H264 or Mpeg for Bluray

MPEG4 twice as efficient as MPEG2.

22Mbit MPEG4 H.264 is same approx quality as 40bit/s MPEG2.

MPEG2 encodes faster in software but since you are decoding from AVCHD it'll still take a while.

Appreciate that Gavin, thanks

If you're finding the encoding to H264 to be very slow, and you have a CUDA card in your computer, you may find the whole process gets speeded up by exporting to H264 from the Premiere Pro timeline, and then taking the encoded file into Encore and telling Encore not to transcode it. Reason for this is that the H264 encoding is speeded up by CUDA when exported from PPRo timeline, but CUDA doesn't come into play when encoding in AME/Encore.
More info on all this on Adobe website and at http://ppbm5.com/index.html
HTH
Mark

I know that MPEG4 based codecs are much more efficient than MPEG2 at low data rates, but unless the codec employs all the tools, doesn't the difference get less as the rate is increased. Surely, MPEG4 without most of the tools is not much different from MPEG2 anyway.

Steve

Probably right Steve - but within the confines of a 25GB Blu-ray disc H.264 may be the only option.

Yes, disk space...hmm but I found it's only worth going to h264 if disk space is critical. I use a Firecoder Blu card to produce m2ts and encode at 22Mbps bitrate. For most purposes the output is good enough, yeah but it doesn't compare with a 35Mbps MPEG2 version! Textures such as grass or tiled roofs on AVC can be perfect one moment then blocky the next.

Then again quite possibly the FCB card doesn't use all the "tools" that Steve talks about, however it's fast and time is money, a hour timeline is converted in only 35 minutes.

For absolute quality where it's really imposssible to tell the difference from the original :cool: I have recently been experimenting with x264. It does mean exporting an intermediate file in Canopus lossless to feed it but wow, this is surely some compression format for quality, just a shame about the huge render times so I am only using this for special jobs right now where an overnight render is worth it.

Quite right that MPEG4 without the clever bells and whistles is just MPEG2. That's why we can't be definite about the performance of MPEG4, it all depends on who wrote the coder and how much of the clever stuff is in there. And it's why the broadcasters are continually getting new software into their coders, to up the quality or reduce the bitrate, or both.

Currently, the best MPEG4 uses a little over 50% of the bitrate of MPEG2 to achieve visually similar results. So, when you get stuck for space, MPEG4 is the way to go, provided you've got a really good coder.

A strange observation.... the file size of a file rendered to MPEG4 is roughly the same as that to MPEG2.

So, when I FTP my news vision, there is no time saving...

(Vegas Pro, with Mainconcept encoder)

I'm pretty sure that Edius makes an H264 encode for Blu-ray by default, straight off the timeline - if that's of an consolation Colin.

Ben, if you tell the coder to code at a specified bitrate, that's what it'll do, irrespective of the coder (so the files will be the same size). The trick is to work out (either by trial and error or by asking for advice) what the effective ratio is between MPEG2 and MPEG4. But, even when you've arrived at that ratio, you'll find that it changes with bitrate (i.e. the savings ratio is highest when the bitrate is lowest, if that makes sense).

Of course, it could be that your MPEG4 coder doesn't have many of the latest bells and whistles, so doesn't provide much of a saving anyway. The broadcasters upgrade their MPEG4 transmission coders every few months, as incremental improvements arrive. This is a dynamic business.

I might be about to spout total rubbish here, but I'm sure I recall it being said in the past that one thing in favour of AVC-HD is that codec-wise it is compliant with Blu-Ray? So whilst it may need authoring, shouldn't need transcoding. Is there an option to author without a transcode?

It will depend on the route through Edius - if the footage is being transcoded for ease of editing, the above is irrelevant, but if you are natively editing AVC-HD, then it should be possible to just re-render around the edits and leave the bulk of the material as original - theoretically.

As far as bitrate/quality versus MPEG2 goes, then I'd agree with others who have said that MPEG4 should provide better quality at the same bitrate than MPEG2, but it depends on individual coder. That tends to be more true for cameras than what is being talked about here. The difference is that cameras have to encode in real time - that's not true of an NLE. Hence even with a relatively lowly PC it's still possible to use many bells and whistles - just expect the encode to take a long time! Broadcast encoders may use many bells and whistles AND (obviously) work in real time - but cost many times the average prosumer camera!

Quite right, MPEG4 uses H.264 coding, which is the official HD coding for BluRay. If the footage is just being dumped to BluRay, then the camera-original footage should play, but if there's any processing needed, then it'll have to be transcoded somehow. Edius is good at coding for BluRay, directly from the time line, but, unless the footage is totally unmodified, it'll have to be re-endoded anyway. Simple edits are probably ok, because it leaves only broken GoPs, which H.264 should be able to cope with, but that assumes that the final player can cope with it, not just the BluRay software itself. I wouldn't like to risk it.

Thanks Tom. I have Edius, but have not installed it on the new laptop yet. Must give it a try. Its times like this that I wish I had archived all my personal footage as I gathered it, there is so much of it, even some old VHS footage from the very early eighties. That, should embarass the kids this christmas.

Colin, get Edius up and running, it'll solve all these problems in one go.