[FFmpeg-devel] [RFC] Reviewing merges

[Aaron Levinson]

On 4/23/2017 7:07 PM, Michael Niedermayer wrote:
> Hi all
>
> Should changes ported from libav (what we call merges) be reviewed
> before being pushed?

I've asked about this on IRC (#ffmpeg-devel).  The overall consensus 
there, at least at the time I asked it, is there is an expectation that 
such changes have already been properly reviewed for libav, so they are 
likely to be okay for ffmpeg, and while some issues have crept into 
ffmpeg as a result of these merges, the merge process has gone smoothly 
overall.

As the code bases diverge more and more, reviewing ports from libav 
would be nice, but based on the rate at which patches posted to 
ffmpeg-devel are reviewed, I think that could overload the code review 
resources on ffmpeg-devel.  Plus, the expertise may not exist to 
properly review some of the ported changes on ffmpeg-devel.  For 
example, I submitted a patch to fix a bug with QuickSync interlaced 
video to ffmpeg-devel on 4/13/2017.  The change mostly reverted some of 
the QSV code in ffmpeg back to an earlier state.  Interlaced video QSV 
encoding used to work in ffmpeg, but this was broken in October 2016 as 
a result of a merge with libav.  However, I was asked to submit the 
patch to libav instead because QSV development is more active on 
libav-devel.  I did that, and the patch finally made it into libav 
today.  And, my hope is that it will be merged into ffmpeg--that is, it 
seemed like the most readily available path to getting this code into 
ffmpeg was to contribute it to libav first.  But, if this patch has to 
pass yet another round of code reviews, code reviews that weren't 
forthcoming in the first place on ffmpeg-devel when I originally 
submitted the patch, then that could be problematic.

Aaron Levinson