C++ skip_bits1函数代码示例

/* don't understand why they choose a different header ! */
int ff_intel_h263_decode_picture_header(MpegEncContext *s)
{
    int format;

    /* picture header */
    if (get_bits_long(&s->gb, 22) != 0x20) {
        av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
        return -1;
    }
    s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */

    if (get_bits1(&s->gb) != 1) {
        av_log(s->avctx, AV_LOG_ERROR, "Bad marker\n");
        return -1;      /* marker */
    }
    if (get_bits1(&s->gb) != 0) {
        av_log(s->avctx, AV_LOG_ERROR, "Bad H263 id\n");
        return -1;      /* h263 id */
    }
    skip_bits1(&s->gb);         /* split screen off */
    skip_bits1(&s->gb);         /* camera  off */
    skip_bits1(&s->gb);         /* freeze picture release off */

    format = get_bits(&s->gb, 3);
    if (format == 0 || format == 6) {
        av_log(s->avctx, AV_LOG_ERROR, "Intel H263 free format not supported\n");
        return -1;
    }
    s->h263_plus = 0;

    s->pict_type = AV_PICTURE_TYPE_I + get_bits1(&s->gb);

    s->unrestricted_mv = get_bits1(&s->gb);
    s->h263_long_vectors = s->unrestricted_mv;

    if (get_bits1(&s->gb) != 0) {
        av_log(s->avctx, AV_LOG_ERROR, "SAC not supported\n");
        return -1;      /* SAC: off */
    }
    s->obmc= get_bits1(&s->gb);
    s->pb_frame = get_bits1(&s->gb);

    if (format < 6) {
        s->width = ff_h263_format[format][0];
        s->height = ff_h263_format[format][1];
        s->avctx->sample_aspect_ratio.num = 12;
        s->avctx->sample_aspect_ratio.den = 11;
    } else {
        format = get_bits(&s->gb, 3);
        if(format == 0 || format == 7){
            av_log(s->avctx, AV_LOG_ERROR, "Wrong Intel H263 format\n");
            return -1;
        }
        if(get_bits(&s->gb, 2))
            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
        s->loop_filter = get_bits1(&s->gb);
        if(get_bits1(&s->gb))
            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
        if(get_bits1(&s->gb))
            s->pb_frame = 2;
        if(get_bits(&s->gb, 5))
            av_log(s->avctx, AV_LOG_ERROR, "Bad value for reserved field\n");
        if(get_bits(&s->gb, 5) != 1)
            av_log(s->avctx, AV_LOG_ERROR, "Invalid marker\n");
    }
    if(format == 6){
        int ar = get_bits(&s->gb, 4);
        skip_bits(&s->gb, 9); // display width
        skip_bits1(&s->gb);
        skip_bits(&s->gb, 9); // display height
        if(ar == 15){
            s->avctx->sample_aspect_ratio.num = get_bits(&s->gb, 8); // aspect ratio - width
            s->avctx->sample_aspect_ratio.den = get_bits(&s->gb, 8); // aspect ratio - height
        } else {
            s->avctx->sample_aspect_ratio = ff_h263_pixel_aspect[ar];
        }
        if (s->avctx->sample_aspect_ratio.num == 0)
            av_log(s->avctx, AV_LOG_ERROR, "Invalid aspect ratio.\n");
    }

    s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);
    skip_bits1(&s->gb); /* Continuous Presence Multipoint mode: off */

    if(s->pb_frame){
        skip_bits(&s->gb, 3); //temporal reference for B-frame
        skip_bits(&s->gb, 2); //dbquant
    }

    /* PEI */
    while (get_bits1(&s->gb) != 0) {
        skip_bits(&s->gb, 8);
    }
    s->f_code = 1;

    s->y_dc_scale_table=
    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;

    ff_h263_show_pict_info(s);

//.........这里部分代码省略.........

int ff_h264_decode_ref_pic_marking(H264Context *h, GetBitContext *gb,
                                   int first_slice)
{
    int i, ret;
    MMCO mmco_temp[MAX_MMCO_COUNT], *mmco = mmco_temp;
    int mmco_index = 0;

    if (h->nal_unit_type == NAL_IDR_SLICE) { // FIXME fields
        skip_bits1(gb); // broken_link
        if (get_bits1(gb)) {
            mmco[0].opcode   = MMCO_LONG;
            mmco[0].long_arg = 0;
            mmco_index       = 1;
        }
    } else {
        if (get_bits1(gb)) { // adaptive_ref_pic_marking_mode_flag
            for (i = 0; i < MAX_MMCO_COUNT; i++) {
                MMCOOpcode opcode = get_ue_golomb_31(gb);

                mmco[i].opcode = opcode;
                if (opcode == MMCO_SHORT2UNUSED || opcode == MMCO_SHORT2LONG) {
                    mmco[i].short_pic_num =
                        (h->curr_pic_num - get_ue_golomb(gb) - 1) &
                        (h->max_pic_num - 1);
#if 0
                    if (mmco[i].short_pic_num >= h->short_ref_count ||
                            h->short_ref[ mmco[i].short_pic_num ] == NULL) {
                        av_log(s->avctx, AV_LOG_ERROR,
                               "illegal short ref in memory management control "
                               "operation %d\n", mmco);
                        return -1;
                    }
#endif
                }
                if (opcode == MMCO_SHORT2LONG || opcode == MMCO_LONG2UNUSED ||
                        opcode == MMCO_LONG || opcode == MMCO_SET_MAX_LONG) {
                    unsigned int long_arg = get_ue_golomb_31(gb);
                    if (long_arg >= 32 ||
                            (long_arg >= 16 && !(opcode == MMCO_SET_MAX_LONG &&
                                                 long_arg == 16) &&
                             !(opcode == MMCO_LONG2UNUSED && FIELD_PICTURE(h)))) {
                        av_log(h->avctx, AV_LOG_ERROR,
                               "illegal long ref in memory management control "
                               "operation %d\n", opcode);
                        return -1;
                    }
                    mmco[i].long_arg = long_arg;
                }

