mov.c

F:图像处理资料264264书籍ffmpeg-0.4.9-pre1VideoStream.rar 一个视频解压缩源代码

    if(sc) {
        av_free(sc->chunk_offsets);
        av_free(sc->sample_to_chunk);
        av_free(sc->sample_sizes);
        av_free(sc->keyframes);
        av_free(sc->header_data);
        av_free(sc->stts_data);        
        av_free(sc);
    }
}

static inline uint32_t mov_to_tag(uint8_t *buf)
{
    return MKTAG(buf[0], buf[1], buf[2], buf[3]);
}

static inline uint32_t to_be32(uint8_t *buf)
{
    return (buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3];
}

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

    /* check file header */
    if (p->buf_size <= 12)
        return 0;
    offset = 0;
    for(;;) {
        /* ignore invalid offset */
        if ((offset + 8) > (unsigned int)p->buf_size)
            return 0;
        tag = mov_to_tag(p->buf + offset + 4);
        switch(tag) {
        case MKTAG( 'm', 'o', 'o', 'v' ):
        case MKTAG( 'w', 'i', 'd', 'e' ):
        case MKTAG( 'f', 'r', 'e', 'e' ):
        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;
        case MKTAG( 'f', 't', 'y', 'p' ):
        case MKTAG( 's', 'k', 'i', 'p' ):
            offset = to_be32(p->buf+offset) + offset;
            break;
        default:
            /* unrecognized tag */
            return 0;
        }
    }
    return 0;
}

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

    mov->fc = s;
    mov->parse_table = mov_default_parse_table;
#if 0
    /* XXX: I think we should auto detect */
    if(s->iformat->name[1] == 'p')
        mov->mp4 = 1;
#endif
    if(!url_is_streamed(pb)) /* .mov and .mp4 aren't streamable anyway (only progressive download if moov is before mdat) */
	atom.size = url_filesize(url_fileno(pb));
    else
	atom.size = 0x7FFFFFFFFFFFFFFFLL;

#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "filesz=%Ld\n", atom.size);
#endif

    /* 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:%lld\n",
		err, mov->found_moov, mov->found_mdat, url_ftell(pb));
	return -1;
    }
#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "on_parse_exit_offset=%d\n", (int) url_ftell(pb));
#endif
    /* 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->next_chunk_offset = mov->mdat_offset; /* initialise reading */

#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "mdat_reset_offset=%d\n", (int) url_ftell(pb));
#endif

#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "streams= %d\n", s->nb_streams);
#endif
    mov->total_streams = nb = s->nb_streams;

#if 1
    for(i=0; i<s->nb_streams;) {
        if(s->streams[i]->codec.codec_type == CODEC_TYPE_MOV_OTHER) {/* not audio, not video, delete */
            av_free(s->streams[i]);
            for(j=i+1; j<s->nb_streams; j++)
                s->streams[j-1] = s->streams[j];
            s->nb_streams--;
        } else
            i++;
    }
    for(i=0; i<s->nb_streams;i++) {
        MOVStreamContext *sc;
        sc = (MOVStreamContext *)s->streams[i]->priv_data;
        sc->ffindex = i;
        sc->is_ff_stream = 1;
    }
#endif
#ifdef DEBUG
    av_log(NULL, AV_LOG_DEBUG, "real streams= %d\n", s->nb_streams);
#endif
    return 0;
}

/* Yes, this is ugly... I didn't write the specs of QT :p */
/* XXX:remove useless commented code sometime */
static int mov_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    MOVContext *mov = (MOVContext *) s->priv_data;
    MOVStreamContext *sc;
    int64_t offset = 0x0FFFFFFFFFFFFFFFLL;
    int i, a, b, m;
    int size;
    size = 0x0FFFFFFF;

#ifdef MOV_SPLIT_CHUNKS
    if (mov->partial) {

        int idx;

	sc = mov->partial;
	idx = sc->sample_to_chunk_index;

        if (idx < 0) return 0;
	size = sc->sample_sizes[sc->current_sample];

        sc->current_sample++;
        sc->left_in_chunk--;

        if (sc->left_in_chunk <= 0)
            mov->partial = 0;
        offset = mov->next_chunk_offset;
        /* extract the sample */

