mxf.c

ffmpeg的完整源代码和作者自己写的文档。不但有在Linux的工程哦

            (type == AnyType || mxf->metadata_sets[i]->type == type)) {
            return mxf->metadata_sets[i];
        }
    }
    return NULL;
}

static int mxf_parse_structural_metadata(MXFContext *mxf)
{
    MXFPackage *material_package = NULL;
    MXFPackage *temp_package = NULL;
    int i, j, k;

    dprintf(mxf->fc, "metadata sets count %d\n", mxf->metadata_sets_count);
    /* TODO: handle multiple material packages (OP3x) */
    for (i = 0; i < mxf->packages_count; i++) {
        material_package = mxf_resolve_strong_ref(mxf, &mxf->packages_refs[i], MaterialPackage);
        if (material_package) break;
    }
    if (!material_package) {
        av_log(mxf->fc, AV_LOG_ERROR, "no material package found\n");
        return -1;
    }

    for (i = 0; i < material_package->tracks_count; i++) {
        MXFPackage *source_package = NULL;
        MXFTrack *material_track = NULL;
        MXFTrack *source_track = NULL;
        MXFTrack *temp_track = NULL;
        MXFDescriptor *descriptor = NULL;
        MXFStructuralComponent *component = NULL;
        UID *essence_container_ul = NULL;
        const MXFCodecUL *codec_ul = NULL;
        const MXFCodecUL *container_ul = NULL;
        AVStream *st;

        if (!(material_track = mxf_resolve_strong_ref(mxf, &material_package->tracks_refs[i], Track))) {
            av_log(mxf->fc, AV_LOG_ERROR, "could not resolve material track strong ref\n");
            continue;
        }

        if (!(material_track->sequence = mxf_resolve_strong_ref(mxf, &material_track->sequence_ref, Sequence))) {
            av_log(mxf->fc, AV_LOG_ERROR, "could not resolve material track sequence strong ref\n");
            return -1;
        }

        /* TODO: handle multiple source clips */
        for (j = 0; j < material_track->sequence->structural_components_count; j++) {
            /* TODO: handle timecode component */
            component = mxf_resolve_strong_ref(mxf, &material_track->sequence->structural_components_refs[j], SourceClip);
            if (!component)
                continue;

            for (k = 0; k < mxf->packages_count; k++) {
                temp_package = mxf_resolve_strong_ref(mxf, &mxf->packages_refs[k], SourcePackage);
                if (!temp_package)
                    continue;
                if (!memcmp(temp_package->package_uid, component->source_package_uid, 16)) {
                    source_package = temp_package;
                    break;
                }
            }
            if (!source_package) {
                av_log(mxf->fc, AV_LOG_ERROR, "material track %d: no corresponding source package found\n", material_track->track_id);
                break;
            }
            for (k = 0; k < source_package->tracks_count; k++) {
                if (!(temp_track = mxf_resolve_strong_ref(mxf, &source_package->tracks_refs[k], Track))) {
                    av_log(mxf->fc, AV_LOG_ERROR, "could not resolve source track strong ref\n");
                    return -1;
                }
                if (temp_track->track_id == component->source_track_id) {
                    source_track = temp_track;
                    break;
                }
            }
            if (!source_track) {
                av_log(mxf->fc, AV_LOG_ERROR, "material track %d: no corresponding source track found\n", material_track->track_id);
                break;
            }
        }
        if (!source_track)
            continue;

        st = av_new_stream(mxf->fc, source_track->track_id);
        st->priv_data = source_track;
        st->duration = component->duration;
        if (st->duration == -1)
            st->duration = AV_NOPTS_VALUE;
        st->start_time = component->start_position;
        av_set_pts_info(st, 64, material_track->edit_rate.num, material_track->edit_rate.den);

        if (!(source_track->sequence = mxf_resolve_strong_ref(mxf, &source_track->sequence_ref, Sequence))) {
            av_log(mxf->fc, AV_LOG_ERROR, "could not resolve source track sequence strong ref\n");
            return -1;
        }

#ifdef DEBUG
        PRINT_KEY(mxf->fc, "data definition   ul", source_track->sequence->data_definition_ul);
#endif
        st->codec->codec_type = mxf_get_codec_type(mxf_data_definition_uls, &source_track->sequence->data_definition_ul);

