mov.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

{ MKTAG( 'j', 'p', '2', 'h' ), mov_read_extradata },
{ MKTAG( 'm', 'd', 'a', 't' ), mov_read_mdat },
{ MKTAG( 'm', 'd', 'h', 'd' ), mov_read_mdhd },
{ MKTAG( 'm', 'd', 'i', 'a' ), mov_read_default },
{ MKTAG( 'm', 'i', 'n', 'f' ), mov_read_default },
{ MKTAG( 'm', 'o', 'o', 'v' ), mov_read_moov },
{ MKTAG( 'm', 'v', 'h', 'd' ), mov_read_mvhd },
{ MKTAG( 'S', 'M', 'I', ' ' ), mov_read_smi }, /* Sorenson extension ??? */
{ MKTAG( 'a', 'l', 'a', 'c' ), mov_read_extradata }, /* alac specific atom */
{ MKTAG( 'a', 'v', 'c', 'C' ), mov_read_avcC },
{ MKTAG( 's', 't', 'b', 'l' ), mov_read_default },
{ MKTAG( 's', 't', 'c', 'o' ), mov_read_stco },
{ MKTAG( 's', 't', 's', 'c' ), mov_read_stsc },
{ MKTAG( 's', 't', 's', 'd' ), mov_read_stsd }, /* sample description */
{ MKTAG( 's', 't', 's', 's' ), mov_read_stss }, /* sync sample */
{ MKTAG( 's', 't', 's', 'z' ), mov_read_stsz }, /* sample size */
{ MKTAG( 's', 't', 't', 's' ), mov_read_stts },
{ MKTAG( 't', 'k', 'h', 'd' ), mov_read_tkhd }, /* track header */
{ MKTAG( 't', 'r', 'a', 'k' ), mov_read_trak },
{ MKTAG( 'u', 'd', 't', 'a' ), mov_read_udta },
{ MKTAG( 'w', 'a', 'v', 'e' ), mov_read_wave },
{ MKTAG( 'e', 's', 'd', 's' ), mov_read_esds },
{ MKTAG( 'w', 'i', 'd', 'e' ), mov_read_wide }, /* place holder */
{ MKTAG( 'c', 'm', 'o', 'v' ), mov_read_cmov },
{ 0L, NULL }
};

/* XXX: is it sufficient ? */
static int mov_probe(AVProbeData *p)
{
    unsigned int offset;
    uint32_t tag;
    int score = 0;

    /* check file header */
    offset = 0;
    for(;;) {
        /* ignore invalid offset */
        if ((offset + 8) > (unsigned int)p->buf_size)
            return score;
        tag = AV_RL32(p->buf + offset + 4);
        switch(tag) {
        /* check for obvious tags */
        case MKTAG( 'j', 'P', ' ', ' ' ): /* jpeg 2000 signature */
        case MKTAG( 'm', 'o', 'o', 'v' ):
        case MKTAG( 'm', 'd', 'a', 't' ):
        case MKTAG( 'p', 'n', 'o', 't' ): /* detect movs with preview pics like ew.mov and april.mov */
        case MKTAG( 'u', 'd', 't', 'a' ): /* Packet Video PVAuthor adds this and a lot of more junk */
            return AVPROBE_SCORE_MAX;
        /* those are more common words, so rate then a bit less */
        case MKTAG( 'e', 'd', 'i', 'w' ): /* xdcam files have reverted first tags */
        case MKTAG( 'w', 'i', 'd', 'e' ):
        case MKTAG( 'f', 'r', 'e', 'e' ):
        case MKTAG( 'j', 'u', 'n', 'k' ):
        case MKTAG( 'p', 'i', 'c', 't' ):
            return AVPROBE_SCORE_MAX - 5;
        case MKTAG( 'f', 't', 'y', 'p' ):
        case MKTAG( 's', 'k', 'i', 'p' ):
        case MKTAG( 'u', 'u', 'i', 'd' ):
            offset = AV_RB32(p->buf+offset) + offset;
            /* if we only find those cause probedata is too small at least rate them */
            score = AVPROBE_SCORE_MAX - 50;
            break;
        default:
            /* unrecognized tag */
            return score;
        }
    }
    return score;
}

static void mov_build_index(MOVContext *mov, AVStream *st)
{
    MOVStreamContext *sc = st->priv_data;
    offset_t current_offset;
    int64_t current_dts = 0;
    unsigned int stts_index = 0;
    unsigned int stsc_index = 0;
    unsigned int stss_index = 0;
    unsigned int i, j, k;

    if (sc->sample_sizes || st->codec->codec_type == CODEC_TYPE_VIDEO || sc->dv_audio_container) {
        unsigned int current_sample = 0;
        unsigned int stts_sample = 0;
        unsigned int keyframe, sample_size;
        unsigned int distance = 0;

