connections S-Video

(1) Camera section on its own: 430 lines per picture height (lpph). This may well be limited by the video monitor which has a claimed horizontal resolution of 560 lpph. I suspect this figure does not take into account the quasi-Kell factor due to sampling by the CRTs vertical stripe structure. So the monitor is masking the true camera maximum resolution. Moving the camera very slightly laterally relative to the test chart produces only a slight variation in the 400 lpph MTF so the 400 lpph response would seem to be pretty genuine unlike the 520 lpph claimed for some DV camcorders.

(2) Hi-8 first generation recording: 400 lpph

(3) SVHS first generation recording: 400 lpph

(4) VHS first generation recording: 250 lpph with sharp cut-off above this as if caused by an electronic filter.

(5) Hi-8 recorded tape played with time base corrector (TBC) ON into SVHS recorder and then replayed from this SVHS machine with its TBC ON:
380 lpph estimated. Noisier than Hi-8 “master”.

(6) Hi-8 recorded tape played with TBC ON into VHS recorder and then replayed from the VHS machine (actually the SVHS machine switched to VHS) with TBC ON: 250 lpph with sharp cut-off above this. Noisier that the first generation VHS tape but judged acceptable by VHS standards.

(7) As (6) but with TBC OFF on VHS replay. Same 250 lpph but more picture jitter. Probably still acceptable.

(8) As (6) but TBC OFF on Hi-8 “master”. Same 250 lpph. Jitter similar to (7) and probably acceptable.

(9) As (6) but TBCs OFF on both master Hi8 and VHS machines . Still 250 lpph but very noticeable picture jitter. Judged unacceptable for this reason.

Preliminary conclusions:

(C1) SVHS and Hi-8 do have a usable horizontal resolution of 400 lines per picture height (5.1 MHz) as claimed by the manufacturers.

(C2) VHS has a usable horizontal resolution of 250 lpph (3.2 MHz) as claimed.

(C3) A VHS recording made from an SVHS or Hi-8 master tape should yield a horizontal resolution of 250 lpph.

(C4) For all playback a time base corrector is worthwhile. For second generation recordings it is nigh on essential for at least the master player to have a TBC.

Hope this may be of some help,

Alan

[This message has been edited by Alan McKeown (edited 12 June 2002).]

Malcolm,

How did you “calibrate” the test chart width relative to the TV screen?

Most TVs and viewfinders, even in this day and age, are over-scanned, for some unfathomable reason.

My monitor’s scan width and height were carefully set up (by me) to agree with Test card F when I purchased the monitor 12 years ago. They still do.

If your TV / monitor screen is over-scanned then you will be inadvertently incorrectly estimating the horizontal resolution of the camera etc. if you set the test chart horizontal limit triangle points at the screen edges.

The answer to the question as to whether this makes your results optimistic or pessimistic I shall leave as an exercise for the students !!

Alan

There's a suitable test card at the url below, for measuring overscan. The instructions are all in the big document that goes with it.

------------------
[email=alan@mugswell.freeserve.co.uk]alan@mugswell.freeserve.co.uk[/email]
http://www.chromehead.co.uk/testcards.asp

Many thanks...

* Alan (M)
For your in-depth test, I'm still checking out my set-up.

* Alan (R)...
For your info...
I'm unable to access your site !

* GG
I'll get back to you ASAP.

Malcolm

Malcolm,

Even if you managed to download Alan R’s overscan test-card could you actually make use of it?

It is of course in principle ideal for the job of estimating how much overscan there is on your “monitor” .

However, it is no good printing it out on paper and using your video camera to image the printed version to provide a video signal to drive the monitor under test !!

You need to be able to keep the test card in electronic form all the way to the picture tube of the “monitor” under test. This would require some form of digital to analogue video convertor to provide the relationship between 52 microseconds and the time to scan between the 0 % overscan marks on Alan’s test card. The obvious way would be to “drop” Alan’s test card onto the timeline of an NLE programme and play out the card from the timeline via FireWire to a DV D to A convertor. However as I understand it, you do not have digital facilities (hence this thread!).

Alan

Hi Alan (M)

How does, Alan (R), expect you to make use of his test card ?