        goto readchunk;
    }
#endif

again:
    sc = 0;
    for(i=0; i<mov->total_streams; i++) {
	MOVStreamContext *msc = mov->streams[i];
	//av_log(NULL, AV_LOG_DEBUG, "MOCHUNK %ld  %d   %p  pos:%Ld\n", mov->streams[i]->next_chunk, mov->total_streams, mov->streams[i], url_ftell(&s->pb));
        if ((msc->next_chunk < msc->chunk_count) && msc->next_chunk >= 0
	   && (msc->chunk_offsets[msc->next_chunk] < offset)) {
	    sc = msc;
	    offset = msc->chunk_offsets[msc->next_chunk];
	    //av_log(NULL, AV_LOG_DEBUG, "SELETED  %Ld  i:%d\n", offset, i);
        }
    }
    if (!sc || offset==0x0FFFFFFFFFFFFFFFLL)
	return -1;

    sc->next_chunk++;

    if(mov->next_chunk_offset < offset) { /* some meta data */
        url_fskip(&s->pb, (offset - mov->next_chunk_offset));
        mov->next_chunk_offset = offset;
    }

//av_log(NULL, AV_LOG_DEBUG, "chunk: [%i] %lli -> %lli\n", st_id, mov->next_chunk_offset, offset);
    if(!sc->is_ff_stream) {
        url_fskip(&s->pb, (offset - mov->next_chunk_offset));
        mov->next_chunk_offset = offset;
	offset = 0x0FFFFFFFFFFFFFFFLL;
        goto again;
    }

    /* now get the chunk size... */

    for(i=0; i<mov->total_streams; i++) {
	MOVStreamContext *msc = mov->streams[i];
	if ((msc->next_chunk < msc->chunk_count)
	    && ((msc->chunk_offsets[msc->next_chunk] - offset) < size))
	    size = msc->chunk_offsets[msc->next_chunk] - offset;
    }

#ifdef MOV_MINOLTA_FIX
    //Make sure that size is according to sample_size (Needed by .mov files 
    //created on a Minolta Dimage Xi where audio chunks contains waste data in the end)
    //Maybe we should really not only check sc->sample_size, but also sc->sample_sizes
    //but I have no such movies
    if (sc->sample_size > 0) { 
        int foundsize=0;
        for(i=0; i<(sc->sample_to_chunk_sz); i++) {
            if( (sc->sample_to_chunk[i].first)<=(sc->next_chunk) && (sc->sample_size>0) )
            {
		// I can't figure out why for PCM audio sample_size is always 1
		// (it should actually be channels*bits_per_second/8) but it is.
		AVCodecContext* cod = &s->streams[sc->ffindex]->codec;
                if (sc->sample_size == 1 && (cod->codec_id == CODEC_ID_PCM_S16BE || cod->codec_id == CODEC_ID_PCM_S16LE))
		    foundsize=(sc->sample_to_chunk[i].count*cod->channels*cod->bits_per_sample)/8;
		else
		    foundsize=sc->sample_to_chunk[i].count*sc->sample_size;
            }
#ifdef DEBUG
            /*av_log(NULL, AV_LOG_DEBUG, "sample_to_chunk first=%ld count=%ld, id=%ld\n", sc->sample_to_chunk[i].first, sc->sample_to_chunk[i].count, sc->sample_to_chunk[i].id);*/
#endif
        }
        if( (foundsize>0) && (foundsize<size) )
        {
#ifdef DEBUG
            /*av_log(NULL, AV_LOG_DEBUG, "this size should actually be %d\n",foundsize);*/
#endif
            size=foundsize;
        }
    }
#endif //MOV_MINOLTA_FIX

#ifdef MOV_SPLIT_CHUNKS
    /* split chunks into samples */
    if (sc->sample_size == 0) {
        int idx = sc->sample_to_chunk_index;
        if ((idx + 1 < sc->sample_to_chunk_sz)
	    && (sc->next_chunk >= sc->sample_to_chunk[idx + 1].first))
           idx++;
        sc->sample_to_chunk_index = idx;
        if (idx >= 0 && sc->sample_to_chunk[idx].count != 1) {
	    mov->partial = sc;
            /* we'll have to get those samples before next chunk */
            sc->left_in_chunk = sc->sample_to_chunk[idx].count - 1;
            size = sc->sample_sizes[sc->current_sample];
        }

        sc->current_sample++;
    }
#endif

readchunk:
//av_log(NULL, AV_LOG_DEBUG, "chunk: [%i] %lli -> %lli (%i)\n", st_id, offset, offset + size, size);
    if(size == 0x0FFFFFFF)
        size = mov->mdat_size + mov->mdat_offset - offset;
    if(size < 0)
        return -1;
    if(size == 0)
        return -1;
    url_fseek(&s->pb, offset, SEEK_SET);

