[FFmpeg-devel] [PATCH 3/6] lavc: deprecate -ab as part of FF_API_OLD_AVOPTIONS.

Ronald S. Bultje rsbultje at gmail.com
Mon Aug 17 19:38:19 CEST 2015


On Mon, Aug 17, 2015 at 1:12 PM, Michael Niedermayer <michael at niedermayer.cc
> wrote:

> On Mon, Aug 17, 2015 at 11:52:16AM -0400, Ronald S. Bultje wrote:
> > ---
> >  libavcodec/options_table.h | 2 ++
> >  1 file changed, 2 insertions(+)
> googling for
> ffmpeg "-ab"
> has 332.000 matches
> ffmpeg "-b:a"
> has 64.100 matches
> this patch is simply a bad idea

So, there's a few practical problems here. A) if we remove flag/mask from
the set_defaults calls (other patch in this set), the audio is also used
for the video ones (since we ignore media type), and thus we use (after
FF_API_OLD_AVOPTIONS is 0) the audio bitrate as default for video also.
That's bad, and causes some fate failures. We can workaround that by
inverting the ordering of these two, but then, the general one _always_
(even before FF_API_OLD_AVOPTIONS=0) takes precedence over the audio one,
so all fate results without explicit bitrate change from ab=128k to
ab=200k. (I'm working around that by making each fate test set bitrate
explicit where relevant.)

Alternate suggestion: I don't mind if -ab gets a workaround in ffmpeg.c,
but I'd like to remove it from the libav* code.


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