I dont know, because I have been unable to access his URL, I keep getting the Browser error msg...
"The page cannot be displayed"

But I take your point, I have the converter that allows me to display my PC screen onto tape, would that help ?

Also - GG - has offered to send me a tape with...
"Multi burst at intervals of 1/2/3/4/5mhz
and frequency sweep from 1>5mhz with markers."

Malcolm.

Malcolm,

The “chromehead” server is “frequently inoperative” if my experience is anything to go by.

You would have to ask Alan Roberts as to whether your “computer-screen to video” method would work. I would think that such a conversion would still require some sort of calibration, which sounds as if you might be back where you started from!

GG’s test tape should be of some help. I do hope he means 1 MHz , 2 MHz , etc. which are a billion times higher than the frequencies quoted.... : )

Alan

quote:Originally posted by malcolm samuels:
Thanks Keith,
Do many of you have experience of the quality of performance of these machines, and their value etc.

Malcolm.

i use a 3-machine edit suite based on these machines.
the player heads are worth nearly 800.00 on their own , that's what our last set cost to replace , including time.
would suggest at that price you grab them quickly.

Ha Ha, Alan

Yes I do mean 1Mhz, 2Mhz. It just takes longer to write it like this

BTW The tape is done!

GG

Surely the best test for Malcom, would be if someone who knows what they are looking for... (and has suitable high quality monitor), was to offer to check some of Malcom's tapes of his test card. I would suggest that they should look at his master U-Matic (if they can) and dubbed vhs's and also a SVHS recorded on the camera itself.

That way, a trained eye could see if there is actually a any higher resolution being recorded, but not being resolved by his monitor...... or whether one of his decks is knackered.
Hopefully they would then be able to point the finger at the "weakest link" in the chain....

Sadly I am not that person.... with a standard TV as my monitor... and a very untrained eye to so the viewing, it wouldn't be any better a test than Malcom is already doing himself (in fact my tests would be a lot worse by the sounds of the knowledge that Malcom has)

Any offers.... (come on everyone... 95 replies... and he still has no solution!)

Mike

The overscan test card is primarily for you to put on an NLE as a still, and then view on a monitor. It'll tell you how many lines/pixles you see on it, and therefore how many are lost in overscan. You can send it back to the camcorder and show yourself how much the camera's viewfinder overscans.

If the chromehead site os still down and you want the files, contact m,e at home and I'll send copies by email. Don't all rush at once, it's a 56k modem and I pay for the phone calls.

I once got Bob C to promise that he'd host all that stuff here somewhere, and emailed it all to him. But I can't find it anywhere on the CV site, so maybe he decided against it.

------------------
[email=alan@mugswell.freeserve.co.uk]alan@mugswell.freeserve.co.uk[/email]
http://www.chromehead.co.uk/testcards.asp

Mike,

You wrote:

“Surely the best test for Malcom, would be if someone who knows what they are looking for... (and has suitable high quality monitor), was to offer to check some of Malcom's tapes of his test card.”

Until Malcolm has sorted out his monitor overscan problem by finding out how much overscan is present, Malcolm’s tapes of the EIA Resolution chart 1956 are meaningless.

Alan

Malcolm,

Just as comparison measurements for when you receive GG’s test tape.

It would appear that the eye can resolve detail down to perhaps -20 dB but as Matt rightly pointed out you must not exceed this by using cameras, tape recorders and monitors together, all with falling high frequency responses and expect to still resolve detail which might by that time be 30 or 35 dB down. It does not take much below -20 dB for the detail to be completely lost in the noise especially with inherently noisy media like SVHS and VHS.

Frequency response of my example of Panasonic Video cassette recorder / player AG-4700 E

Test signal was luma Multiburst from the Alan Roberts Multiburst test card, (many thanks to Alan for making such a useful set of test cards available on the internet) played via iMovie NLE via FireWire to DataVideo DAC-1 Pro DV “bridge”. Test signal was taken from luma S-Video output of DAC-1 to S-Video luma input port of Panasonic AG-4700.

Recording tape used was JVC XG-180 (SVHS).