                if (opcode > (unsigned) MMCO_LONG) {
                    av_log(h->avctx, AV_LOG_ERROR,
                           "illegal memory management control operation %d\n",
                           opcode);
                    return -1;
                }
                if (opcode == MMCO_END)
                    break;
            }
            mmco_index = i;
        } else {
            if (first_slice) {
                ret = ff_generate_sliding_window_mmcos(h, first_slice);
                if (ret < 0 && h->avctx->err_recognition & AV_EF_EXPLODE)
                    return ret;
            }
            mmco_index = -1;
        }
    }

    if (first_slice && mmco_index != -1) {
        memcpy(h->mmco, mmco_temp, sizeof(h->mmco));
        h->mmco_index = mmco_index;
    } else if (!first_slice && mmco_index >= 0 &&
               (mmco_index != h->mmco_index ||
                check_opcodes(h->mmco, mmco_temp, mmco_index))) {
        av_log(h->avctx, AV_LOG_ERROR,
               "Inconsistent MMCO state between slices [%d, %d]\n",
               mmco_index, h->mmco_index);
        return AVERROR_INVALIDDATA;
    }

    return 0;
}

/**
 * decodes the H261 picture header.
 * @return <0 if no startcode found
 */
static int h261_decode_picture_header(H261Context *h){
    MpegEncContext * const s = &h->s;
    int format, i;
    uint32_t startcode= 0;

    for(i= get_bits_left(&s->gb); i>24; i-=1){
        startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF;

        if(startcode == 0x10)
            break;
    }

    if (startcode != 0x10){
        av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
        return -1;
    }

    /* temporal reference */
    i= get_bits(&s->gb, 5); /* picture timestamp */
    if(i < (s->picture_number&31))
        i += 32;
    s->picture_number = (s->picture_number&~31) + i;

 #ifndef _MSC_VER
   s->avctx->time_base= (AVRational){1001, 30000};
#else
	//MSVC
   s->avctx->time_base= av_create_rational(1001, 30000);
#endif
    s->current_picture.pts= s->picture_number;


    /* PTYPE starts here */
    skip_bits1(&s->gb); /* split screen off */
    skip_bits1(&s->gb); /* camera  off */
    skip_bits1(&s->gb); /* freeze picture release off */

    format = get_bits1(&s->gb);

    //only 2 formats possible
    if (format == 0){//QCIF
        s->width = 176;
        s->height = 144;
        s->mb_width = 11;
        s->mb_height = 9;
    }else{//CIF
        s->width = 352;
        s->height = 288;
        s->mb_width = 22;
        s->mb_height = 18;
    }

    s->mb_num = s->mb_width * s->mb_height;

    skip_bits1(&s->gb); /* still image mode off */
    skip_bits1(&s->gb); /* Reserved */

    /* PEI */
    while (get_bits1(&s->gb) != 0){
        skip_bits(&s->gb, 8);
    }

    // h261 has no I-FRAMES, but if we pass FF_I_TYPE for the first frame, the codec crashes if it does
    // not contain all I-blocks (e.g. when a packet is lost)
    s->pict_type = FF_P_TYPE;

    h->gob_number = 0;
    return 0;
}

/* most is hardcoded. should extend to handle all h263 streams */
static int h263_decode_picture_header(unsigned char *b_ptr)
{
    int i;

    for(i=0;i<16;i++) printf(" %02X",b_ptr[i]); printf("\n");

    buffer=b_ptr;
    bufptr=bitcnt=buf=0;

    /* picture header */
    if (get_bits(&s->gb, 22) != 0x20){
	printf("bad picture header\n");
        return -1;
    }
    skip_bits(&s->gb, 8); /* picture timestamp */

    if (get_bits1(&s->gb) != 1){
	printf("bad marker\n");
        return -1;	/* marker */
    }
    if (get_bits1(&s->gb) != 0){
	printf("bad h263 id\n");
        return -1;	/* h263 id */
    }
    skip_bits1(&s->gb);	/* split screen off */
    skip_bits1(&s->gb);	/* camera  off */
    skip_bits1(&s->gb);	/* freeze picture release off */

    format = get_bits(&s->gb, 3);

    if (format != 7) {
        printf("h263_plus = 0  format = %d\n",format);
        /* H.263v1 */
        width = h263_format[format][0];
        height = h263_format[format][1];
	printf("%d x %d\n",width,height);
//        if (!width) return -1;

