[FFmpeg-devel] [PATCH v2 1/3] avformat/mxfenc: use track count to generate component instance uuid

[Mark Reid]

On Wed, Nov 29, 2017 at 1:36 AM, Tomas Härdin <tjoppen at acc.umu.se> wrote:

> On 2017-11-29 05:11, Mark Reid wrote:
>
>> @@ -980,7 +980,7 @@ static void mxf_write_structural_component(AVFormatContext
>> *s, AVStream *st, MXF
>>         // write uid
>>       mxf_write_local_tag(pb, 16, 0x3C0A);
>> -    mxf_write_uuid(pb, package->type == MaterialPackage ? SourceClip:
>> SourceClip + TypeBottom, st->index);
>> +    mxf_write_uuid(pb, SourceClip, mxf->track_uuid_offset);
>>         PRINT_KEY(s, "structural component uid", pb->buf_ptr - 16);
>>       mxf_write_common_fields(s, st);
>> @@ -1357,7 +1357,7 @@ static void mxf_write_package(AVFormatContext *s,
>> MXFPackage *package)
>>         // write package umid
>>       mxf_write_local_tag(pb, 32, 0x4401);
>> -    mxf_write_umid(s, package->type == SourcePackage);
>> +    mxf_write_umid(s, package->instance);
>>       PRINT_KEY(s, "package umid second part", pb->buf_ptr - 16);
>>         // package name
>> @@ -1375,10 +1375,9 @@ static void mxf_write_package(AVFormatContext *s,
>> MXFPackage *package)
>>       // write track refs
>>       mxf_write_local_tag(pb, track_count*16 + 8, 0x4403);
>>       mxf_write_refs_count(pb, track_count);
>> -    mxf_write_uuid(pb, package->type == MaterialPackage ? Track :
>> -                   Track + TypeBottom, -1); // timecode track
>> +    mxf_write_uuid(pb, Track, mxf->track_uuid_offset); // timecode track
>>       for (i = 0; i < s->nb_streams; i++)
>> -        mxf_write_uuid(pb, package->type == MaterialPackage ? Track :
>> Track + TypeBottom, i);
>> +        mxf_write_uuid(pb, Track,  mxf->track_uuid_offset + i + 1);
>>
>
> Do these refer to tracks that are about to be written? Seems so as best I
> can tell, so I guess it works. I'd be happier if the referencing was done
> more explicitly rather than implicitly


yes they refer to the tracks about to be written. Those uuids need to match
the uuid instance tag (0x3C0A) on a track written in mxf_write_track. then
the uuid ref on the track needs to match the one on the sequence, and then
the one the sequence needs to match the one on the component.

would you rather the instance id be a argument to each of the write
functions? for example:
mxf_write_package(AVFormatContext *s, MXFPackage *package, int
track_uuid_offset)
mxf_write_track(AVFormatContext *s, AVStream *st, MXFPackage *package, int
instance_id)
would that be more explicit?



>
>         // write user comment refs
>>       if (mxf->store_user_comments) {
>> @@ -1402,12 +1401,14 @@ static void mxf_write_package(AVFormatContext
>> *s, MXFPackage *package)
>>       mxf_write_track(s, mxf->timecode_track, package);
>>       mxf_write_sequence(s, mxf->timecode_track, package);
>>       mxf_write_timecode_component(s, mxf->timecode_track, package);
>> +    mxf->track_uuid_offset++;
>>         for (i = 0; i < s->nb_streams; i++) {
>>           AVStream *st = s->streams[i];
>>           mxf_write_track(s, st, package);
>>           mxf_write_sequence(s, st, package);
>>           mxf_write_structural_component(s, st, package);
>> +        mxf->track_uuid_offset++;
>>
>>
>
> /Tomas
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