[FFmpeg-devel] [PATCH 2/3] ffmpeg: use new decode API

[Marton Balint]

On Fri, 30 Sep 2016, wm4 wrote:

> On Thu, 29 Sep 2016 23:35:49 +0200
> Michael Niedermayer <michael at niedermayer.cc> wrote:
>
>> On Thu, Sep 29, 2016 at 08:25:18PM +0200, wm4 wrote:
>> > This is a bit messy, mainly due to timestamp handling.
>> > 
>> > decode_video() relied on the fact that it could set dts on a flush/drain
>> > packet. This is not possible with the old API, and won't be. (I think
>> > doing this was very questionable with the old API. Flush packets should
>> > not contain any information; they just cause a FIFO to be emptied.) This
>> > is replaced with checking the best_effort_timestamp for AV_NOPTS_VALUE,
>> > and using the suggested DTS in the drain case.
>> > 
>> > The fate-cavs test still fails due to dropping the last frame. This
>> > happens because the timestamp of the last frame goes backwards
>> > (ffprobe -show_frames shows the same thing). I suspect that this
>> > "worked" due to the best effort timestamp logic picking the DTS
>> > over the decreasing PTS. Since this logic is in libavcodec (where
>> > it probably shouldn't be), this can't be easily fixed. The timestamps
>> > of the cavs samples are weird anyway, so I chose not to fix it.
>> > 
>> > Another strange thing is the timestamp handling in the video path of
>> > process_input_packet (after the decode_video() call). It looks like
>> > the code to increase next_dts and next_pts should be run every time
>> > a frame is decoded - but it's needed even if output is skipped.
>> > ---
>> >  ffmpeg.c            | 178 +++++++++++++++++++++++++++++++++++++---------------
>> >  ffmpeg.h            |   3 +
>> >  tests/ref/fate/cavs |   1 -
>> >  3 files changed, 129 insertions(+), 53 deletions(-) 
>> 
>> with this and patch 1/3
>> the following infinite loops
>> ./ffmpeg  -f openal -i ''  -t 0.1 file.wav
>
> Not a reasonably to reproduce test case as it requires installing
> OpenAL and possibly has specific hardware requirements.
>
> Will push this patch in 24 hours unless other problems are pointed out.

This seems like a very simple to fix bug in openal.

I will send a patch series soon.

Regards,
Marton