[FFmpeg-devel] headers for gapless playback

[Tomas Härdin]

tis 2019-11-19 klockan 19:16 +0000 skrev John Kaplan:
> Hi Guys,
> 
> We just did some research on gapless playback across multiple client
> devices, and could not find support for adding gapless metadata
> headers in ffmpeg. Our interest is specifically in AAC/MP4, and we
> ended up shifting to the fdk-aac package, which exposes options for
> adding moov/edts/elst headers (which are the ones we used) as well as
> iTunSMPB.
> 
> So, I wanted to open a discussion with the team on ffmpeg support for
> gapless metadata.
> I’m not sure if you guys have discussed before, so here are a few
> opening questions to get me up to speed…
> 
> 
>   1.  Does ffmpeg support addition of gapless metadata in any form
> currently, and we missed the doc as to how to specify it?
>   2.  If not, have you discussed previously? If so, what were the
> results? (I.e. rejected as evil, put on roadmap but in future,
> currently in development, etc.)

Something very similar to this is being discussed in 
https://trac.ffmpeg.org/ticket/8366

>   3.  If support is still in the future, would you be open to me
> contributing a patch that implements it?

Yes please

I think opening a generic ticket for this would be a good move. Having
the ability to trim essence would be very useful. Then we could also
remove that godawful hack in mov.c as well, hopefully. There's more
than a few formats that need some "warm-up" data or that leave a few
frames of garbage at the end of the file, like all block transform
audio codecs

/Tomas