[LAU] OT - Audio and Video Synch

[James Stone]

On Fri, Oct 18, 2013 at 11:25 PM, Monty Montgomery <xiphmont at gmail.com> wrote:
> On Fri, Oct 18, 2013 at 5:36 PM, James Stone <jamesmstone at gmail.com> wrote:
>
>> I am wanting to get some audio and video recorded - sample accurately
>> - so there is minimal delay between audio and video, and no drift.
>
> Any camera will give you this if you use the audio input on the
> camera.  Or do you mean you need to record to some other device and
> sync later?  If the latter, you're in for a world of pain.  The clocks
> will drift unless you're using a shared clock, and that's a whole
> different class of professional equipment....
>

OK - that's encouraging at least!

>> Can
>> any format do this?
>
> All of them.  The trouble people usually have is software that handles
> the sync incorrectly (or doesn't really try to handle it at all.  If
> it's based on ffmpeg.... yeah 'all bets are off').
>
>> 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)?
>
> Just about any camera made.
>
>> Secondly, I am wanting to intentionally shift the audio timing so it
>> may be 5ms/10ms/50ms/100ms or more out of time with the video. Do you
>> have any suggestions on software which will do this?
>
> Any NLE will do this.  I use Cinelerra, but I'd urge you not to :-)
>
>> Lastly, do any of you know any research about the limits of human
>> perception with these kinds of things?
>
> You'll not hit the limits of human perception in video-- even 10 bit
> isn't quite there, and you ca always get closer to see more
> resolution.

I meant in terms of timing shift of audio vs video?

James