    //av_log(NULL, AV_LOG_DEBUG, "READCHUNK hlen: %d  %d off: %Ld   pos:%Ld\n", size, sc->header_len, offset, url_ftell(&s->pb));
    if (sc->header_len > 0) {
        av_new_packet(pkt, size + sc->header_len);
        memcpy(pkt->data, sc->header_data, sc->header_len);
        get_buffer(&s->pb, pkt->data + sc->header_len, size);
        /* free header */
        av_freep(&sc->header_data);
        sc->header_len = 0;
    } else {
        av_new_packet(pkt, size);
        get_buffer(&s->pb, pkt->data, pkt->size);
    }
    pkt->stream_index = sc->ffindex;
    
    // If the keyframes table exists, mark any samples that are in the table as key frames.
    // If no table exists, treat very sample as a key frame.
    if (sc->keyframes) {        
        a = 0;
        b = sc->keyframe_count - 1;
        
        while (a < b) {
            m = (a + b + 1) >> 1;
            if (sc->keyframes[m] > sc->current_sample) {
                b = m - 1;
            } else {
                a = m;
            }    
        }
        
        if (sc->keyframes[a] == sc->current_sample)
            pkt->flags |= PKT_FLAG_KEY;
    }
    else
        pkt->flags |= PKT_FLAG_KEY;

#ifdef DEBUG
/*
    av_log(NULL, AV_LOG_DEBUG, "Packet (%d, %d, %ld) ", pkt->stream_index, st_id, pkt->size);
    for(i=0; i<8; i++)
        av_log(NULL, AV_LOG_DEBUG, "%02x ", pkt->data[i]);
    for(i=0; i<8; i++)
        av_log(NULL, AV_LOG_DEBUG, "%c ", (pkt->data[i]) & 0x7F);
    puts("");
*/
#endif

    mov->next_chunk_offset = offset + size;

    return 0;
}

#if defined(MOV_SPLIT_CHUNKS) && defined(MOV_SEEK)
/**
 * Seek method based on the one described in the Appendix C of QTFileFormat.pdf
 */
static int mov_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp)
{
    MOVContext* mov = (MOVContext *) s->priv_data;
    MOVStreamContext* sc;
    int32_t i, a, b, m;
    int64_t sample_time;
    int64_t start_time;
    int32_t seek_sample, sample;
    int32_t duration;
    int32_t count;
    int32_t chunk;
    int32_t left_in_chunk;
    int64_t chunk_file_offset;
    int64_t sample_file_offset;
    int32_t first_chunk_sample;
    int32_t sample_to_chunk_idx;
    int mov_idx;

    // Find the corresponding mov stream
    for (mov_idx = 0; mov_idx < mov->total_streams; mov_idx++)
        if (mov->streams[mov_idx]->ffindex == stream_index)
            break;
    if (mov_idx == mov->total_streams) {
        av_log(s, AV_LOG_ERROR, "mov: requested stream was not found in mov streams (idx=%i)\n", stream_index);
        return -1;
    }
    sc = mov->streams[mov_idx];

    // Step 1. Find the edit that contains the requested time (elst)
    if (sc->edit_count) {
        // FIXME should handle edit list
        av_log(s, AV_LOG_ERROR, "mov: does not handle seeking in files that contain edit list (c:%d)\n", sc->edit_count);
        return -1;
    }

    // Step 2. Find the corresponding sample using the Time-to-sample atom (stts) */
#ifdef DEBUG
  av_log(s, AV_LOG_DEBUG, "Searching for time %li in stream #%i (time_scale=%i)\n", (long)timestamp, mov_idx, sc->time_scale);
#endif
    // convert timestamp from time_base unit to timescale unit
    sample_time = av_rescale( timestamp,
                            (int64_t)sc->time_scale * s->streams[stream_index]->time_base.num,
                            (int64_t)s->streams[stream_index]->time_base.den);
    start_time = 0; // FIXME use elst atom
    sample = 1; // sample are 0 based in table
#ifdef DEBUG
    av_log(s, AV_LOG_DEBUG, "Searching for sample_time %li \n", (long)sample_time);
#endif
    for (i = 0; i < sc->stts_count; i++) {
        count = (uint32_t)(sc->stts_data[i]>>32);
        duration = (uint32_t)(sc->stts_data[i]&0xffff);
//av_log(s, AV_LOG_DEBUG, "> sample_time %lli \n", (long)sample_time);                
//av_log(s, AV_LOG_DEBUG, "> count=%i duration=%i\n", count, duration);        
        if ((start_time + count*duration) > sample_time) {
            sample += (sample_time - start_time) / duration;
            break;
        }
        sample += count;
        start_time += count * duration;
    }   
    /* NOTE: despite what qt doc say, the dt value (Display Time in qt vocabulary) computed with the stts atom
       is a decoding time stamp (dts