The S-Video luma output of the Panasonic player was measured on an ordinary oscilloscope with delayed timebase facility. The frequency response of the oscilloscope is less than 0.1 dB down at 6 MHz. The terminating resistive impedance at the oscilloscope input was nominally 75 ohms.

Results are given as calculated after allowance has been made for the frequency response of the DAC-1 digital to analogue convertor section which was measured separately.

SVHS response:

Reference Bar 0 dB
1 MHz -1.7 dB
2 MHz -2.5 dB
3 MHz -3.8 dB
4 MHz -7.8 dB
5 MHz -11.6 dB

VHS response:

Reference Bar 0 dB
1 MHz -1.3 dB
2 MHz -2.0 dB
3 MHz -15.8 dB

Hope the above is of some help. No claims are made for great accuracy!

Alan

Hi everyone...
I'll let you know the latest when Ive tried GGs test tapes.

In the meantime does anyone have any feedback on the quality of the following equipment:

Digital Camcorder:
JVC DV300E
JVC DV500E
Sony DSR PD150P
Cannon XM-1

Combi Tape Decks: (mini Dv + VHS/SVHS)
JVC SR VS 20 EK
JVC HR DVS 3
JVC DV SR 30

Tape Decks: (VHS/SVHS)
NVHS 830

Malcolm

Im sorry but if you are making a training video using old analogue equipment then whatever you do you will never get an acceptable quality level especially copying vhs to vhs. Buy digital or anything newer it will be far quicker and easier

Malcolm - Dropping down to my level - I read above somewhere that you have two Panny 200 machines.

Just as a try, ensure that the one doing the recording has its TBC turned off and the other one with it turned on. Even try running the tape through the sending machine first before going throukgh these motions.......

Ron.

Malcolm - dropping down to my level on this subject - you mentioned that you aare using two Panny 200 machines.

When you do your copying do you turn off the TBC on the recording machine and keep the TBC going on the sending machine, accepting that you`re insert or assemble editing?

Ron.

Malcolm - my third attempt to post to you so hope it works this time. You report having two Panny 200 machines. Try leaving TBC on with the sender, and the one on the recorder off. If that`s no good, despite advice above (VG as it is) also try recording with both machine`s TBCs off, ie., VHS only. Desperate times - desperate measures. Good luck.

Ron.

Ron,

I'm sorry if this is teaching to suck eggs. But sounds like your browser is recalling pages from the cache.

Go to Tools, Internet options, settings under temporary internet files and select every visit to the page. This should do it.

rgds

GG

You`re right GG. I should have been up to it earllier - found it this morning but too late to belatedly admit to things.......

Ron.

I compared the images of my MS4 Panasonic camera to images my minidv cam resolves.

Even if you leave out the gulf in actual resolution, the lack of straight vertical lines and color bleed that the MS4 produces would only be magnified by copying. Ie 1 generation look seriously worse.

Could you get a cheap minidv cam (under £500), a firewire card (under £50), a hard drive (under £80), and use either an editing program or Windows own, and produce you VHS copies from there?

Billy

Billwill...
Many thanks for your test !

I was beginning to think the same myself, although I also think that the record quality from SVHS to VHS is causing an added problem...

I tried dubbing a first generation recording (from a friends digital camera) onto my SVHS deck (at VHS) and still got a lot of chroma noise, which was really bad on large areas of primary colours, like Blue and Red.

So, that's why I asked if anyone had any feedback on the quality of the above (5 posts up) equipment ?

GG..
Many thanks, I've now received your tape, but before I can take a look at it, I need to makeup a scart lead from video to TV.

Many thanks guys...

So, Does anyone have any feedback on the quality of the above (5 posts up) equipment ?

Malcolm.

Malcolm,

VHS and SVHS (together with Video 8 and Hi-8) all have noise problems, particularly on areas of saturated colour and especially reds.

First generation recordings might be considered acceptable if you are not at all fussy about quality, but second generation (say SVHS to VHS) pushes the noise into the region which would be unacceptable to many people. What I described as “acceptable by VHS standards” I personally find unacceptable but then I would probably be classed as being in the “fussy about quality” category.

