Can't render to MP4 w/o audio going out of sync

smhontz wrote on 7/24/2012, 2:15 PM
This is driving me crazy. I can take a clip straight from my Canon XF 305 (MXF file format, 1920x1080 24p, 48K 16bit audio) and plop it into a project with the same settings. (The Vegas Explorer identifies the file as 23.976 p, so my project settings are the same.)

When I try to render it to MP4, using either the MainConcept or Sony template, the audio is always out of sync with the video. Not just a little, but a lot.

I'm using Frame Size 1920x1080, Profile High, Frame Rate 23.976, don't have either "Allow source to adjust" boxes checked, Constant bit rate of 10M, render using CPU only, Progressive download, Audio: 48,000, Bit rate 384,000.

Any suggestions?

Comments

smhontz wrote on 7/24/2012, 2:28 PM
Forget to mention this is in Vegas 11 64bit. Build 683
MUTTLEY wrote on 7/24/2012, 2:44 PM

Is the audio from the clips or is the audio from another source?

- Ray
Underground Planet
John_Cline wrote on 7/24/2012, 3:37 PM
What are you using to play back these files? If you're using the Quicktime player, then that's your problem, not Vegas.
PeterWright wrote on 7/24/2012, 8:15 PM
I can confirm John's point - I had the same symptoms a while back, and downloading and using the free VLC Player showed me that what appeared OUT in QTPlayer was in fact IN.
Grazie wrote on 7/24/2012, 9:52 PM
Where does the OP say it is being played in an external player?

G
smhontz wrote on 7/24/2012, 10:13 PM
Thanks everybody for the tip about VLC. I had tried it in Windows Media Player, Media Player Classic, and QuickTime. It doesn't play correctly in any of those, but it does play correctly in VLC.

Shouldn't it just work, though, in Windows Media Player? I thought MP4 was supposed to be some sort of readily-supported standard. I had been rendering to WMV prior to YouTube upload, and never had any issues with that, but thought I'd try using MP4 to compare the quality.
ChristoC wrote on 7/24/2012, 10:26 PM
Steady on.... Expecting things to "just work" is a bit far-fetched
smhontz wrote on 7/26/2012, 12:11 PM
What do you guys do if you want to give someone a rendered file to watch on a Windows machine? Just stick to WMV format? What if you have to give it to someone on a Mac? I was hoping that MP4 would be a universal format that could be played on a PC or a MAC without having to mess with loading 3rd party software, Quicktime, etc.
musicvid10 wrote on 7/26/2012, 2:16 PM
High-bitrate AVC won't play on Quicktime. Neither will VFR, VBR audio, Anamorphic, etc.

Support for this format on Windows is a relatively recent addition (WMP 11, I think). As such, it is a work in progress.

The most common delivery of this format is over the internet (Flash 10 or newer), or on PC with an ffmpeg-based player (VLC, others).

It took years before Mac and Windows finally agreed on universal MPEG-1 compatibility, and they still are not in full agreement on MPEG-2 (it's been over fifteen years), each clinging to their particular versions. In other words, don't hold your breath . . .
MUTTLEY wrote on 7/26/2012, 2:54 PM

smhontz, you never answered my question: Is the audio from the clips or is the audio from another source? I'm a little unclear if the render is out of synch or if its just in a player that it's out of synch. And the reason I ask what the source audio is is because if some files, like mp3's due to their compression, will often become out of synch in a render.

- Ray
Underground Planet
John_Cline wrote on 7/26/2012, 4:08 PM
MP4 requires a fair amount of horsepower to play back smoothly, only newer, higher-powered machines can pull it off well. MPEG2 is pretty processor friendly, so perhaps rendering a 1280x720 MPEG2 program stream at a reasonable bit rate might be an acceptable, mostly universal solution for now.
robwood wrote on 7/26/2012, 5:37 PM
is the audio using VBR for compression? if so...

try converting the source audio to a non-variable codec (uncompressed or constant bitrate), replace the original with it, then render a new mp4.

sometimes VBR gives weird results, especially if you edit it (slice it) before rendering (thats why i sometimes render to a neutral codec to avoid those gotchas.


if not... i dunno.
smhontz wrote on 7/26/2012, 8:38 PM
Ray, for my simplest test case, the audio is just the audio from the original MXF file direct from the camera.

Once I used VLC to play it, everything was in perfect sync. I then played the MP4 render from my original project which had a mix of MXF files with 48k 16 bit audio, and some 48K 16bit wav and 44.1K 16 bit wav files, and everything was in sync - as long as I use VLC to watch it. All other players failed miserably.
smhontz wrote on 7/26/2012, 8:40 PM
No, the original audio was a fixed 48K 16bit, and the render options don't give me any choices as far as VBR or CBR for audio.
MUTTLEY wrote on 7/26/2012, 11:44 PM

Ya know, I didn't think about it till just now reading your last but, even though I use mp4's all the time, my F3 shoots in mp4's and I always render to mp4 for Vimeo and YouTube, but up till about 90 seconds ago I've actually never tried to open one in WMP. I have always had VLC set as the default with mp4's and have for a good coupla years now. Here on my laptop I just tried to open some mp4 source files with WMP and got "Windows Media Player cannot play the file." Then tried to open a finished vid that I had rendered to mp4 a few weeks ago, shocker ""Windows Media Player cannot play the file."

So I suppose if you're getting them to play in WMP at all you're already doing better than I am in synch or not! With that in mind I think that it has nothing to do with your source files, your edit, or Vegas, mp4's and WMP just don't play nicey nice.

- Ray
Underground Planet