Making Movies with the Apple iSight
Subject:   Video and sound not in sync.
Date:   2005-07-23 00:32:40
From:   Holland_Jim
Response to: Video and sound not in sync.

What I'm discovering is pretty simple:

* You lose audio sync under firewire
* You don't when you use analog audio

I don't know about USB-audio, but the Firewire delay is very troubling. I was using a JVC video deck to stream training tapes internally to our company and the audio always crawls out of sync, noticeably after a few hours.

What's odd is that starting the stream, the audio is in sync. Then the audio drops out as the video continues and it picks up in a few seconds completely delayed.

I'm using the LAN settings for audio and video and distributing an sdp file to the clients, who are all running QT7. The video is encoded on a dual 2.3 Ghz G5 with 2.5GBs of RAM (so the worst it gets is 50% busy) and then is streamed and served by a linux-based DSS server outside our DMZ. It works beautifully, even through firewalls. I just wish it would stay in sync!

Firewire audio seem to be the culprit.