	printf("pict_type=%d\n",get_bits1(&s->gb));
	printf("unrestricted_mv=%d\n",get_bits1(&s->gb));
#if 1
	printf("SAC: %d\n",get_bits1(&s->gb));
	printf("advanced prediction mode: %d\n",get_bits1(&s->gb));
	printf("PB frame: %d\n",get_bits1(&s->gb));
#else
        if (get_bits1(&s->gb) != 0)
            return -1;	/* SAC: off */
        if (get_bits1(&s->gb) != 0)
            return -1;	/* advanced prediction mode: off */
        if (get_bits1(&s->gb) != 0)
            return -1;	/* not PB frame */
#endif
	printf("qscale=%d\n",get_bits(&s->gb, 5));
        skip_bits1(&s->gb);	/* Continuous Presence Multipoint mode: off */
    } else {
        printf("h263_plus = 1\n");
        /* H.263v2 */
        if (get_bits(&s->gb, 3) != 1){
	    printf("H.263v2 A error\n");
            return -1;
	}
        if (get_bits(&s->gb, 3) != 6){ /* custom source format */
	    printf("custom source format\n");
            return -1;
	}
        skip_bits(&s->gb, 12);
        skip_bits(&s->gb, 3);
	printf("pict_type=%d\n",get_bits(&s->gb, 3) + 1);
//        if (s->pict_type != I_TYPE &&
//            s->pict_type != P_TYPE)
//            return -1;
        skip_bits(&s->gb, 7);
        skip_bits(&s->gb, 4); /* aspect ratio */
        width = (get_bits(&s->gb, 9) + 1) * 4;
        skip_bits1(&s->gb);
        height = get_bits(&s->gb, 9) * 4;
	printf("%d x %d\n",width,height);
        //if (height == 0)
        //    return -1;
	printf("qscale=%d\n",get_bits(&s->gb, 5));
    }

    /* PEI */
    while (get_bits1(&s->gb) != 0) {
        skip_bits(&s->gb, 8);
    }
//    s->f_code = 1;
//    s->width = width;
//    s->height = height;
    return 0;
}

/**
 * Decode Smacker audio data
 */
static int smka_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame_ptr, AVPacket *avpkt)
{
    AVFrame *frame     = data;
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    GetBitContext gb;
    HuffContext h[4] = { { 0 } };
    VLC vlc[4]       = { { 0 } };
    int16_t *samples;
    uint8_t *samples8;
    int val;
    int i, res, ret;
    int unp_size;
    int bits, stereo;
    int pred[2] = {0, 0};

    if (buf_size <= 4) {
        av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
        return AVERROR(EINVAL);
    }

    unp_size = AV_RL32(buf);

    init_get_bits(&gb, buf + 4, (buf_size - 4) * 8);

    if(!get_bits1(&gb)){
        av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
        *got_frame_ptr = 0;
        return 1;
    }
    stereo = get_bits1(&gb);
    bits = get_bits1(&gb);
    if (stereo ^ (avctx->channels != 1)) {
        av_log(avctx, AV_LOG_ERROR, "channels mismatch\n");
        return AVERROR(EINVAL);
    }
    if (bits && avctx->sample_fmt == AV_SAMPLE_FMT_U8) {
        av_log(avctx, AV_LOG_ERROR, "sample format mismatch\n");
        return AVERROR(EINVAL);
    }

    /* get output buffer */
    frame->nb_samples = unp_size / (avctx->channels * (bits + 1));
    if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return ret;
    }
    samples  = (int16_t *)frame->data[0];
    samples8 =            frame->data[0];

    // Initialize
    for(i = 0; i < (1 << (bits + stereo)); i++) {
        h[i].length = 256;
        h[i].maxlength = 0;
        h[i].current = 0;
        h[i].bits = av_mallocz(256 * 4);
        h[i].lengths = av_mallocz(256 * sizeof(int));
        h[i].values = av_mallocz(256 * sizeof(int));
        if (!h[i].bits || !h[i].lengths || !h[i].values) {
            ret = AVERROR(ENOMEM);
            goto error;
        }
        skip_bits1(&gb);
        if (smacker_decode_tree(&gb, &h[i], 0, 0) < 0) {
            ret = AVERROR_INVALIDDATA;
            goto error;
        }
        skip_bits1(&gb);
        if(h[i].current > 1) {
            res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
                    h[i].lengths, sizeof(int), sizeof(int),
                    h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
            if(res < 0) {
                av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
                ret = AVERROR_INVALIDDATA;
                goto error;
            }
        }
    }
    /* this codec relies on wraparound instead of clipping audio */
    if(bits) { //decode 16-bit data
        for(i = stereo; i >= 0; i--)
            pred[i] = sign_extend(av_bswap16(get_bits(&gb, 16)), 16);
        for(i = 0; i <= stereo; i++)
            *samples++ = pred[i];
        for(; i < unp_size / 2; i++) {
            if(i & stereo) {
                if(vlc[2].table)
                    res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val  = h[2].values[res];
                if(vlc[3].table)
                    res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);
                else
                    res = 0;
//.........这里部分代码省略.........

/**
 * Decode Smacker audio data
 */
static int smka_decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size)
{
    GetBitContext gb;
    HuffContext h[4];
    VLC vlc[4];
    int16_t *samples = data;
    int val;
    int i, res;
    int unp_size;
    int bits, stereo;
    int pred[2] = {0, 0};

    unp_size = AV_RL32(buf);

    init_get_bits(&gb, buf + 4, (buf_size - 4) * 8);

    if(!get_bits1(&gb)){
        av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
        *data_size = 0;
        return 1;
    }
    stereo = get_bits1(&gb);
    bits = get_bits1(&gb);
    if (unp_size & 0xC0000000 || (unp_size << !bits) > *data_size) {
        av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n");
        return -1;
    }

