[LAU] OT - Audio and Video Synch

[Rick Green]

On Fri, 18 Oct 2013, James Stone wrote:

> Hi everyone,
>
> I realise this is not strictly linux audio related, but I guessed that
> the most likely people to be able to answer this would be on this
> list.
>
> I am wanting to get some audio and video recorded - sample accurately
> - so there is minimal delay between audio and video, and no drift. Can
> any format do this? Do you have recommendations about how to record a
> file which will play back with perfect audio and video sync on all
> players (file size is not an issue)?

I have never done this, so this is the results of my research, not 
experience:
   If you have the bucks, you can get hardware clock generators which 
produce both wordclock (48k seems to be standard for DVDs) and SMTPE 
timecode for the video, derived from the same oscillator.
   There is also a technique to take the SMTPE timecode, which is a digital 
datastream, encode it with a modem into audio tones, and record it to a 
separate track on your audio recorder, in parallel with your other audio 
tracks.
   In the editing suite, this smpte track is demodulated and used to 
synchronize the video with the audio.

...All this requires hardware that I can't afford.  I record the video and 
audio separately, then sync them manually when editing.  I've been lucky, 
and the drift hasn't been noticable over the max 2-3min scenes I've worked 
with.

-- 
Rick Green

...I live in the hope that one day the fine line of distinction between
genius and insanity will be decided in my favor.