Without objective measurements it is virtually impossible to know what is being described. I have seen a Digital 8 camcorder described as “fully up to broadcast standards”. Probably the writer was sincere in this opinion, however mistaken. That is what Science is all about: a description of the physical world in terms of objective measurements. It has been a spectacularly successful approach.

Unfortunately you have no way of measuring luma or chroma noise, so we have no real way of knowing if your pictures are worse than the norm for the equipment you are using.

If you are prepared to abandon “analogue” and embrace “digital” then many of the problems should vanish (along with a large sum of your money, of course)

For what its worth, here is my opinion (with some objective justification!) on which camcorder of your selected quartet is the best, so long as I am not paying

Of those mentioned, my clear favourite would be the JVC GY-DV500 E.

IMO, this camcorder is in a different (higher) league to the others and is the only one of the four which could reasonably be described as “professional”.

The JVC GY-DV500 E features (uniquely among these four):

(1) Bigger ( 1”/ 2 ) imaging chips for better resolution and sensitivity.

(2) Superior lens. Interchangeable, with proper manual control. Better optical performance. No auto-focus, which, although useful on a “stills” camera is the opposite on a moving-picture camera.

(3) Much better optical anti-aliasing filtration. This is an important factor as aliasing artefacts can be very irritating to watch.

(4) No “image stabiliser”. Image stabilisers are another near-useless feature if your aim is to produce good quality pictures. There is no known adequate substitute for a sturdy tripod.

(5) Adequate mass (about 5 kg) to facilitate good panning action with a fluid pan and tilt head. It is more difficult to achieve a really smooth pan with a very low-mass camcorder.

(6) Higher resolution (CRT) viewfinder.

(7) Generally much better (manual) control over the camera functions.

The obvious downsides are the higher cost (though you are getting more for your money) and the reduced portability compared with the others though none of those mentioned is exactly cheap or pocket-sized.

Alan

I`ll keep mine brief because i haven`t the ability at this moment in time to technically evaluate -

XM1: I don`t consider the sound to be as good as my previous cameras. No AGC. Weak input and not directional as described in the bumph. (They can`t have things both ways surely.) Not a bad picture, but not as good as some others I`ve seen - satisfactory for my purposes and the people I normally deal with. Weighty enough for handheld work in activity scenes. Present model is the third one after the first two had a fault.

Ron.

Alan- I would generally support your choice of camcorder if a pro-consumerwas utterly necessary, but I've a feeling that Malcolm doesn't want to embrace a hefty financial commitment to produce his training video unless he intends to produce a number of comercial future projects.

Malcolm- are you considering upgrading your camera and edit deck with £5/7k worth of professional kit?

I, for instance was unhappy using my MS4 and two svhs consumer decks to produse VHS copies of the theatre shows my drama club did. So I bought a Canon XM-1 and DV500 capture card (total cost £1900) and keep the resolution at approx 500 lines until it outputs on VHS tapes. And I am totlally satisfied with the dramatic improvements- not even counting better titles, transitions, and other computer enhancements like hue, brightness etc.

I don't agree with your point Alan re image stabilisation being a near useless feature. The XM-1 cam has optical image stabilisation and I use it most of the time- It certainly doesn't reduce resolution that electronic stabilization does, and is useful when tripods are not possible- ie on locations where they happen to be an extra thing amongst others to carry.

Hi guys, and thanks for your recent input...

The more I look the more confused I get !

As it seems I've already done all of this once, and at great cost !
My fear is that if I go and buy some new gear, that either...

* It will not solve my original problems...
* Or, I'll simply replace them with new problems...
* Or, make the mistake of buying the 'wrong equipment' and wish in hindsight that I'd bought something else.

It seems to me that no one in this business really has a real clue (or cares) as to what they are actually selling !

The standard cop out (after you've bought poor, or wrong gear) is either, 'that's your problem' or, 'what do you expect for domestic equipment !'

(Even though you asked most of the relevant question before buying the goods)

This last comment was actually made to a associate of mine by JVC, after he'd just bought to SVHS decks that didn't record particularly well.

I am an engineer by trade, I have worked both on the technical side and in sales, and I have always made sure that my customers where given sensible options, sensibly explained to them, with full working demonstration, so they could then make the best decision.

