[FFmpeg-devel] [PATCH] fix stream copy

[Baptiste Coudurier]

On 01/27/2010 01:47 AM, Maksym Veremeyenko wrote:
> Baptiste Coudurier ???????(??):
> [...]
>> Yes, pkt->duration might not be set for some reasons.
>> Did you test this ?
> i missed that situation.
>
> If pkt->duration is 0 (unknown) i do not know how to handle this
> situation properly.
>
> So alternative patch "fix stream copy for most cases..." could looks like:
>
> Index: ffmpeg.c
> ===================================================================
> --- ffmpeg.c (revision 21473)
> +++ ffmpeg.c (working copy)
> @@ -1484,7 +1484,10 @@
> audio_size += data_size;
> else if (ost->st->codec->codec_type == CODEC_TYPE_VIDEO) {
> video_size += data_size;
> - ost->sync_opts++;
> + if(pkt->duration)
> + ost->sync_opts += av_rescale_q(pkt->duration, ist->st->time_base,
> ost->st->codec->time_base);
> + else
> + ost->sync_opts++;
> }
>
> opkt.stream_index= ost->index;
>

Well the problem is the definition of sync_opts:
     int64_t sync_opts;       /* output frame counter, could be changed 
to some true timestamp */ //FIXME look at frame_number

With your patch the definition would become wrong in some cases.

>>
>> One other possible solution is to use pts.val when stream copy is used.
>>
> it will require changing another part of code where ost->sync_opts used
> for stop condition or keep previous packet pts to calc duration of
> previous packet....
>

Hummm, I'm not sure what you mean, but this seems to fix the issue for 
me. Can you confirm ?

The idea is to only use sync_opts if the codec time base of the output 
looks like a frame rate.

Michael what do you think ? I'm not sure why video is treated separately.

-- 
Baptiste COUDURIER
Key fingerprint                 8D77134D20CC9220201FC5DB0AC9325C5C1ABAAA
FFmpeg maintainer                                  http://www.ffmpeg.org
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