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

        get_be16(pb); /* index */

        /* for MPEG4: set codec type by looking for it */
        id = codec_get_id(mov_video_tags, format);
        if (id >= 0) {
            AVCodec *codec;
	    codec = avcodec_find_decoder(id);
            if (codec)
		st->codec.codec_type = codec->type;
        }
#ifdef DEBUG
        av_log(NULL, AV_LOG_DEBUG, "size=%d 4CC= %c%c%c%c codec_type=%d\n",
               size,
               (format >> 0) & 0xff,
               (format >> 8) & 0xff,
               (format >> 16) & 0xff,
               (format >> 24) & 0xff,
               st->codec.codec_type);
#endif
	st->codec.codec_tag = format;
	if(st->codec.codec_type==CODEC_TYPE_VIDEO) {
	    MOV_atom_t a = { 0, 0, 0 };
            st->codec.codec_id = id;
            get_be16(pb); /* version */
            get_be16(pb); /* revision level */
            get_be32(pb); /* vendor */
            get_be32(pb); /* temporal quality */
            get_be32(pb); /* spacial quality */
            st->codec.width = get_be16(pb); /* width */
            st->codec.height = get_be16(pb); /* height */
#if 1
            if (st->codec.codec_id == CODEC_ID_MPEG4) {
                /* in some MPEG4 the width/height are not correct, so
                   we ignore this info */
                st->codec.width = 0;
                st->codec.height = 0;
            }
#endif
            get_be32(pb); /* horiz resolution */
            get_be32(pb); /* vert resolution */
            get_be32(pb); /* data size, always 0 */
            frames_per_sample = get_be16(pb); /* frames per samples */
#ifdef DEBUG
	    av_log(NULL, AV_LOG_DEBUG, "frames/samples = %d\n", frames_per_sample);
#endif
	    get_buffer(pb, (uint8_t *)st->codec.codec_name, 32); /* codec name */

	    st->codec.bits_per_sample = get_be16(pb); /* depth */
            st->codec.color_table_id = get_be16(pb); /* colortable id */

/*          These are set in mov_read_stts and might already be set!
            st->codec.frame_rate      = 25;
            st->codec.frame_rate_base = 1;
*/
	    size -= (16+8*4+2+32+2*2);
#if 0
	    while (size >= 8) {
		MOV_atom_t a;
                int64_t start_pos;

		a.size = get_be32(pb);
		a.type = get_le32(pb);
		size -= 8;
#ifdef DEBUG
                av_log(NULL, AV_LOG_DEBUG, "VIDEO: atom_type=%c%c%c%c atom.size=%Ld size_left=%d\n",
                       (a.type >> 0) & 0xff,
                       (a.type >> 8) & 0xff,
                       (a.type >> 16) & 0xff,
                       (a.type >> 24) & 0xff,
		       a.size, size);
#endif
                start_pos = url_ftell(pb);

		switch(a.type) {
                case MKTAG('e', 's', 'd', 's'):
                    {
                        int tag, len;
                        /* Well, broken but suffisant for some MP4 streams */
                        get_be32(pb); /* version + flags */
			len = mov_mp4_read_descr(pb, &tag);
                        if (tag == 0x03) {
                            /* MP4ESDescrTag */
                            get_be16(pb); /* ID */
                            get_byte(pb); /* priority */
			    len = mov_mp4_read_descr(pb, &tag);
                            if (tag != 0x04)
                                goto fail;
                            /* MP4DecConfigDescrTag */
                            get_byte(pb); /* objectTypeId */
                            get_be32(pb); /* streamType + buffer size */
			    get_be32(pb); /* max bit rate */
                            get_be32(pb); /* avg bit rate */
                            len = mov_mp4_read_descr(pb, &tag);
                            if (tag != 0x05)
                                goto fail;
                            /* MP4DecSpecificDescrTag */
#ifdef DEBUG
                            av_log(NULL, AV_LOG_DEBUG, "Specific MPEG4 header len=%d\n", len);
#endif
                            sc->header_data = av_mallocz(len);
                            if (sc->header_data) {
                                get_buffer(pb, sc->header_data, len);
				sc->header_len = len;
                            }
                        }
                        /* in any case, skip garbage */
                    }
                    break;
                default:
                    break;
                }
	    fail:
		av_log(NULL, AV_LOG_DEBUG, "ATOMENEWSIZE %Ld   %d\n", atom.size, url_ftell(pb) - start_pos);
		if (atom.size > 8) {
		    url_fskip(pb, (atom.size - 8) -
			      ((url_ftell(pb) - start_pos)));
		    size -= atom.size - 8;
		}
	    }
            if (size > 0) {
                /* unknown extension */
                url_fskip(pb, size);
            }
#else

            /* figure out the palette situation */
            color_depth = st->codec.bits_per_sample & 0x1F;
            color_greyscale = st->codec.bits_per_sample & 0x20;

