[FFmpeg-devel] [PATCH] ffmpeg: remove unused and errorneous AVFrame timestamp check

[Hendrik Leppkes]

On Tue, Oct 4, 2016 at 1:23 PM, Michael Niedermayer
<michael at niedermayer.cc> wrote:
> On Tue, Oct 04, 2016 at 08:41:42AM +0200, Hendrik Leppkes wrote:
>> On Tue, Oct 4, 2016 at 4:05 AM, Michael Niedermayer
>> <michael at niedermayer.cc> wrote:
>> > On Sat, Oct 01, 2016 at 04:15:45PM +0200, Hendrik Leppkes wrote:
>> >> Decoders have previously not used AVFrame.pts, and with the upcoming
>> >> deprecation of pkt_pts (in favor of pts), this would lead to an errorneous
>> >> interpration of timestamps.
>> >
>> > I probably misunderstand the commit message but
>> > If code is changed in a user application that cannot really lift
>> > some blockage from changing a lib.
>> > a lib can only change in an incompaible way with (deprecation and)
>> > major version bump.
>> >
>>
>> The lib never did what this code suggests it did, not that I remember
>> (so at least not for a long long time).
>
> release/2.0 with
>
> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> index 29d5492..57c8d50 100644
> --- a/libavcodec/utils.c
> +++ b/libavcodec/utils.c
> @@ -2008,7 +2008,7 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
>                  avci->to_free.extended_data = avci->to_free.data;
>                  memset(picture->buf, 0, sizeof(picture->buf));
>              }
> -
> +av_assert0(picture->pts == 0 || picture->pts == AV_NOPTS_VALUE);
>              avctx->frame_number++;
>              av_frame_set_best_effort_timestamp(picture,
>                                                 guess_correct_pts(avctx,
>
> causes many tests to fail, indicating that AVFrame.pts was set for
> several video decoders, the ffmpeg code is audio decoder specific
> and i failed to find a case where it was triggered, i tried IIRC 3
> or so checkouts from the past
>
> so AVFrame.pts was maybe never set for decoding audio but it was set
> for video

Can you extend the test to add "|| picture->pts == picture->pkt_pts"?
Because thats what it would be set to after the merge. A quick check
in the 2.0 code base looks like some decoders did set that, but to the
exact same value as pkt_pts (which is what the merge is proposing
right now as well)

- Hendrik