I would have either replaced the goods or refunded my customer money, if they had ever bought anything I had recommended, that did not live upto the job, after I had evaluated their needs, and recommended it.

I can honestly say this never, never happened !

Yes I know that equipment is constantly changing, and more so now then ever before !

But this does not mean that sensible decisions cannot be made, and 'genuine' practical advice given, based on the real needs and expectations of the client.

Alan (M)...
Yes I agree that the - JVC GY-DV500 E - is a good camera and probably the best of the bunch I have mentioned, I have an associate who has this camera and he's very pleased with it.

Billwill...
No and Yes !
No: I don't relish the thought of spending that sort of money.
But I do need to produce a decent quality produce (i.e., final VHS copies)

However, I have now come to the conclusion that I will have to purchase a NLE system + a good digital camera + a good SVHS deck, which can produce good final copies. (which one's are the problem)

Q)
So, I am considering purchasing a NLE system from Siren Electronics, in Manchester.
So... does anyone have any experience of dealing with them ?

Q) Also, the digital camera, I would like the - JVC GY-DV500 E - but feel that I should buy something upto say 2.5K (+vat), and possibly upgrade later if funds allow.

Based on (shop) advice, I was considering - Sony DSR PD150P -
Then...
I have seen that the new - JVC DV300E - at a similar price to the Sony, but it appears to have a better spec...
3 x 1/3rd" CCDs at 570,000 pixels, etc.
It also claims a 700 line StreamCorder features, to upload live etc to the web.
(I don't think that the web feature would immediately be useful, but who knows)
However, does this also mean that the normal camera (camera to tape etc) resolution is 700 lines ?

Please let me know your thoughts guys.

Regards Malcolm.

Malcolm,

If I understand you correctly, you are saying that an “off air” recording made to VHS (on your SVHS recorder) was acceptable (on playback) but a recording, also VHS, made on the same machine but from a DV master tape was not acceptable (when played back on the same machine).

Is this a fair summary of the situation?

I appreciate that the picture content was probably quite different in the two cases making subjective comparison difficult.

Alan

Hi Alan (M)
Yes, but to clarify...

Both recordings have chroma noise, but the off-air (first generation) recording not quite so bad.

Also, the recording on the digital camera (Sony PD150) was good when played back on this camera into a monitor.
But the dubbed VHS copy, when played back, had horizontal chroma noise.

This was probably acceptable on the main content of the recording, but very poor on any large area of single colours, like blue, red etc.

E.G.: When the Sony was stopped (while the vhs tape was still recording) it must have generated its own blue screen, (which was visible in the Sony's LCD Viewfinder, because a completely blue raster was recorded to vhs, and this was terrible.

Also, in this recording, we took a shot of an office chair that was also blue, and that was also noisy, although the effect was not as obvious because the chairs fabric had some texture to it, which helped to mask the noise.

Also, I have played GGs test tape...
i.e.: His SVHS recorded tape played back on the same machine.
And, the colour bars have the same kind of noise, which is more noticeable on the red and blue end of the bars.

His frequency sweep of 1 to 5 mhz show a drop-off at about 4.25mhz, also...
Switching my VCR from SVHS to VHS has no effect, i.e. it doesn't reduce this resolution.
NB: this VCR is still only connected to a TV via its RF socket.

What does anyone know about the Panasonic AG-DVC200 Camcorder ?

Many thanks, Malcolm.

Malcolm,

The manually operated VHS / S-VHS switch is only operative in the record mode. The recorded status (VHS or S-VHS) of the tape being played back must determine whether playback is set to VHS or S-VHS and so this is done automatically, overriding any manual setting.

The Panasonic AG-DVC200 camcorder was reviewed by Sue Farrants in the February 2002 issue of “Computer Video” magazine. Her main conclusion was that it is very similar in video performance to the JVC GY-DV500 but that the latter has better audio facilities. The Panasonic camcorder will take “full sized” DV tapes whereas the JVC is “limited” to one hour mini-DV tapes. (As someone who remembers having to reload standard-8 film every two minutes, I am slightly bemused (not to say amused) that anyone should find one hour a significant limitation on a camera!)

