Comments

TGS wrote on 8/12/2008, 9:50 AM
Which type of mpeg 4? I haven't seen the problem using MainConcept AVC/AAC(mp4)
I have heard somebody else complain about DivX, if I remember right.
Derm wrote on 8/12/2008, 10:08 AM
Hi ,
Its Main Concept AVC/AAC.
Derm wrote on 8/12/2008, 10:33 AM
This is strange , if i import the rendered file back into the Vegas the sync is fine, but when it plays in QT player the sync is off.
TGS wrote on 8/12/2008, 2:04 PM
I have no answer.
I've uploaded videos using MainConcept mp4 to YouTube and it seems fine. I try not to use QT, but I also am not doing any HDV, so I haven't tried any mp4s using QT.
I've sworn that my stand alone DVD players play audio just a hair fast, compared to software players and Vegas. Mpeg 2 files. But haven't been able to test this on too many besides the few I own. And it's very close.
Simonm wrote on 8/12/2008, 3:11 PM
This is strange , if i import the rendered file back into the Vegas the sync is fine, but when it plays in QT player the sync is off.



Is it off at the start, or is it right to begin with and then drifts, getting progressively worse?

If the latter, you may fix it with 'frame interleave' in the video settings of the renderer, or, if that gives jumpy playback, some interleave setting that's a short time interval (1/4 sec should do it, which I think is the default).

IIRC, MP4 is a container format, and so will accept a variety of CODEC settings (video formats). For heavily compressed formats such as FLV and some formats in QT (another container format, which includes everything from non-compressed HD downwards!), the sound and vision aren't locked at all. The player just starts them together and hopes! As a consequence you're at the mercy of the decoder.

I recently had this with FLV (Flash) and YouTube's transcoder. Stuff in perfect sync here was 2% adrift after 4.5 minutes! That's a lot. Interleaving solved it entirely. I think it intersperses the audio in blocks, so that, as the file is read in sequentially to the decoder, it is forced to do only small chunks of each at a time and sync thus can't drift too far out.

HTH,

S
Derm wrote on 8/12/2008, 3:27 PM
Hi,
Thanks for your reply. I am beginning to think also that QT is the problem however I dont see any option in the render settings under mpeg 4 to alter the interleave.

Derm
Simonm wrote on 8/12/2008, 3:45 PM
"I am beginning to think also that QT is the problem however I dont see any option in the render settings under mpeg 4 to alter the interleave."

Not with Vegas' supplied MP4 codec, but you can do it in FFDShow.

On my system it shows up as an available codec when I choose AVI output, and I can then go in and configure it to do MP4 in the video tab. The output file is still suffixed AVI, but that doesn't seem to be an issue!

FFDShow is open source from SourceForge.

Forgive my curiosity - why not go straight to QT from Vegas. I haven't tried it, but is there some reason why? Do you get better results via MP4?