            /* if the depth is 2, 4, or 8 bpp, file is palettized */
            if ((color_depth == 2) || (color_depth == 4) || 
                (color_depth == 8)) {

                if (color_greyscale) {

                    /* compute the greyscale palette */
                    color_count = 1 << color_depth;
                    color_index = 255;
                    color_dec = 256 / (color_count - 1);
                    for (j = 0; j < color_count; j++) {
                        r = g = b = color_index;
                        c->palette_control.palette[j] =
                            (r << 16) | (g << 8) | (b);
                        color_index -= color_dec;
                        if (color_index < 0)
                            color_index = 0;
                    }

                } else if (st->codec.color_table_id & 0x08) {

                    /* if flag bit 3 is set, use the default palette */
                    color_count = 1 << color_depth;
                    if (color_depth == 2)
                        color_table = ff_qt_default_palette_4;
                    else if (color_depth == 4)
                        color_table = ff_qt_default_palette_16;
                    else
                        color_table = ff_qt_default_palette_256;

                    for (j = 0; j < color_count; j++) {
                        r = color_table[j * 4 + 0];
                        g = color_table[j * 4 + 1];
                        b = color_table[j * 4 + 2];
                        c->palette_control.palette[j] =
                            (r << 16) | (g << 8) | (b);
                    }

                } else {

                    /* load the palette from the file */
                    color_start = get_be32(pb);
                    color_count = get_be16(pb);
                    color_end = get_be16(pb);
                    for (j = color_start; j <= color_end; j++) {
                        /* each R, G, or B component is 16 bits;
                         * only use the top 8 bits; skip alpha bytes
                         * up front */
                        get_byte(pb);
                        get_byte(pb);
                        r = get_byte(pb);
                        get_byte(pb);
                        g = get_byte(pb);
                        get_byte(pb);
                        b = get_byte(pb);
                        get_byte(pb);
                        c->palette_control.palette[j] =
                            (r << 16) | (g << 8) | (b);
                    }
                }

                st->codec.palctrl = &c->palette_control;
                st->codec.palctrl->palette_changed = 1;
            } else
                st->codec.palctrl = NULL;

            a.size = size;
	    mov_read_default(c, pb, a);
#endif
	} else {
            st->codec.codec_id = codec_get_id(mov_audio_tags, format);
	    if(st->codec.codec_id==CODEC_ID_AMR_NB || st->codec.codec_id==CODEC_ID_AMR_WB) //from TS26.244
	    {
#ifdef DEBUG
               av_log(NULL, AV_LOG_DEBUG, "AMR-NB or AMR-WB audio identified!!\n");
#endif
               get_be32(pb);get_be32(pb); //Reserved_8
               get_be16(pb);//Reserved_2
               get_be16(pb);//Reserved_2
               get_be32(pb);//Reserved_4
               get_be16(pb);//TimeScale
               get_be16(pb);//Reserved_2

                //AMRSpecificBox.(10 bytes)
               
               get_be32(pb); //size
               get_be32(pb); //type=='damr'
               get_be32(pb); //vendor
               get_byte(pb); //decoder version
               get_be16(pb); //mode_set
               get_byte(pb); //mode_change_period
               get_byte(pb); //frames_per_sample

               st->duration = AV_NOPTS_VALUE;//Not possible to get from this info, must count number of AMR frames
               if(st->codec.codec_id==CODEC_ID_AMR_NB)
               {
                   st->codec.sample_rate=8000;
                   st->codec.channels=1;
               }
               else //AMR-WB
               {
                   st->codec.sample_rate=16000;
                   st->codec.channels=1;
               }
               st->codec.bits_per_sample=16;
               st->codec.bit_rate=0; /*It is not possible to tell this before we have 
                                       an audio frame and even then every frame can be different*/
	    }
            else if( st->codec.codec_tag == MKTAG( 'm', 'p', '4', 's' ))
            {
                //This is some stuff for the hint track, lets ignore it!
                //Do some mp4 auto detect.
                c->mp4=1;
                size-=(16);
                url_fskip(pb, size); /* The mp4s atom also contians a esds atom that we can skip*/
            }
            else if( st->codec.codec_tag == MKTAG( 'm', 'p', '4', 'a' ))
            {
                /* Handle mp4 audio tag */
                get_be32(pb); /* version */
                get_be32(pb);
                st->codec.channels = get_be16(pb); /* channels */
                st->codec.bits_per_sample = get_be16(pb); /* bits per sample */
                get_be32(pb);
                st->codec.sample_rate = get_be16(pb); /* sample rate, not always correct */
                get_be16(pb);
                c->mp4=1;
		{
                MOV_atom_t a = { format, url_ftell(pb), size - (20 + 20 + 8) };
                mov_read_default(c, pb, a);
		}
                /* Get correct sample rate from extradata */
                if(st->codec.extradata_size) {
                   const int samplerate_table[] = {
                     96000, 88200, 64000, 48000, 44100, 32000, 
                     24000, 22050, 16000, 12000, 11025, 8000,
                     7350, 0, 0, 0
                   };
                   unsigned char *px = st->codec.extradata;
                   // 5 bits objectTypeIndex, 4 bits sampleRateIndex, 4 bits channels
                   int samplerate_index = ((px[0] & 7) << 1) + ((px[1] >> 7) & 1);
                   st->codec.sample_rate = samplerate_table[samplerate_index];
                }
            }
	    else if(size>=(16+20))
	    {//16 bytes read, reading atleast 20 more
#ifdef DEBUG
                av_log(NULL, AV_LOG_DEBUG, "audio size=0x%X\n",size);
#endif
                uint16_t version = get_be16(pb); /* version */
                get_be16(pb); /* revision level */
                get_be32(pb); /* vendor */