    memset(vlc, 0, sizeof(VLC) * 4);
    memset(h, 0, sizeof(HuffContext) * 4);
    // Initialize
    for(i = 0; i < (1 << (bits + stereo)); i++) {
        h[i].length = 256;
        h[i].maxlength = 0;
        h[i].current = 0;
        h[i].bits = av_mallocz(256 * 4);
        h[i].lengths = av_mallocz(256 * sizeof(int));
        h[i].values = av_mallocz(256 * sizeof(int));
        skip_bits1(&gb);
        smacker_decode_tree(&gb, &h[i], 0, 0);
        skip_bits1(&gb);
        if(h[i].current > 1) {
            res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
                    h[i].lengths, sizeof(int), sizeof(int),
                    h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
            if(res < 0) {
                av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
                return -1;
            }
        }
    }
    if(bits) { //decode 16-bit data
        for(i = stereo; i >= 0; i--)
            pred[i] = bswap_16(get_bits(&gb, 16));
        for(i = 0; i < stereo; i++)
            *samples++ = pred[i];
        for(i = 0; i < unp_size / 2; i++) {
            if(i & stereo) {
                if(vlc[2].table)
                    res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val  = h[2].values[res];
                if(vlc[3].table)
                    res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val |= h[3].values[res] << 8;
                pred[1] += (int16_t)val;
                *samples++ = pred[1];
            } else {
                if(vlc[0].table)
                    res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val  = h[0].values[res];
                if(vlc[1].table)
                    res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val |= h[1].values[res] << 8;
                pred[0] += val;
                *samples++ = pred[0];
            }
        }
    } else { //8-bit data
        for(i = stereo; i >= 0; i--)
            pred[i] = get_bits(&gb, 8);
        for(i = 0; i < stereo; i++)
            *samples++ = (pred[i] - 0x80) << 8;
        for(i = 0; i < unp_size; i++) {
            if(i & stereo){
                if(vlc[1].table)
                    res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                pred[1] += (int8_t)h[1].values[res];
//.........这里部分代码省略.........

//.........这里部分代码省略.........
            asset->spkr_mask_enabled = 0;
            asset->spkr_mask = 0;

            // Representation type
            asset->representation_type = get_bits(&s->gb, 3);
        }
    }

    //
    // DRC, DNC and mixing metadata
    //

    // Dynamic range coefficient presence flag
    drc_present = get_bits1(&s->gb);

    // Code for dynamic range coefficient
    if (drc_present)
        skip_bits(&s->gb, 8);

    // Dialog normalization presence flag
    if (get_bits1(&s->gb))
        // Dialog normalization code
        skip_bits(&s->gb, 5);

    // DRC for stereo downmix
    if (drc_present && asset->embedded_stereo)
        skip_bits(&s->gb, 8);

    // Mixing metadata presence flag
    if (s->mix_metadata_enabled && get_bits1(&s->gb)) {
        int nchannels_dmix;

        // External mixing flag
        skip_bits1(&s->gb);

        // Post mixing / replacement gain adjustment
        skip_bits(&s->gb, 6);

        // DRC prior to mixing
        if (get_bits(&s->gb, 2) == 3)
            // Custom code for mixing DRC
            skip_bits(&s->gb, 8);
        else
            // Limit for mixing DRC
            skip_bits(&s->gb, 3);

        // Scaling type for channels of main audio
        // Scaling parameters of main audio
        if (get_bits1(&s->gb))
            for (i = 0; i < s->nmixoutconfigs; i++)
                skip_bits_long(&s->gb, 6 * s->nmixoutchs[i]);
        else
            skip_bits_long(&s->gb, 6 * s->nmixoutconfigs);

        nchannels_dmix = asset->nchannels_total;
        if (asset->embedded_6ch)
            nchannels_dmix += 6;
        if (asset->embedded_stereo)
            nchannels_dmix += 2;

        for (i = 0; i < s->nmixoutconfigs; i++) {
            if (!s->nmixoutchs[i]) {
                av_log(s->avctx, AV_LOG_ERROR, "Invalid speaker layout mask for mixing configuration\n");
                return AVERROR_INVALIDDATA;
            }
            for (j = 0; j < nchannels_dmix; j++) {

int ff_flv_decode_picture_header(MpegEncContext *s)
{
    int format, width, height;

    /* picture header */
    if (get_bits_long(&s->gb, 17) != 1) {
        av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
        return -1;
    }
    format = get_bits(&s->gb, 5);
    if (format != 0 && format != 1) {
        av_log(s->avctx, AV_LOG_ERROR, "Bad picture format\n");
        return -1;
    }
    s->h263_flv = format+1;
    s->picture_number = get_bits(&s->gb, 8); /* picture timestamp */
    format = get_bits(&s->gb, 3);
    switch (format) {
    case 0:
        width = get_bits(&s->gb, 8);
        height = get_bits(&s->gb, 8);
        break;
    case 1:
        width = get_bits(&s->gb, 16);
        height = get_bits(&s->gb, 16);
        break;
    case 2:
        width = 352;
        height = 288;
        break;
    case 3:
        width = 176;
        height = 144;
        break;
    case 4:
        width = 128;
        height = 96;
        break;
    case 5:
        width = 320;
        height = 240;
        break;
    case 6:
        width = 160;
        height = 120;
        break;
    default:
        width = height = 0;
        break;
    }
    if(av_check_image_size(width, height, 0, s->avctx))
        return -1;
    s->width = width;
    s->height = height;

    s->pict_type = FF_I_TYPE + get_bits(&s->gb, 2);
    s->dropable= s->pict_type > FF_P_TYPE;
    if (s->dropable)
        s->pict_type = FF_P_TYPE;

    skip_bits1(&s->gb); /* deblocking flag */
    s->chroma_qscale= s->qscale = get_bits(&s->gb, 5);

    s->h263_plus = 0;

    s->unrestricted_mv = 1;
    s->h263_long_vectors = 0;

