mp4 render (SONY and MainC,).. audio out of sync

gilles007 wrote on 1/11/2012, 1:13 PM

This has occurred with two clients now. I hope someone can assist.

I render my footage as an mp4, (HD 1280x720) and I can view the resulting 10 minute video perfectly using Quicktime

However, on my clients' PCs.... the audio is out of sync, ( also using Quicktime to view)

I tried adjusting the audio of the template' audio sample rate from 48,000 hz to 44,100 thinking that may be a problem but this did not change a thing.

What could be the problem?

Gilles

Comments

musicvid10 wrote on 1/11/2012, 8:17 PM

It's not the audio sample rate. That all takes care of itself.
High video bitrate will cause audio sync issues on consumer systems.
Post your rendered media specs as reported by MediaInfo.

Also, Quicktime is notorious for hogging system resources. Do they also report sync problems when viewing in VLC?

gilles007 wrote on 1/11/2012, 8:49 PM

Thanks,

Haven't tried on VLC yet. But on my 2 pcs here, the QT looks good. on two client PCs, it's out of sync.

here are the specs of the mp4 as revealed by QT...
movie fps 29.97
play fps 29.97
data rate 8.05 mbits/sec
size 1280x720
AAC, stereo 48,000 khz h.264

I hope this helps.

musicvid10 wrote on 1/11/2012, 8:56 PM

Halve the bitrate to 4Mbps and see what they get.
Quicktime isn't exactly at the top of the heap of Windows players.

gilles007 wrote on 1/12/2012, 5:57 AM

Thanks musicvid,

However, QT is the most trusted mp4 player, wouldn't you agree? It's a challenge and somtimes not possible to ask a corporate client to install 3rd party players (VLC) on their PC. A marketing mgr typically won't do it and often, the IT dept won't do it either.

I'll try the "halfing" the bitrate trick.

I"ve also seen issues where a client sees audio/video sync problems when the mp4 is uploaded to Youtube, which leads me to conclude it's an issue in the rendering, not the player.

any thoughts?

Thanks again for your interest in trying to solve this.

Chienworks wrote on 1/12/2012, 9:18 AM

The version of Media Player bundled with Windows 7 blows the pants off of the QuickTime player for MP4 playback. Motion is smooth and clear, no sticking. I think the image quality is better too. And it's just a nicer piece of software to use than the QuickTime player is.