        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;
        }
#ifdef DEBUG
        PRINT_KEY(mxf->fc, "essence codec     ul", descriptor->essence_codec_ul);
        PRINT_KEY(mxf->fc, "essence container ul", descriptor->essence_container_ul);
#endif
        essence_container_ul = &descriptor->essence_container_ul;
        /* HACK: replacing the original key with mxf_encrypted_essence_container
         * is not allowed according to s429-6, try to find correct information anyway */
        if (IS_KLV_KEY(essence_container_ul, mxf_encrypted_essence_container)) {
            av_log(mxf->fc, AV_LOG_INFO, "broken encrypted mxf file\n");
            for (k = 0; k < mxf->metadata_sets_count; k++) {
                MXFMetadataSet *metadata = mxf->metadata_sets[k];
                if (metadata->type == CryptoContext) {
                    essence_container_ul = &((MXFCryptoContext *)metadata)->source_container_ul;
                    break;
                }
            }
        }
        /* TODO: drop PictureEssenceCoding and SoundEssenceCompression, only check EssenceContainer */
        codec_ul = mxf_get_codec_ul(mxf_codec_uls, &descriptor->essence_codec_ul);
        st->codec->codec_id = codec_ul->id;
        if (descriptor->extradata) {
            st->codec->extradata = descriptor->extradata;
            st->codec->extradata_size = descriptor->extradata_size;
        }
        if (st->codec->codec_type == CODEC_TYPE_VIDEO) {
            container_ul = mxf_get_codec_ul(mxf_picture_essence_container_uls, essence_container_ul);
            if (st->codec->codec_id == CODEC_ID_NONE)
                st->codec->codec_id = container_ul->id;
            st->codec->width = descriptor->width;
            st->codec->height = descriptor->height;
            st->codec->bits_per_sample = descriptor->bits_per_sample; /* Uncompressed */
            st->need_parsing = AVSTREAM_PARSE_HEADERS;
        } else if (st->codec->codec_type == CODEC_TYPE_AUDIO) {
            container_ul = mxf_get_codec_ul(mxf_sound_essence_container_uls, essence_container_ul);
            if (st->codec->codec_id == CODEC_ID_NONE)
                st->codec->codec_id = container_ul->id;
            st->codec->channels = descriptor->channels;
            st->codec->bits_per_sample = descriptor->bits_per_sample;
            st->codec->sample_rate = descriptor->sample_rate.num / descriptor->sample_rate.den;
            /* TODO: implement CODEC_ID_RAWAUDIO */
            if (st->codec->codec_id == CODEC_ID_PCM_S16LE) {
                if (descriptor->bits_per_sample == 24)
                    st->codec->codec_id = CODEC_ID_PCM_S24LE;
                else if (descriptor->bits_per_sample == 32)
                    st->codec->codec_id = CODEC_ID_PCM_S32LE;
            } else if (st->codec->codec_id == CODEC_ID_PCM_S16BE) {
                if (descriptor->bits_per_sample == 24)
                    st->codec->codec_id = CODEC_ID_PCM_S24BE;
                else if (descriptor->bits_per_sample == 32)
                    st->codec->codec_id = CODEC_ID_PCM_S32BE;
            } else if (st->codec->codec_id == CODEC_ID_MP2) {
                st->need_parsing = AVSTREAM_PARSE_FULL;
            }
        }
        if (container_ul && container_ul->wrapping == Clip) {
            dprintf(mxf->fc, "stream %d: clip wrapped essence\n", st->index);
            st->need_parsing = AVSTREAM_PARSE_FULL;
        }
    }
    return 0;
}

static const MXFMetadataReadTableEntry mxf_metadata_read_table[] = {
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x18,0x00 }, mxf_read_metadata_content_storage, 0, AnyType },
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x37,0x00 }, mxf_read_metadata_source_package, sizeof(MXFPackage), SourcePackage },
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x36,0x00 }, mxf_read_metadata_material_package, sizeof(MXFPackage), MaterialPackage },
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x0F,0x00 }, mxf_read_metadata_sequence, sizeof(MXFSequence), Sequence },
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x11,0x00 }, mxf_read_metadata_source_clip, sizeof(MXFStructuralComponent), SourceClip },
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x44,0x00 }, mxf_read_metadata_generic_descriptor, sizeof(MXFDescriptor), MultipleDescriptor },
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x42,0x00 }, mxf_read_metadata_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* Generic Sound */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x28,0x00 }, mxf_read_metadata_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* CDCI */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x29,0x00 }, mxf_read_metadata_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* RGBA */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x51,0x00 }, mxf_read_metadata_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* MPEG 2 Video */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x48,0x00 }, mxf_read_metadata_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* Wave */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x47,0x00 }, mxf_read_metadata_generic_descriptor, sizeof(MXFDescriptor), Descriptor }, /* AES3 */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x3A,0x00 }, mxf_read_metadata_track, sizeof(MXFTrack), Track }, /* Static Track */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x01,0x01,0x01,0x01,0x3B,0x00 }, mxf_read_metadata_track, sizeof(MXFTrack), Track }, /* Generic Track */
    { { 0x06,0x0E,0x2B,0x34,0x02,0x53,0x01,0x01,0x0d,0x01,0x04,0x01,0x02,0x02,0x00,0x00 }, mxf_read_metadata_cryptographic_context, sizeof(MXFCryptoContext), CryptoContext },
    { { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 }, NULL, 0, AnyType },
};