    /* PEI */
    while (get_bits1(&s->gb) != 0) {
        skip_bits(&s->gb, 8);
    }
    s->f_code = 1;

    if(s->avctx->debug & FF_DEBUG_PICT_INFO){
        av_log(s->avctx, AV_LOG_DEBUG, "%c esc_type:%d, qp:%d num:%d\n",
               s->dropable ? 'D' : av_get_pict_type_char(s->pict_type), s->h263_flv-1, s->qscale, s->picture_number);
    }

    s->y_dc_scale_table=
    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;

    return 0;
}

int parse_dts_header(DTSParserContext *pContext, DTSHeader *pHeader, uint8_t *pBuffer, unsigned uSize)
{
  if(!pContext) return -1;
  if(!pHeader) return -1;

  unsigned ExtDescriptor = 0, ExtCoding = 0;

  uint8_t dts_buffer[32 + FF_INPUT_BUFFER_PADDING_SIZE] = {0};
  int ret = ff_dca_convert_bitstream(pBuffer, uSize, dts_buffer, 32);

  bool is16be = (AV_RB32(pBuffer) == DCA_MARKER_RAW_BE);

  /* Parse Core Header */
  if (ret >= 0) {
    pHeader->HasCore = 1;

    GetBitContext *gb = pContext->gb;
    init_get_bits(gb, dts_buffer, 32 << 3);

    skip_bits_long(gb, 32);                             /* Sync code */
    skip_bits1(gb);                                     /* Frame type */
    pHeader->SamplesPerBlock  = get_bits(gb, 5) + 1;    /* Samples deficit */
    pHeader->CRCPresent       = get_bits1(gb);          /* CRC present */
    pHeader->Blocks           = get_bits(gb, 7) + 1;    /* Number of Blocks */
    pHeader->FrameSize        = get_bits(gb, 14) + 1;   /* Primary (core) Frame Size */
    pHeader->ChannelLayout    = get_bits(gb, 6);        /* Channel configuration */
    unsigned sample_index     = get_bits(gb, 4);        /* Sample frequency index */
    pHeader->SampleRate       = avpriv_dca_sample_rates[sample_index];
    unsigned bitrate_index    = get_bits(gb, 5);        /* Bitrate index */
    pHeader->Bitrate          = dca_bit_rates[bitrate_index];
    skip_bits1(gb);                                     /* Down mix */
    skip_bits1(gb);                                     /* Dynamic range */
    skip_bits1(gb);                                     /* Time stamp */
    skip_bits1(gb);                                     /* Auxiliary data */
    skip_bits1(gb);                                     /* HDCD */
    ExtDescriptor             = get_bits(gb, 3);        /* External descriptor  */
    ExtCoding                 = get_bits1(gb);          /* Extended coding */
    skip_bits1(gb);                                     /* ASPF */
    pHeader->LFE              = get_bits(gb, 2);        /* LFE */
    skip_bits1(gb);                                     /* Predictor History */
    if(pHeader->CRCPresent)
      skip_bits(gb, 16);                                /* CRC */
    skip_bits1(gb);                                     /* Multirate Interpolator */
    skip_bits(gb, 4);                                   /* Encoder Software Revision */
    skip_bits(gb, 2);                                   /* Copy history */
    pHeader->ES = get_bits1(gb);                        /* ES */
    skip_bits(gb, 2);                                   /* PCMR (source PCM resolution) */
    skip_bits1(gb);                                     /* SUMF (Front Sum/Difference Flag) */
    skip_bits1(gb);                                     /* SUMS (Surround Sum/Difference Flag) */
    skip_bits(gb, 4);                                   /* Dialog Normalization Parameter or Unspecified (dependent on encoder version) */
  } else {
    pHeader->HasCore = 0;
  }

  if (pHeader->HasCore && !is16be)
    return 0;

  // DTS-HD parsing
  const uint8_t *pHD = NULL;
  if (pHeader->HasCore) { // If we have a core, only search after the normal buffer
    if (uSize > (pHeader->FrameSize + 4)) { // at least 4 bytes extra, could probably insert a minimal size of a HD header, but so what
      pHD = find_marker32_position(pBuffer + pHeader->FrameSize, uSize - pHeader->FrameSize, DCA_HD_MARKER);
    }
  } else {
    pHD = find_marker32_position(pBuffer, uSize, DCA_HD_MARKER);
  }
  if (pHD) {
    pHeader->IsHD = 1;
    size_t remaining = uSize - (pHD - pBuffer);
    parse_dts_hd_header(pContext, pHeader, pHD, (unsigned)remaining);

    const uint8_t *pXChHD = find_marker32_position(pHD, remaining, DCA_XCH_MARKER);
    if (pXChHD) {
      size_t remaining = uSize - (pXChHD - pBuffer);
      parse_dts_xch_hd_header(pContext, pHeader, pXChHD, (unsigned)remaining);
    }

    const uint8_t *pXXChHD = find_marker32_position(pHD, remaining, DCA_XXCH_MARKER);
    if (pXXChHD) {
      size_t remaining = uSize - (pXXChHD - pBuffer);
      parse_dts_xxch_hd_header(pContext, pHeader, pXXChHD, (unsigned)remaining);
    }
  }

  // Handle DTS extensions
  if (ExtCoding) {
    size_t coreSize = pHD ? (pHD - pBuffer) : uSize;
    if (ExtDescriptor == 0 || ExtDescriptor == 3) {
      const uint8_t *pXCh = find_marker32_position(pBuffer, coreSize, DCA_XCH_MARKER);
      if (pXCh) {
        size_t remaining = coreSize - (pXCh - pBuffer);
        parse_dts_xch_header(pContext, pHeader, pXCh, (unsigned)remaining);
      }
    }
    if (ExtDescriptor == 6) {
      const uint8_t *pXXCh = find_marker32_position(pBuffer, coreSize, DCA_XXCH_MARKER);
      if (pXXCh) {
        size_t remaining = coreSize - (pXXCh - pBuffer);
        parse_dts_xxch_header(pContext, pHeader, pXXCh, (unsigned)remaining);
      }
//.........这里部分代码省略.........

