[FFmpeg-devel] [PATCH] avutil/frame: fix av_frame_copy for unknown layouts

[Paul B Mahol]

On 1/30/17, wm4 <nfxjfg at googlemail.com> wrote:
> On Mon, 30 Jan 2017 08:47:49 +0100
> Hendrik Leppkes <h.leppkes at gmail.com> wrote:
>
>> On Mon, Jan 30, 2017 at 8:40 AM, wm4 <nfxjfg at googlemail.com> wrote:
>> > On Mon, 30 Jan 2017 01:37:02 +0100
>> > Marton Balint <cus at passwd.hu> wrote:
>> >
>> >> I wonder how unknown layouts ever worked without this?
>> >>
>> >> Signed-off-by: Marton Balint <cus at passwd.hu>
>> >> ---
>> >>  libavutil/frame.c | 2 +-
>> >>  1 file changed, 1 insertion(+), 1 deletion(-)
>> >>
>> >> diff --git a/libavutil/frame.c b/libavutil/frame.c
>> >> index c2f5509..a08e0c5 100644
>> >> --- a/libavutil/frame.c
>> >> +++ b/libavutil/frame.c
>> >> @@ -725,7 +725,7 @@ int av_frame_copy(AVFrame *dst, const AVFrame *src)
>> >>
>> >>      if (dst->width > 0 && dst->height > 0)
>> >>          return frame_copy_video(dst, src);
>> >> -    else if (dst->nb_samples > 0 && dst->channel_layout)
>> >> +    else if (dst->nb_samples > 0 && dst->channels > 0)
>> >>          return frame_copy_audio(dst, src);
>> >>
>> >>      return AVERROR(EINVAL);
>> >
>> > The original code was written with the assumption that only channel
>> > layouts exist in the AVFrame. And the Libav API follows that. This
>> > patch will probably break Libav API users (or those who want to stay
>> > compatible to them) some more.
>>
>> The copying code would have failed anyway if channels was 0 and not
>> copied anything, so it doesn't break anything that worked before -
>> except that it returns an error code now properly indicating the
>> failure.
>
> Hm, ok then.
>
>> In any case, we've decide quite a while ago to forego any illusions of
>> API or  ABI compatibility, because its impossible to guarantee it
>> anyway.
>
> We still have API compatibility. The channels issue is one of the
> only things that work radically different from Libav. But it looks like
> this was broken long ago and we probably don't need to bother to fix it.

The issue should be fixed, patch LGTM.