[FFmpeg-devel] [PATCH] libavformat/mxfdec.c refactor resolving MultiDescriptor and remove essence group hack

[Tomas Härdin]

On Tue, 2014-12-02 at 16:43 -0800, Mark Reid wrote:
> I think this is a better way to deal with single frame essence data then my
> previous way.
> 
> ---
>  libavformat/mxfdec.c | 62 ++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 38 insertions(+), 24 deletions(-)
> 
> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
> index 0c88a8a..6c104b9 100644
> --- a/libavformat/mxfdec.c
> +++ b/libavformat/mxfdec.c
> @@ -1508,6 +1508,32 @@ static MXFPackage* mxf_resolve_source_package(MXFContext *mxf, UID package_uid)
>      return NULL;
>  }
>  
> +static MXFDescriptor* mxf_resolve_multidescriptor(MXFContext *mxf, MXFDescriptor *descriptor, int track_id)
> +{
> +    MXFDescriptor *sub_descriptor = NULL;
> +    int i;
> +
> +    if (!descriptor)
> +        return NULL;
> +
> +    if (descriptor->type == MultipleDescriptor) {
> +        for (i = 0; i < descriptor->sub_descriptors_count; i++) {
> +            sub_descriptor = mxf_resolve_strong_ref(mxf, &descriptor->sub_descriptors_refs[i], Descriptor);
> +
> +            if (!sub_descriptor) {
> +                av_log(mxf->fc, AV_LOG_ERROR, "could not resolve sub descriptor strong ref\n");
> +                continue;
> +            }
> +            if (sub_descriptor->linked_track_id == track_id) {
> +                return sub_descriptor;
> +            }
> +        }
> +    } else if (descriptor->type == Descriptor)
> +        return descriptor;
> +
> +    return NULL;
> +}
> +
>  static MXFStructuralComponent* mxf_resolve_essence_group_choice(MXFContext *mxf, MXFEssenceGroup *essence_group)
>  {
>      MXFStructuralComponent *component = NULL;
> @@ -1529,12 +1555,8 @@ static MXFStructuralComponent* mxf_resolve_essence_group_choice(MXFContext *mxf,
>              continue;
>  
>          descriptor = mxf_resolve_strong_ref(mxf, &package->descriptor_ref, Descriptor);
> -        if (descriptor){
> -            /* HACK: force the duration of the component to match the duration of the descriptor */
> -            if (descriptor->duration != AV_NOPTS_VALUE)
> -                component->duration = descriptor->duration;
> +        if (descriptor)
>              return component;
> -        }
>      }
>      return NULL;
>  }
> @@ -1735,7 +1757,17 @@ static int mxf_parse_structural_metadata(MXFContext *mxf)
>          }
>          st->id = source_track->track_id;
>          st->priv_data = source_track;
> -        source_track->original_duration = st->duration = component->duration;
> +
> +        source_package->descriptor = mxf_resolve_strong_ref(mxf, &source_package->descriptor_ref, AnyType);
> +        descriptor = mxf_resolve_multidescriptor(mxf, source_package->descriptor, source_track->track_id);
> +
> +        /* A SourceClip from a EssenceGroup may only be a single frame of essence data. The clips duration is then how many
> +         * frames its suppose to repeat for. Descriptor->duration, if present, contains the real duration of the essence data */
> +        if (descriptor && descriptor->duration != AV_NOPTS_VALUE)
> +            source_track->original_duration = st->duration = FFMIN(descriptor->duration, component->duration);
> +        else
> +            source_track->original_duration = st->duration = component->duration;
> +
>          if (st->duration == -1)
>              st->duration = AV_NOPTS_VALUE;
>          st->start_time = component->start_position;
> @@ -1758,24 +1790,6 @@ static int mxf_parse_structural_metadata(MXFContext *mxf)
>          codec_ul = mxf_get_codec_ul(ff_mxf_data_definition_uls, &source_track->sequence->data_definition_ul);
>          st->codec->codec_type = codec_ul->id;
>  
> -        source_package->descriptor = mxf_resolve_strong_ref(mxf, &source_package->descriptor_ref, AnyType);
> -        if (source_package->descriptor) {
> -            if (source_package->descriptor->type == MultipleDescriptor) {
> -                for (j = 0; j < source_package->descriptor->sub_descriptors_count; j++) {
> -                    MXFDescriptor *sub_descriptor = mxf_resolve_strong_ref(mxf, &source_package->descriptor->sub_descriptors_refs[j], Descriptor);
> -
> -                    if (!sub_descriptor) {
> -                        av_log(mxf->fc, AV_LOG_ERROR, "could not resolve sub descriptor strong ref\n");
> -                        continue;
> -                    }
> -                    if (sub_descriptor->linked_track_id == source_track->track_id) {
> -                        descriptor = sub_descriptor;
> -                        break;
> -                    }
> -                }
> -            } else if (source_package->descriptor->type == Descriptor)
> -                descriptor = source_package->descriptor;
> -        }
>          if (!descriptor) {
>              av_log(mxf->fc, AV_LOG_INFO, "source track %d: stream %d, no descriptor found\n", source_track->track_id, st->index);
>              continue;


Seems alright..

/Tomas
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