/*
    Extract width & height from vol header passed as arg


*/
uint8_t extractMpeg4Info(uint8_t *data,uint32_t dataSize,uint32_t *w,uint32_t *h,uint32_t *time_inc)
{
    // Search startcode
    uint8_t b;
    uint32_t idx=0;
    uint32_t mw,mh;
    uint32_t timeVal;

    //mixDump(data,dataSize);
    //printf("\n");
    while(1)
    {
        uint32_t startcode=0xffffffff;
        while(dataSize>2)
        {
            startcode=(startcode<<8)+data[idx];
            idx++;
            dataSize--;
            if((startcode&0xffffff)==1) break;
        }
        if(dataSize>2)
        {
            //printf("Startcodec:%x\n",data[idx]);
            if((data[idx]&0xF0)==0x20) //VOL start
            {
                dataSize--;
                idx++;
#if 0
                printf("VOL Header:\n");

                if(dataSize<16)
                {
                    mixDump(data+idx,dataSize);
                    printf("\n");
                }
                else
                {
                    mixDump(data+idx,16);
                    printf("\n");
                }
#endif
                // Here we go !
                GetBitContext s;
                init_get_bits( &s,data+idx, dataSize*8);
                //
                skip_bits1(&s); // Random access
                skip_bits(&s,8); // Obj type indication
                if(get_bits(&s,1)) // VO od
                {
                    skip_bits(&s,4); // Ver
                    skip_bits(&s,3);  // Priority
                }
                if(get_bits(&s,4)==15) // custom A/R
                {
                    skip_bits(&s,8);
                    skip_bits(&s,8);
                }
                if(get_bits(&s,1)) // Vol control param
                {
                    skip_bits(&s,2);   //Chroma
                    skip_bits(&s,1);   // Low delay
                    if(get_bits(&s,1)) // VBV Info
                    {
                        skip_bits(&s,16);
                        skip_bits(&s,16);
                        skip_bits(&s,16);
                        skip_bits(&s,15);
                        skip_bits(&s,16);
                    }
                }
                skip_bits(&s,2); //  Shape
                skip_bits(&s,1); //  Marker
                timeVal=get_bits(&s,16); // Time increment
                *time_inc = av_log2(timeVal - 1) + 1;
                if (*time_inc < 1)
                    *time_inc = 1;
                skip_bits(&s,1); //  Marker
                if(get_bits(&s,1)) // Fixed vop rate, compute how much bits needed
                {
                    get_bits(&s, *time_inc);
                }
                skip_bits(&s,1); //  Marker
                mw=get_bits(&s,13);
                skip_bits(&s,1); //  Marker
                mh=get_bits(&s,13);
                // /Here we go
                //printf("%d x %d \n",mw,mh);
                *h=mh;
                *w=mw;
                return 1;;
                // Free get bits ?
                // WTF ?
            }
            continue;
        }
//.........这里部分代码省略.........

/**
 * Decode the H.261 picture header.
 * @return <0 if no startcode found
 */
static int h261_decode_picture_header(H261Context *h)
{
    MpegEncContext *const s = &h->s;
    int format, i;
    uint32_t startcode = 0;

    for (i = get_bits_left(&s->gb); i > 24; i -= 1) {
        startcode = ((startcode << 1) | get_bits(&s->gb, 1)) & 0x000FFFFF;

        if (startcode == 0x10)
            break;
    }

    if (startcode != 0x10) {
        av_log(s->avctx, AV_LOG_ERROR, "Bad picture start code\n");
        return -1;
    }

    /* temporal reference */
    i = get_bits(&s->gb, 5); /* picture timestamp */
    if (i < (s->picture_number & 31))
        i += 32;
    s->picture_number = (s->picture_number & ~31) + i;

#ifdef IDE_COMPILE
	s->avctx->time_base.num = 1001;
	s->avctx->time_base.den = 30000;
#else
	s->avctx->time_base      = (AVRational) { 1001, 30000 };
#endif

    /* PTYPE starts here */
    skip_bits1(&s->gb); /* split screen off */
    skip_bits1(&s->gb); /* camera  off */
    skip_bits1(&s->gb); /* freeze picture release off */

    format = get_bits1(&s->gb);

    // only 2 formats possible
    if (format == 0) { // QCIF
        s->width     = 176;
        s->height    = 144;
        s->mb_width  = 11;
        s->mb_height = 9;
    } else { // CIF
        s->width     = 352;
        s->height    = 288;
        s->mb_width  = 22;
        s->mb_height = 18;
    }

    s->mb_num = s->mb_width * s->mb_height;

    skip_bits1(&s->gb); /* still image mode off */
    skip_bits1(&s->gb); /* Reserved */

    /* PEI */
    if (skip_1stop_8data_bits(&s->gb) < 0)
        return AVERROR_INVALIDDATA;

    /* H.261 has no I-frames, but if we pass AV_PICTURE_TYPE_I for the first
     * frame, the codec crashes if it does not contain all I-blocks
     * (e.g. when a packet is lost). */
    s->pict_type = AV_PICTURE_TYPE_P;

    h->gob_number = 0;
    return 0;
}

/**
 * Decode Smacker audio data
 */
static int smka_decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    GetBitContext gb;
    HuffContext h[4];
    VLC vlc[4];
    int16_t *samples = data;
    uint8_t *samples8 = data;
    int val;
    int i, res;
    int unp_size;
    int bits, stereo;
    int pred[2] = {0, 0};

    if (buf_size <= 4) {
        av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
        return AVERROR(EINVAL);
    }

    unp_size = AV_RL32(buf);

    init_get_bits(&gb, buf + 4, (buf_size - 4) * 8);

