[mythtv-users] Merging different video/audio tracks

[Nick Rout]

On Wed, Jun 2, 2010 at 11:43 AM, Andrew Gee <andrew at andrewgee.org> wrote:
> Hi all,
>
> I have a multiple tuner setup, and am looking to be able to merge
> recordings I make into a single video file.
>
> I'm recording from freeview DVB-T in the UK.
>
> I record a Formula One motor race from the TV, when I'm not able to
> watch it live. The BBC broadcast a TV version, but you are able to
> listen to the commentary the BBC put out over the radio instead, using
> the red button, which I prefer. But I don't know how I'd record this.
>
> I can record the radio channel and tv channel at the same time, and
> would like to know if there's a way to easily merge them together. The
> TV coverage starts before the Radio coverage, so both streams won't
> start at the same time.
>
> Is there any way to achieve what I want, so I end up with a video file
> that has more than one audio track, synced to the right point?
>
> Hopefully I haven't been too confusing. I've been confusing myself.

With F1 you shouldn't have lipsync problems as such, more
"exhaustgrowlsync" - in other words a few milliseconds out of sync
will probably not matter.

My suggestion, and it is rather manual, is to open the video stream in
avidemux, then add in the audio only stream (you may need to use
something like projectx to demux the audio stream out of it's
container first).

Then you need to play with the audio delay until you get it right,
then use copy for both audio and video and save the file back to the
hard drive.

Obviously if you know they were in sync you could do it via a script,
but you really need human intervention to sync up the audio.