static int mxf_read_local_tags(MXFContext *mxf, KLVPacket *klv, int (*read_child)(), int ctx_size, enum MXFMetadataSetType type)
{
    ByteIOContext *pb = &mxf->fc->pb;
    MXFMetadataSet *ctx = ctx_size ? av_mallocz(ctx_size) : mxf;
    uint64_t klv_end= url_ftell(pb) + klv->length;

    while (url_ftell(pb) + 4 < klv_end) {
        int tag = get_be16(pb);
        int size = get_be16(pb); /* KLV specified by 0x53 */
        uint64_t next= url_ftell(pb) + size;

        if (!size) { /* ignore empty tag, needed for some files with empty UMID tag */
            av_log(mxf->fc, AV_LOG_ERROR, "local tag 0x%04X with 0 size\n", tag);
            continue;
        }
        if(ctx_size && tag == 0x3C0A)
            get_buffer(pb, ctx->uid, 16);
        else
            read_child(ctx, pb, tag, size);

        url_fseek(pb, next, SEEK_SET);
    }
    if (ctx_size) ctx->type = type;
    return ctx_size ? mxf_add_metadata_set(mxf, ctx) : 0;
}

static int mxf_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    MXFContext *mxf = s->priv_data;
    KLVPacket klv;

    if (!mxf_read_sync(&s->pb, mxf_header_partition_pack_key, 14)) {
        av_log(s, AV_LOG_ERROR, "could not find header partition pack key\n");
        return -1;
    }
    url_fseek(&s->pb, -14, SEEK_CUR);
    mxf->fc = s;
    while (!url_feof(&s->pb)) {
        const MXFMetadataReadTableEntry *metadata;

        if (klv_read_packet(&klv, &s->pb) < 0)
            return -1;
#ifdef DEBUG
        PRINT_KEY(s, "read header", klv.key);
#endif
        if (IS_KLV_KEY(klv.key, mxf_encrypted_triplet_key) ||
            IS_KLV_KEY(klv.key, mxf_essence_element_key)) {
            /* FIXME avoid seek */
            url_fseek(&s->pb, klv.offset, SEEK_SET);
            break;
        }

        for (metadata = mxf_metadata_read_table; metadata->read; metadata++) {
            if (IS_KLV_KEY(klv.key, metadata->key)) {
                if (mxf_read_local_tags(mxf, &klv, metadata->read, metadata->ctx_size, metadata->type) < 0) {
                    av_log(s, AV_LOG_ERROR, "error reading header metadata\n");
                    return -1;
                }
                break;
            }
        }
        if (!metadata->read)
            url_fskip(&s->pb, klv.length);
    }
    return mxf_parse_structural_metadata(mxf);
}

static int mxf_read_close(AVFormatContext *s)
{
    MXFContext *mxf = s->priv_data;
    int i;

    av_freep(&mxf->packages_refs);
    for (i = 0; i < mxf->metadata_sets_count; i++) {
        switch (mxf->metadata_sets[i]->type) {
        case MultipleDescriptor:
            av_freep(&((MXFDescriptor *)mxf->metadata_sets[i])->sub_descriptors_refs);
            break;
        case Sequence:
            av_freep(&((MXFSequence *)mxf->metadata_sets[i])->structural_components_refs);
            break;
        case SourcePackage:
        case MaterialPackage:
            av_freep(&((MXFPackage *)mxf->metadata_sets[i])->tracks_refs);
            break;
        default:
            break;
        }
        av_freep(&mxf->metadata_sets[i]);
    }
    av_freep(&mxf->metadata_sets);
    av_freep(&mxf->aesc);
    return 0;
}

static int mxf_probe(AVProbeData *p) {
    uint8_t *bufp = p->buf;
    uint8_t *end = p->buf + p->buf_size;

    if (p->buf_size < sizeof(mxf_header_partition_pack_key))
        return 0;

    /* Must skip Run-In Sequence and search for MXF header partition pack key SMPTE 377M 5.5 */
    end -= sizeof(mxf_header_partition_pack_key);
    for (; bufp < end; bufp++) {
        if (IS_KLV_KEY(bufp, mxf_header_partition_pack_key))
            return AVPROBE_SCORE_MAX;
    }
    return 0;
}

/* rudimentary byte seek */
/* XXX: use MXF Index */
static int mxf_read_seek(AVFormatContext *s, int stream_index, int64_t sample_time, int flags)
{
    AVStream *st = s->streams[stream_index];
    int64_t seconds;

    if (!s->bit_rate)
        return -1;
    if (sample_time < 0)
        sample_time = 0;
    seconds = av_rescale(sample_time, st->time_base.num, st->time_base.den);
    url_fseek(&s->pb, (s->bit_rate * seconds) >> 3, SEEK_SET);
    av_update_cur_dts(s, st, sample_time);
    return 0;
}

AVInputFormat mxf_demuxer = {
    "mxf",
    "MXF format",
    sizeof(MXFContext),
    mxf_probe,
    mxf_read_header,
    mxf_read_packet,
    mxf_read_close,
    mxf_read_seek,
};