        st->nb_frames = sc->sample_count;
        for (i = 0; i < sc->chunk_count; i++) {
            current_offset = sc->chunk_offsets[i];
            if (stsc_index + 1 < sc->sample_to_chunk_sz && i + 1 == sc->sample_to_chunk[stsc_index + 1].first)
                stsc_index++;
            for (j = 0; j < sc->sample_to_chunk[stsc_index].count; j++) {
                if (current_sample >= sc->sample_count) {
                    av_log(mov->fc, AV_LOG_ERROR, "wrong sample count\n");
                    goto out;
                }
                keyframe = !sc->keyframe_count || current_sample + 1 == sc->keyframes[stss_index];
                if (keyframe) {
                    distance = 0;
                    if (stss_index + 1 < sc->keyframe_count)
                        stss_index++;
                }
                sample_size = sc->sample_size > 0 ? sc->sample_size : sc->sample_sizes[current_sample];
                dprintf(mov->fc, "AVIndex stream %d, sample %d, offset %"PRIx64", dts %"PRId64", size %d, distance %d, keyframe %d\n",
                        st->index, current_sample, current_offset, current_dts, sample_size, distance, keyframe);
                av_add_index_entry(st, current_offset, current_dts, sample_size, distance, keyframe ? AVINDEX_KEYFRAME : 0);
                current_offset += sample_size;
                assert(sc->stts_data[stts_index].duration % sc->time_rate == 0);
                current_dts += sc->stts_data[stts_index].duration / sc->time_rate;
                distance++;
                stts_sample++;
                current_sample++;
                if (stts_index + 1 < sc->stts_count && stts_sample == sc->stts_data[stts_index].count) {
                    stts_sample = 0;
                    stts_index++;
                }
            }
        }
    } else { /* read whole chunk */
        unsigned int chunk_samples, chunk_size, chunk_duration;

        for (i = 0; i < sc->chunk_count; i++) {
            current_offset = sc->chunk_offsets[i];
            if (stsc_index + 1 < sc->sample_to_chunk_sz && i + 1 == sc->sample_to_chunk[stsc_index + 1].first)
                stsc_index++;
            chunk_samples = sc->sample_to_chunk[stsc_index].count;
            /* get chunk size */
            if (sc->sample_size > 1 || st->codec->codec_id == CODEC_ID_PCM_U8 || st->codec->codec_id == CODEC_ID_PCM_S8)
                chunk_size = chunk_samples * sc->sample_size;
            else if (sc->samples_per_frame > 0 && (chunk_samples * sc->bytes_per_frame % sc->samples_per_frame == 0))
                chunk_size = chunk_samples * sc->bytes_per_frame / sc->samples_per_frame;
            else { /* workaround to find nearest next chunk offset */
                chunk_size = INT_MAX;
                for (j = 0; j < mov->total_streams; j++) {
                    MOVStreamContext *msc = mov->streams[j];

                    for (k = msc->next_chunk; k < msc->chunk_count; k++) {
                        if (msc->chunk_offsets[k] > current_offset && msc->chunk_offsets[k] - current_offset < chunk_size) {
                            chunk_size = msc->chunk_offsets[k] - current_offset;
                            msc->next_chunk = k;
                            break;
                        }
                    }
                }
                /* check for last chunk */
                if (chunk_size == INT_MAX)
                    for (j = 0; j < mov->mdat_count; j++) {
                        dprintf(mov->fc, "mdat %d, offset %"PRIx64", size %"PRId64", current offset %"PRIx64"\n",
                                j, mov->mdat_list[j].offset, mov->mdat_list[j].size, current_offset);
                        if (mov->mdat_list[j].offset <= current_offset && mov->mdat_list[j].offset + mov->mdat_list[j].size > current_offset)
                            chunk_size = mov->mdat_list[j].offset + mov->mdat_list[j].size - current_offset;
                    }
                assert(chunk_size != INT_MAX);
                for (j = 0; j < mov->total_streams; j++) {
                    mov->streams[j]->next_chunk = 0;
                }
            }
            av_add_index_entry(st, current_offset, current_dts, chunk_size, 0, AVINDEX_KEYFRAME);
            /* get chunk duration */
            chunk_duration = 0;
            while (chunk_samples > 0) {
                if (chunk_samples < sc->stts_data[stts_index].count) {
                    chunk_duration += sc->stts_data[stts_index].duration * chunk_samples;
                    sc->stts_data[stts_index].count -= chunk_samples;
                    break;
                } else {
                    chunk_duration += sc->stts_data[stts_index].duration * chunk_samples;
                    chunk_samples -= sc->stts_data[stts_index].count;
                    if (stts_index + 1 < sc->stts_count) {
                        stts_index++;
                    }
                }
            }
            dprintf(mov->fc, "AVIndex stream %d, chunk %d, offset %"PRIx64", dts %"PRId64", size %d, duration %d\n",
                    st->index, i, current_offset, current_dts, chunk_size, chunk_duration);
            assert(chunk_duration % sc->time_rate == 0);
            current_dts += chunk_duration / sc->time_rate;
        }
    }
 out:
    /* adjust sample count to avindex entries */
    sc->sample_count = st->nb_index_entries;
}