Just to pick one reason from several for choosing one of these “Pro” camcorders (as opposed to a Sony DCR-VX2000 / PD-150).
To quote Sue from her review of the Panasonic AG-DVC200:
“We viewed the results subjectively on a professional grade-two monitor. The pictures were as good as we have seen from DV. They were pin sharp and detail was excellent with none of the flicker on edges sometimes seen on digital footage”. I think this is probably a reference to the aliasing problems which are particularly noticeable from the VX2000 / PD-150.

The Panasonic camcorder retails for about £4500 as compared to £3750 for the JVC (both inclusive of VAT). These prices include a basic Fujinon zoom lens which, even if it is not quite the world’s best, is considerably better optically than the lenses on any of the prosumer cameras and much more designed for manual control.

NB: The Panasonic AG-DVC200 is NOT a DVCPRO machine despite what it says in the review. ( I understand this was not Sue’s fault!)
It is a standard DV machine.

There has been quite a bit written on both camcorders in these fora, which are worth “searching”.

You will obviously have to determine whether the VHS colour noise problems you are experiencing are just typical of VHS in general or for some reason worse in your particular case. It would be all too easy to say “get a “professional” VHS recorder and this will solve your problem” : of course it might do. But I would want some hard evidence of improvement before I parted with any cash. In what areas of performance are professional VHS machines better and if they are better, by how much in recognised engineering terms? My suspicion is that you are not going to be happy with any flavour of VHS after seeing what DV can achieve.

Have you considered distributing your training videos on DVD?

Alan

Hi Malcom,

Haven't looked at this thread for a while now, thought I would come back and see how you are getting.

Not too good by the sounds of it

The colour bars at the top of the tape I sent you are 100% bars, which are quite a severe test, and will show up as noisy, especially in the reds and blues.

So far we have been testing the resolution of the Y channel. The chroma on a VHS or S-VHS is much lower resolution, also because of the "colour under" system used in VHS to record the chroma it is inherently noisy.

Perhaps you are expecting too much?

As other people suggested if you recorded in DV and kept the footage in the digital domain until you make the VHS's then the results should be much better. I understand thought this means more money

It was interesting from the frequency response printouts I sent you that the domestic S_VHS gave better results than the semi-pro AG-7700. I checked these results against another brand new semi-pro VCR with the same results, the results were completely the opposite to what was expected.

Another quite useful link I found about keeping VHS resolution reasonable while copying.
http://www.trecinc.org/Workstations/ClearView_Workstation/High_Resolution_Tape_Copy.htm

The nearest thing to what they suggest which might be in your price range is the GTH ACE
http://www.gthelectronics.com/controlc.htm

However, I have never used one and don't know what the results are like, although I have heard people commenting on how good it is in other threads here. This little box also claims to be a standards converter, but I don't believe such a small box can do a good standards conversion for the price, especially when good Pro converters cost upwards of £8,000.

As it is effectively a TBC apart from the detail enhancement etc, it will replace the syncs with reclocked stable ones which will also improve things a little.

rgds

GG

[This message has been edited by GG (edited 01 July 2002).]

Thanks Alan and GG...
Just a quickie, I have to go out.

Your points noted...

I have now decided to buy a digital camera, (the question is which one ?)
and keep everything digital until the dub to VHS.

I first thought the Sony PD150 then
The JVC DL500, and now
Prestons of Malvern say the Panasonic AG DVC200 is a better buy then the JVC...
But its dearer of course !

Confused, I think so ?? (what's my name ? )

Malcolm.

Hi Malcom,

In my opinion the Sony PD150 is a much better camera (BTW it's DV-CAM, not DV),
which is also good, although quality wise DV-Cam is no better than DV, it is much more robust.

As I wrote here why: http://www.dvdoctor.net/cgi-bin/ubb/Forum8/HTML/001710.html

You will probably find that JVC cameras are not very popular on this board. I also know some people who haven't been too impressed with JVC. They tend to be a bit plasticy too.

rgds

GG

Hi...
Many thanks GG...

Now I'm really really confused !
I've read your link, and if I understand correctly...