                st->codec.channels = get_be16(pb);		/* channel count */
	        st->codec.bits_per_sample = get_be16(pb);	/* sample size */

                /* handle specific s8 codec */
                get_be16(pb); /* compression id = 0*/
                get_be16(pb); /* packet size = 0 */

                st->codec.sample_rate = ((get_be32(pb) >> 16));
	        //av_log(NULL, AV_LOG_DEBUG, "CODECID %d  %d  %.4s\n", st->codec.codec_id, CODEC_ID_PCM_S16BE, (char*)&format);

	        switch (st->codec.codec_id) {
	        case CODEC_ID_PCM_S16BE:
		    if (st->codec.bits_per_sample == 8)
		        st->codec.codec_id = CODEC_ID_PCM_S8;
                    /* fall */
	        case CODEC_ID_PCM_U8:
		    st->codec.bit_rate = st->codec.sample_rate * 8;
		    break;
	        default:
                    ;
	        }

                //Read QT version 1 fields. In version 0 theese dont exist
#ifdef DEBUG
                av_log(NULL, AV_LOG_DEBUG, "version =%d mp4=%d\n",version,c->mp4);
                av_log(NULL, AV_LOG_DEBUG, "size-(16+20+16)=%d\n",size-(16+20+16));
#endif
                if((version==1) && size>=(16+20+16))
                {
                    get_be32(pb); /* samples per packet */
                    get_be32(pb); /* bytes per packet */
                    get_be32(pb); /* bytes per frame */
                    get_be32(pb); /* bytes per sample */
                    if(size>(16+20+16))
                    {
                        //Optional, additional atom-based fields
#ifdef DEBUG
                        av_log(NULL, AV_LOG_DEBUG, "offest=0x%X, sizeleft=%d=0x%x,format=%c%c%c%c\n",(int)url_ftell(pb),size - (16 + 20 + 16 ),size - (16 + 20 + 16 ),
                            (format >> 0) & 0xff,
                            (format >> 8) & 0xff,
                            (format >> 16) & 0xff,
                            (format >> 24) & 0xff);
#endif
                        MOV_atom_t a = { format, url_ftell(pb), size - (16 + 20 + 16 + 8) };
                        mov_read_default(c, pb, a);
                    }
                }
                else
                {
                    //We should be down to 0 bytes here, but lets make sure.
                    size-=(16+20);
#ifdef DEBUG
                    if(size>0)
                        av_log(NULL, AV_LOG_DEBUG, "skipping 0x%X bytes\n",size-(16+20));
#endif
                    url_fskip(pb, size);
                }
            }
            else
            {
                size-=16;
                //Unknown size, but lets do our best and skip the rest.
#ifdef DEBUG
                av_log(NULL, AV_LOG_DEBUG, "Strange size, skipping 0x%X bytes\n",size);
#endif
                url_fskip(pb, size);
            }
        }
    }

    return 0;
}

static int mov_read_stsc(MOVContext *c, ByteIOContext *pb, MOV_atom_t atom)
{
    AVStream *st = c->fc->streams[c->fc->nb_streams-1];
    MOVStreamContext *sc = (MOVStreamContext *)st->priv_data;
    int entries, i;

    print_atom("stsc", atom);

    get_byte(pb); /* version */
    get_byte(pb); get_byte(pb); get_byte(pb); /* flags */

    entries = get_be32(pb);
#ifdef DEBUG
av_log(NULL, AV_LOG_DEBUG, "track[%i].stsc.entries = %i\n", c->fc->nb_streams-1, entries);
#endif
    sc->sample_to_chunk_sz = entries;
    sc->sample_to_chunk = (MOV_sample_to_chunk_tbl*) av_malloc(entries * sizeof(MOV_sample_to_chunk_tbl));
    if (!sc->sample_to_chunk)
        return -1;
    for(i=0; i<entries; i++) {
        sc->sample_to_chunk[i].first = get_be32(pb);
        sc->sample_to_chunk[i].count = get_be32(pb);
        sc->sample_to_chunk[i].id = get_be32(pb);
#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