static int mov_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    MOVContext *mov = s->priv_data;
    ByteIOContext *pb = &s->pb;
    int i, err;
    MOV_atom_t atom = { 0, 0, 0 };

    mov->fc = s;
    mov->parse_table = mov_default_parse_table;

    if(!url_is_streamed(pb)) /* .mov and .mp4 aren't streamable anyway (only progressive download if moov is before mdat) */
        atom.size = url_fsize(pb);
    else
        atom.size = INT64_MAX;

    /* check MOV header */
    err = mov_read_default(mov, pb, atom);
    if (err<0 || (!mov->found_moov && !mov->found_mdat)) {
        av_log(s, AV_LOG_ERROR, "mov: header not found !!! (err:%d, moov:%d, mdat:%d) pos:%"PRId64"\n",
                err, mov->found_moov, mov->found_mdat, url_ftell(pb));
        return -1;
    }
    dprintf(mov->fc, "on_parse_exit_offset=%d\n", (int) url_ftell(pb));

    /* some cleanup : make sure we are on the mdat atom */
    if(!url_is_streamed(pb) && (url_ftell(pb) != mov->mdat_offset))
        url_fseek(pb, mov->mdat_offset, SEEK_SET);

    mov->total_streams = s->nb_streams;

    for(i=0; i<mov->total_streams; i++) {
        MOVStreamContext *sc = mov->streams[i];
        AVStream *st = s->streams[i];
        /* sanity checks */
        if(!sc->stts_count || !sc->chunk_count || !sc->sample_to_chunk_sz ||
           (!sc->sample_size && !sc->sample_count)){
            av_log(s, AV_LOG_ERROR, "missing mandatory atoms, broken header\n");
            sc->sample_count = 0; //ignore track
            continue;
        }
        if(!sc->time_rate)
            sc->time_rate=1;
        if(!sc->time_scale)
            sc->time_scale= mov->time_scale;
        av_set_pts_info(st, 64, sc->time_rate, sc->time_scale);

        if (st->codec->codec_type == CODEC_TYPE_AUDIO && sc->stts_count == 1)
            st->codec->frame_size = sc->stts_data[0].duration;

        if(st->duration != AV_NOPTS_VALUE){
            assert(st->duration % sc->time_rate == 0);
            st->duration /= sc->time_rate;
        }
        sc->ffindex = i;
        mov_build_index(mov, st);
    }

    for(i=0; i<mov->total_streams; i++) {
        /* Do not need those anymore. */
        av_freep(&mov->streams[i]->chunk_offsets);
        av_freep(&mov->streams[i]->sample_to_chunk);
        av_freep(&mov->streams[i]->sample_sizes);
        av_freep(&mov->streams[i]->keyframes);
        av_freep(&mov->streams[i]->stts_data);
    }
    av_freep(&mov->mdat_list);
    return 0;
}

static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    MOVContext *mov = s->priv_data;
    MOVStreamContext *sc = 0;
    AVIndexEntry *sample = 0;
    int64_t best_dts = INT64_MAX;
    int i;

    for (i = 0; i < mov->total_streams; i++) {
        MOVStreamContext *msc = mov->streams[i];

        if (s->streams[i]->discard != AVDISCARD_ALL && msc->current_sample < msc->sample_count) {
            AVIndexEntry *current_sample = &s->streams[i]->index_entries[msc->current_sample];
            int64_t dts = av_rescale(current_sample->timestamp * (int64_t)msc->time_rate, AV_TIME_BASE, msc->time_scale);