    if(!get_bits1(&gb)){
        av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
        *data_size = 0;
        return 1;
    }
    stereo = get_bits1(&gb);
    bits = get_bits1(&gb);
    if (unp_size & 0xC0000000 || unp_size > *data_size) {
        av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n");
        return -1;
    }
    if (stereo ^ (avctx->channels != 1)) {
        av_log(avctx, AV_LOG_ERROR, "channels mismatch\n");
        return AVERROR(EINVAL);
    }
    if (bits && avctx->sample_fmt == AV_SAMPLE_FMT_U8) {
        av_log(avctx, AV_LOG_ERROR, "sample format mismatch\n");
        return AVERROR(EINVAL);
    }

    memset(vlc, 0, sizeof(VLC) * 4);
    memset(h, 0, sizeof(HuffContext) * 4);
    // Initialize
    for(i = 0; i < (1 << (bits + stereo)); i++) {
        h[i].length = 256;
        h[i].maxlength = 0;
        h[i].current = 0;
        h[i].bits = av_mallocz(256 * 4);
        h[i].lengths = av_mallocz(256 * sizeof(int));
        h[i].values = av_mallocz(256 * sizeof(int));
        skip_bits1(&gb);
        smacker_decode_tree(&gb, &h[i], 0, 0);
        skip_bits1(&gb);
        if(h[i].current > 1) {
            res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
                    h[i].lengths, sizeof(int), sizeof(int),
                    h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
            if(res < 0) {
                av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
                return -1;
            }
        }
    }
    if(bits) { //decode 16-bit data
        for(i = stereo; i >= 0; i--)
            pred[i] = av_bswap16(get_bits(&gb, 16));
        for(i = 0; i <= stereo; i++)
            *samples++ = pred[i];
        for(; i < unp_size / 2; i++) {
            if(i & stereo) {
                if(vlc[2].table)
                    res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val  = h[2].values[res];
                if(vlc[3].table)
                    res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val |= h[3].values[res] << 8;
                pred[1] += sign_extend(val, 16);
                *samples++ = av_clip_int16(pred[1]);
            } else {
                if(vlc[0].table)
                    res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val  = h[0].values[res];
                if(vlc[1].table)
                    res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
                else
                    res = 0;
                val |= h[1].values[res] << 8;
//.........这里部分代码省略.........

static AVPictureType parse_picture_type(const uint8_t *buf, int buflen, CVC1HeaderParser *vc1Header)
{
  AVPictureType pictype = AV_PICTURE_TYPE_NONE;
  int skipped = 0;
  const BYTE *framestart = buf;
  if (IS_MARKER(AV_RB32(buf))) {
    framestart = NULL;
    const BYTE *start, *end, *next;
    next = buf;
    for (start = buf, end = buf + buflen; next < end; start = next) {
      if (AV_RB32(start) == VC1_CODE_FRAME) {
        framestart = start + 4;
        break;
      }
      next = find_next_marker(start + 4, end);
    }
  }
  if (framestart) {
    GetBitContext gb;
    init_get_bits(&gb, framestart, (buflen - (framestart-buf))*8);
    if (vc1Header->hdr.profile == PROFILE_ADVANCED) {
      int fcm = PROGRESSIVE;
      if (vc1Header->hdr.interlaced)
        fcm = decode012(&gb);
      if (fcm == ILACE_FIELD) {
        int fptype = get_bits(&gb, 3);
        pictype = (fptype & 2) ? AV_PICTURE_TYPE_P : AV_PICTURE_TYPE_I;
        if (fptype & 4) // B-picture
          pictype = (fptype & 2) ? AV_PICTURE_TYPE_BI : AV_PICTURE_TYPE_B;
      } else {
        switch (get_unary(&gb, 0, 4)) {
        case 0:
            pictype = AV_PICTURE_TYPE_P;
            break;
        case 1:
            pictype = AV_PICTURE_TYPE_B;
            break;
        case 2:
            pictype = AV_PICTURE_TYPE_I;
            break;
        case 3:
            pictype = AV_PICTURE_TYPE_BI;
            break;
        case 4:
            pictype = AV_PICTURE_TYPE_P; // skipped pic
            skipped = 1;
            break;
        }
      }
    } else {
      if (vc1Header->hdr.finterp)
        skip_bits1(&gb);
      skip_bits(&gb, 2); // framecnt
      if (vc1Header->hdr.rangered)
        skip_bits1(&gb);
      int pic = get_bits1(&gb);
      if (vc1Header->hdr.bframes) {
        if (!pic) {
          if (get_bits1(&gb)) {
            pictype = AV_PICTURE_TYPE_I;
          } else {
            pictype = AV_PICTURE_TYPE_B;
          }
        } else {
          pictype = AV_PICTURE_TYPE_P;
        }
      } else {
        pictype = pic ? AV_PICTURE_TYPE_P : AV_PICTURE_TYPE_I;
      }
    }
  }
  return pictype;
}

void CVC1HeaderParser::VC1ParseSequenceHeader(GetBitContext *gb)
{
  hdr.profile = get_bits(gb, 2);

  if (hdr.profile == PROFILE_ADVANCED) {
    hdr.valid = 1;

    hdr.level = get_bits(gb, 3);
    skip_bits(gb, 2); // Chroma Format, only 1 should be set for 4:2:0
    skip_bits(gb, 3); // frmrtq_postproc
    skip_bits(gb, 5); // bitrtq_postproc
    skip_bits1(gb);   // postprocflag

    hdr.width = (get_bits(gb, 12) + 1) << 1;
    hdr.height = (get_bits(gb, 12) + 1) << 1;

    hdr.broadcast = get_bits1(gb);    // broadcast
    hdr.interlaced = get_bits1(gb);   // interlaced

