[FFmpeg-devel] [PATCHv2 3/5] avformat/mxfdec: guess wrapping of tracks by other tracks with the same body sid

Marton Balint cus at passwd.hu
Wed Apr 24 23:31:15 EEST 2019



On Wed, 24 Apr 2019, Tomas Härdin wrote:

> mån 2019-04-22 klockan 19:15 +0200 skrev Marton Balint:
>> This affects the following samples:
>> 
>> samples/ffmpeg-bugs/roundup/issue1775/av_seek_frame_failure.mxf
>> samples/ffmpeg-bugs/trac/ticket1957/16ch.mxf
>> samples/ffmpeg-bugs/trac/ticket5016/r0.mxf
>> samples/ffmpeg-bugs/trac/ticket5016/r1.mxf
>> samples/ffmpeg-bugs/trac/ticket5316/hq.MXF
>> samples/ffmpeg-bugs/trac/ticket5316/hqx.MXF
>> 
>> Some AVPacket->pos values are changed because for frame wrapped tracks we point
>> to the KLV offset and not the data.
>> 
>> > Signed-off-by: Marton Balint <cus at passwd.hu>
>> ---
>>  libavformat/mxfdec.c | 18 ++++++++++++++++++
>>  1 file changed, 18 insertions(+)
>> 
>> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
>> index 2c44852062..034025bcaa 100644
>> --- a/libavformat/mxfdec.c
>> +++ b/libavformat/mxfdec.c
>> @@ -2553,6 +2553,24 @@ static int mxf_parse_structural_metadata(MXFContext *mxf)
>>          }
>>      }
>>  
>> +    for (int i = 0; i < mxf->fc->nb_streams; i++) {
>> +        MXFTrack *track1 = mxf->fc->streams[i]->priv_data;
>> +        if (track1 && track1->body_sid) {
>> +            for (int j = i + 1; j < mxf->fc->nb_streams; j++) {
>> +                MXFTrack *track2 = mxf->fc->streams[j]->priv_data;
>> +                if (track2 && track1->body_sid == track2->body_sid && track1->wrapping != track2->wrapping) {
>> +                    if (track1->wrapping == UnknownWrapped)
>> +                        track1->wrapping = track2->wrapping;
>> +                    else if (track2->wrapping == UnknownWrapped)
>> +                        track2->wrapping = track1->wrapping;
>> +                    else
>> +                        av_log(mxf->fc, AV_LOG_ERROR, "stream %d and stream %d have the same BodySID (%d) "
>> +                                                      "with different wrapping\n", i, j, track1->body_sid);
>> +                }
>> +            }
>> +        }
>> +    }
>
> Don't we have mxf_get_wrapping_by_body_sid() for this?
>

That is similar, yes, but in order to find and warn about every mismatch 
between frame wrapped and clip wrapped as you suggested we cannot use it 
here directly (mxf_get_wrapping_by_body_sid finds the first stream with a 
known wrapping and a matching body sid).

Also we cannot warn in mxf_get_wrapping_by_body_sid because that is called 
for each partition.

Regards,
Marton


More information about the ffmpeg-devel mailing list