On the one hand...
You say the PD150 is a better camera then the - JVC DL500 and Panasonic AG DVC200 etc.
Primarily because its the DVCAM standard, and not the DV standard.
Which makes it more robust...
But despite this, there's no difference in performance between DV and DVCAM !

And to quote Alan (M), who basically says the reverse, i.e....
["Just to pick one reason from several for choosing one of these “Pro” camcorders (as opposed to a Sony DCR-VX2000 / PD-150).
To quote Sue from her review of the Panasonic AG-DVC200:
“We viewed the results subjectively on a professional grade-two monitor. The pictures were as good as we have seen from DV. They were pin sharp and detail was excellent with none of the flicker on edges sometimes seen on digital footage”. I think this is probably a reference to the aliasing problems which are particularly noticeable from the VX2000 / PD-150."

"The Panasonic camcorder retails for about £4500 as compared to £3750 for the JVC (both inclusive of VAT). These prices include a basic Fujinon zoom lens which, even if it is not quite the world’s best, is considerably better optically than the lenses on any of the prosumer cameras and much more designed for manual control."]

NB: Prestons want £4500 + VAT (not £4,500 inc) for the Panasonic AG-DVC200.

Tell me, have any of you guys ever worked for secret intelligence, torture division

Hi Malcolm,

Must be quick as I need to dash,

Sorry to confuse, I wasn't completely clear I think.

End result, DV and DV-cam are no different. However The PD-150 has a better camera front end than the VX2000, so overall the results will probably be better from the PD-150. I can't comment though as I have never had the pleasure to compare the two.

If you speak to sony they will say that the PD-150 is a semi-pro and the VX2000 is consumer.

Pro cameras with VTR are BetaSP/DigiBeta/BetaSX and DVCpro etc....

Whatever you say DV and DV-CAM are in the consumer/semi-pro bracket. That doesn't make them crap though

I also can't comment on the Panasonic AG-DVC200, but the CV review was quite favorable if I remember.

rgds

GG

Malcolm,

I was not aware of any significant difference in the camera front ends between the Sony VX-2000 and the PD-150. Perhaps GG will explain what the differences are and why they would result in a better picture from the PD-150.

I understand that the BBC use VX-2000s (with some audio input modifications). I think it is unlikely they would choose these in preference to the PD-150 if the latter gave a superior picture.

Both the VX-2000 and PD-150 have different imaging chips to the earlier VX-1000. Both the newer cameras have about 6 dB less noise (at low light levels) than the VX-1000.

Also the VX-1000 had (I think) 760 picture imaging elements in each horizontal row (of the imaging chips) whereas the VX-2000 / PD-150 have 720. The VX-1000 had an optical anti-aliasing filter whereas the VX-2000 / PD-150 do not (AFAIK).
The nett result is that the VX-2000 / PD-150 have better detail resolution than the VX-1000 (because it is not reduced by the gradual in-band roll-off of the anti-aliasing filter) but at the expense of suffering more (than the VX-1000) from aliasing artefacts.

Alan

Umm,

Must have been thinking of the VX-1000 then

As I said "I can't comment though as I have never had the pleasure to compare the two."

Alan, who said the beeb only use VX-2000?

Although for audio, correct they do use a beachbox to convert the Camera mic Jack to XLR etc. These boxes are pretty standard and will fit on the DSR-PD150 and VX’s. You can also get a range that fit on the Canon XL/XM cameras

The Beeb actually do use PD-150's, VX-1000 and VX-2000, usually for things where a full size pro camera isn't practical or for news, where top quality doesn't seem to be quite so important. Although they probably don't have too many VX-1000 left now.

No doubt the Panasonic AG-DVC200 seems to be a pretty impressive DV camera from the specs, if you can afford one, I should expect you wouldn’t be disappointed.

Rgds

GG

Malcolm,

Regarding your “nota bene” on the price of the Panasonic camcorder.

The H Preston web site: http://www.hpreston.co.uk/

gives their price for the Panasonic AG-DVC200 as £4500 including VAT
and their price for the JVC GY-DV500 as £3795 including VAT.

Sue Farrants’ review also quotes £4500 including VAT for the basic Panasonic AG-DVC200 package from H Preston.

Perhaps the price you have been quoted is for a different option package?

Alan