[vlc-devel] [PATCH] transcoding: avoid a divide by 0 when source video framerate is mistakenly set to 0 by a demuxer

[Emeric Grange]

2015-10-07 11:18 GMT+02:00 Emeric Grange <emeric.grange at gmail.com>:
> 2015-10-06 19:10 GMT+02:00 Ilkka Ollakka <ileoo at videolan.org>:
>>
>> On Tue, Oct 06, 2015 at 02:57:03PM +0200, Emeric Grange wrote:
>>
>> Hi,
>>
>> Patch looks ok, but I have feeling that most cases default framerate is wrong on cases where
>> demuxer isn't able to give. Do you have some cases currently that
>> demuxer fails to get framerate but that default is actually reasonable
>> guess?
>>
>> > ---
>> >  modules/stream_out/transcode/video.c | 10 +++++++++-
>> >  1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> > diff --git a/modules/stream_out/transcode/video.c b/modules/stream_out/transcode/video.c
>> > index 2c2d4f3..8f85036 100644
>> > --- a/modules/stream_out/transcode/video.c
>> > +++ b/modules/stream_out/transcode/video.c
>> > @@ -465,7 +465,7 @@ static void transcode_video_encoder_init( sout_stream_t *p_stream,
>> >           i_dst_visible_width, i_dst_visible_height
>> >       );
>>
>> > -    /* Handle frame rate conversion */
>> > +    /* Handle frame rate conversion (encoder) */
>> >      if( !id->p_encoder->fmt_out.video.i_frame_rate ||
>> >          !id->p_encoder->fmt_out.video.i_frame_rate_base )
>> >      {
>> > @@ -485,6 +485,14 @@ static void transcode_video_encoder_init( sout_stream_t *p_stream,
>> >          }
>> >      }
>>
>> > +    /* Handle frame rate (decoder) */
>> > +    if (!id->p_decoder->fmt_out.video.i_frame_rate ||
>> > +        !id->p_decoder->fmt_out.video.i_frame_rate_base)
>> > +    {
>> > +        id->p_decoder->fmt_out.video.i_frame_rate = ENC_FRAMERATE;
>> > +        id->p_decoder->fmt_out.video.i_frame_rate_base = ENC_FRAMERATE_BASE;
>> > +    }
>> > +
>> >      id->p_encoder->fmt_in.video.orientation =
>> >          id->p_encoder->fmt_out.video.orientation =
>> >          id->p_decoder->fmt_in.video.orientation;
>> --
>> Ilkka Ollakka
>> Each person has the right to take the subway.
>>
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>
> Hi,
> Yes you are right the default will probably be wrong, the goal was
> only to avoid VLC segfaulting. My use case was trancoding mp4 file
> with "DASH style" tracks from youtube, and the problem was not an
> exotic framerate but just the mp4 parser unable to get framerate. Most
> files are 24fps so 25 is not that far of.
> Maybe the proper way to handle that situation is just to fail with an
> error trace then.
>
> Emeric

Anything new about this patch?

Emeric