    skip_bits1(gb); // tfcntrflag
    skip_bits1(gb); // finterpflag
    skip_bits1(gb); // reserved
    skip_bits1(gb); // psf

    if (get_bits1(gb)) { // Display Info
      int w, h, ar = 0;
      w = get_bits(gb, 14) + 1;
      h = get_bits(gb, 14) + 1;
      if (get_bits1(gb))
        ar = get_bits(gb, 4);
      if (ar && ar < 14) {
        hdr.ar = ff_vc1_pixel_aspect[ar];
      } else if (ar == 15) {
        w = get_bits(gb, 8) + 1;
        h = get_bits(gb, 8) + 1;
        hdr.ar.num = w;
        hdr.ar.den = h;
      } else {
        av_reduce(&hdr.ar.num, &hdr.ar.den, hdr.height * w, hdr.width * h, 1 << 30);
      }
    }

    // TODO: add other fields
  } else {
    hdr.valid = 1;
    hdr.old_interlaced = get_bits1(gb); // res_y411
    skip_bits1(gb); // res_sprite

    skip_bits(gb, 3); // frmrtq_postproc
    skip_bits(gb, 5); // bitrtq_postproc
    skip_bits1(gb);   // loop_filter
    skip_bits1(gb);   // res_x8
    skip_bits1(gb);   // multires
    skip_bits1(gb);   // rest_fasttx
    skip_bits1(gb);   // fastuvmc
    skip_bits1(gb);   // extended_mv
    skip_bits(gb, 2); // dquant
    skip_bits1(gb);   // vstransform
    skip_bits1(gb);   // res_transtab
    skip_bits1(gb);   // overlap
    skip_bits1(gb);   // resync marker
    hdr.rangered = get_bits1(gb);
    hdr.bframes = get_bits(gb, 3);
    skip_bits(gb, 2); // quant mode
    hdr.finterp = get_bits1(gb);
  }
}

/**
 * read the next MVs for OBMC. yes this is a ugly hack, feel free to send a patch :)
 */
static void preview_obmc(MpegEncContext *s){
    GetBitContext gb= s->gb;

    int cbpc, i, pred_x, pred_y, mx, my;
    int16_t *mot_val;
    const int xy= s->mb_x + 1 + s->mb_y * s->mb_stride;
    const int stride= s->b8_stride*2;

    for(i=0; i<4; i++)
        s->block_index[i]+= 2;
    for(i=4; i<6; i++)
        s->block_index[i]+= 1;
    s->mb_x++;

    av_assert2(s->pict_type == AV_PICTURE_TYPE_P);

    do{
        if (get_bits1(&s->gb)) {
            /* skip mb */
            mot_val = s->current_picture.motion_val[0][s->block_index[0]];
            mot_val[0       ]= mot_val[2       ]=
            mot_val[0+stride]= mot_val[2+stride]= 0;
            mot_val[1       ]= mot_val[3       ]=
            mot_val[1+stride]= mot_val[3+stride]= 0;

            s->current_picture.mb_type[xy] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_L0;
            goto end;
        }
        cbpc = get_vlc2(&s->gb, ff_h263_inter_MCBPC_vlc.table, INTER_MCBPC_VLC_BITS, 2);
    }while(cbpc == 20);

    if(cbpc & 4){
        s->current_picture.mb_type[xy] = MB_TYPE_INTRA;
    }else{
        get_vlc2(&s->gb, ff_h263_cbpy_vlc.table, CBPY_VLC_BITS, 1);
        if (cbpc & 8) {
            if(s->modified_quant){
                if(get_bits1(&s->gb)) skip_bits(&s->gb, 1);
                else                  skip_bits(&s->gb, 5);
            }else
                skip_bits(&s->gb, 2);
        }

        if ((cbpc & 16) == 0) {
                s->current_picture.mb_type[xy] = MB_TYPE_16x16 | MB_TYPE_L0;
                /* 16x16 motion prediction */
                mot_val= ff_h263_pred_motion(s, 0, 0, &pred_x, &pred_y);
                if (s->umvplus)
                   mx = h263p_decode_umotion(s, pred_x);
                else
                   mx = ff_h263_decode_motion(s, pred_x, 1);

                if (s->umvplus)
                   my = h263p_decode_umotion(s, pred_y);
                else
                   my = ff_h263_decode_motion(s, pred_y, 1);

                mot_val[0       ]= mot_val[2       ]=
                mot_val[0+stride]= mot_val[2+stride]= mx;
                mot_val[1       ]= mot_val[3       ]=
                mot_val[1+stride]= mot_val[3+stride]= my;
        } else {
            s->current_picture.mb_type[xy] = MB_TYPE_8x8 | MB_TYPE_L0;
            for(i=0;i<4;i++) {
                mot_val = ff_h263_pred_motion(s, i, 0, &pred_x, &pred_y);
                if (s->umvplus)
                  mx = h263p_decode_umotion(s, pred_x);
                else
                  mx = ff_h263_decode_motion(s, pred_x, 1);

                if (s->umvplus)
                  my = h263p_decode_umotion(s, pred_y);
                else
                  my = ff_h263_decode_motion(s, pred_y, 1);
                if (s->umvplus && (mx - pred_x) == 1 && (my - pred_y) == 1)
                  skip_bits1(&s->gb); /* Bit stuffing to prevent PSC */
                mot_val[0] = mx;
                mot_val[1] = my;
            }
        }
    }
end:

    for(i=0; i<4; i++)
        s->block_index[i]-= 2;
    for(i=4; i<6; i++)
        s->block_index[i]-= 1;
    s->mb_x--;

    s->gb= gb;
}