            dprintf(s, "stream %d, sample %d, dts %"PRId64"\n", i, msc->current_sample, dts);
            if (dts < best_dts) {
                sample = current_sample;
                best_dts = dts;
                sc = msc;
            }
        }
    }
    if (!sample)
        return -1;
    /* must be done just before reading, to avoid infinite loop on sample */
    sc->current_sample++;
    if (sample->pos >= url_fsize(&s->pb)) {
        av_log(mov->fc, AV_LOG_ERROR, "stream %d, offset 0x%"PRIx64": partial file\n", sc->ffindex, sample->pos);
        return -1;
    }
#ifdef CONFIG_DV_DEMUXER
    if (sc->dv_audio_container) {
        dv_get_packet(mov->dv_demux, pkt);
        dprintf(s, "dv audio pkt size %d\n", pkt->size);
    } else {
#endif
        url_fseek(&s->pb, sample->pos, SEEK_SET);
        av_get_packet(&s->pb, pkt, sample->size);
#ifdef CONFIG_DV_DEMUXER
        if (mov->dv_demux) {
            void *pkt_destruct_func = pkt->destruct;
            dv_produce_packet(mov->dv_demux, pkt, pkt->data, pkt->size);
            pkt->destruct = pkt_destruct_func;
        }
    }
#endif
    pkt->stream_index = sc->ffindex;
    pkt->dts = sample->timestamp;
    if (sc->ctts_data) {
        assert(sc->ctts_data[sc->sample_to_ctime_index].duration % sc->time_rate == 0);
        pkt->pts = pkt->dts + sc->ctts_data[sc->sample_to_ctime_index].duration / sc->time_rate;
        /* update ctts context */
        sc->sample_to_ctime_sample++;
        if (sc->sample_to_ctime_index < sc->ctts_count && sc->ctts_data[sc->sample_to_ctime_index].count == sc->sample_to_ctime_sample) {
            sc->sample_to_ctime_index++;
            sc->sample_to_ctime_sample = 0;
        }
    } else {
        pkt->pts = pkt->dts;
    }
    pkt->flags |= sample->flags & AVINDEX_KEYFRAME ? PKT_FLAG_KEY : 0;
    pkt->pos = sample->pos;
    dprintf(s, "stream %d, pts %"PRId64", dts %"PRId64", pos 0x%"PRIx64", duration %d\n", pkt->stream_index, pkt->pts, pkt->dts, pkt->pos, pkt->duration);
    return 0;
}

static int mov_seek_stream(AVStream *st, int64_t timestamp, int flags)
{
    MOVStreamContext *sc = st->priv_data;
    int sample, time_sample;
    int i;

    sample = av_index_search_timestamp(st, timestamp, flags);
    dprintf(st->codec, "stream %d, timestamp %"PRId64", sample %d\n", st->index, timestamp, sample);
    if (sample < 0) /* not sure what to do */
        return -1;
    sc->current_sample = sample;
    dprintf(st->codec, "stream %d, found sample %d\n", st->index, sc->current_sample);
    /* adjust ctts index */
    if (sc->ctts_data) {
        time_sample = 0;
        for (i = 0; i < sc->ctts_count; i++) {
            int next = time_sample + sc->ctts_data[i].count;
            if (next > sc->current_sample) {
                sc->sample_to_ctime_index = i;
                sc->sample_to_ctime_sample = sc->current_sample - time_sample;
                break;
            }
            time_sample = next;
        }
    }
    return sample;
}

static int mov_read_seek(AVFormatContext *s, int stream_index, int64_t sample_time, int flags)
{
    AVStream *st;
    int64_t seek_timestamp, timestamp;
    int sample;
    int i;

    if (stream_index >= s->nb_streams)
        return -1;

    st = s->streams[stream_index];
    sample = mov_seek_stream(st, sample_time, flags);
    if (sample < 0)
        return -1;

    /* adjust seek timestamp to found sample timestamp */
    seek_timestamp = st->index_entries[sample].timestamp;

    for (i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        if (stream_index == i || st->discard == AVDISCARD_ALL)
            continue;

        timestamp = av_rescale_q(seek_timestamp, s->streams[stream_index]->time_base, st->time_base);
        mov_seek_stream(st, timestamp, flags);
    }
    return 0;
}

static int mov_read_close(AVFormatContext *s)
{
    int i;
    MOVContext *mov = s->priv_data;
    for(i=0; i<mov->total_streams; i++) {
        av_freep(&mov->streams[i]->ctts_data);
        av_freep(&mov->streams[i]);
    }
    if(mov->dv_demux){
        for(i=0; i<mov->dv_fctx->nb_streams; i++){
            av_freep(&mov->dv_fctx->streams[i]->codec);
            av_freep(&mov->dv_fctx->streams[i]);
        }
        av_freep(&mov->dv_fctx);
        av_freep(&mov->dv_demux);
    }
    return 0;
}

AVInputFormat mov_demuxer = {
    "mov,mp4,m4a,3gp,3g2,mj2",
    "QuickTime/MPEG4/Motion JPEG 2000 format",
    sizeof(MOVContext),
    mov_probe,
    mov_read_header,
    mov_read_packet,
    mov_read_close,
    mov_read_seek,
};