[mythtv] Decision on FFmpeg repository

[David Engel]

On Thu, May 17, 2018 at 10:52:26AM +0200, Jean-Yves Avenard wrote:
> Hi
> 
> > On 17 May 2018, at 12:49 am, David Engel <david at istwok.net> wrote:
> > 
> > Some background.
> > 
> > The main reason we are even considering an ffmpeg update so soon after
> > our last one is to support MediaCodec on Android.  We must go to at
> > least ffmpeg version 4.0 to get that.  Our likely only other
> > alternative for that is to write our own MediaCodec support and I
> > doubt anyone wants to do that.
> > 
> > Peter and I have had discussions regarding our MediaCodec support with
> > one of the ffmpeg developers.  I think he is actually the main
> > MediaCodec person at ffmpeg.  He has already pointed us to some
> > significant, MediaCodec changes that have been committed to master
> > with strong hints there are more to come.
> > 
> > So, we can either use the stable, ffmpeg 4.0 branch with reportedly
> > still deficient MediaCodec support or deal with potential instability
> > and evolving APIs in the ffmpeg master branch.
> > 
> > One other complicating factor is the ffmpeg developer has expressed
> > interest in helping us get some of our changes accepted upstream.  I
> > don't know how well that would go over if we don't use master and
> > consequently aren't able to help test their integration.
> 
> That’s all good, but then that means that support for MediaCoded in FFmpeg is experimental anyway.. Do we want that in our release so soon?
> 
> Are we willing to make everything unstable (from an API point of view) just to have support for something experimental that we didn’t support up to now anyway?

Of course we don't want to intentionally break other things, but in
case you haven't noticed, the Android port is the *only* significant
work being done right now.  IOW, there is no other work to be
destabilized for the time being.  If any other work does comes up and
is affected, we can move one effort or the other to a branch.

> If you ever ask a developer what version of his you should use, of course he/she’s always going to tell you to use the latest and greatest, luckily most team have a release manager :)
> 
> 4.0 was a snapshot of ffmpeg done not even a month ago. By the time we’re ready with Peter’s change anyway, 4.1 would be out. FFmpeg make release frequently, when they are confident current master is in a stable state.

We're, well, mainly Peter, are ready to start now.  If we wait for
ffmpeg 4.1 and it changes as much as you expect, wouldn't we have to
start over again?  In a sense, we're trying to get ahead of the curver
and targeting for 4.1 now.  Note that I don't think anyone is
proposing to closely track ffmpeg master forever.  After the
MediaCodec support, I expect we'll go back to updating to newer ffmpeg
versions on an as needed bases.

David

> WIP on a particular feature rarely ever qualify.
> 
> Anyhow, not that I’m much involved these days to have much weight on any decisions...
> _______________________________________________
> mythtv-dev mailing list
> mythtv-dev at mythtv.org
> http://lists.mythtv.org/mailman/listinfo/mythtv-dev
> http://wiki.mythtv.org/Mailing_List_etiquette
> MythTV Forums: https://forum.mythtv.org

-- 
David Engel
david at istwok.net