vp3.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

            } else {
                s->superblock_macroblocks[mapping_index] = -1;
                debug_init("    superblock %d, position %d has no macroblock (%d/%d x %d/%d)\n",
                    i, j,
                    current_width, right_edge, current_height, bottom_edge);
            }

            mapping_index++;
        }
    }

    /* initialize the macroblock <-> fragment mapping */
    current_fragment = 0;
    current_macroblock = 0;
    mapping_index = 0;
    for (i = 0; i < s->fragment_height; i += 2) {

        for (j = 0; j < s->fragment_width; j += 2) {

            debug_init("    macroblock %d contains fragments: ", current_macroblock);
            s->all_fragments[current_fragment].macroblock = current_macroblock;
            s->macroblock_fragments[mapping_index++] = current_fragment;
            debug_init("%d ", current_fragment);

            if (j + 1 < s->fragment_width) {
                s->all_fragments[current_fragment + 1].macroblock = current_macroblock;
                s->macroblock_fragments[mapping_index++] = current_fragment + 1;
                debug_init("%d ", current_fragment + 1);
            } else
                s->macroblock_fragments[mapping_index++] = -1;

            if (i + 1 < s->fragment_height) {
                s->all_fragments[current_fragment + s->fragment_width].macroblock = 
                    current_macroblock;
                s->macroblock_fragments[mapping_index++] = 
                    current_fragment + s->fragment_width;
                debug_init("%d ", current_fragment + s->fragment_width);
            } else
                s->macroblock_fragments[mapping_index++] = -1;

            if ((j + 1 < s->fragment_width) && (i + 1 < s->fragment_height)) {
                s->all_fragments[current_fragment + s->fragment_width + 1].macroblock = 
                    current_macroblock;
                s->macroblock_fragments[mapping_index++] = 
                    current_fragment + s->fragment_width + 1;
                debug_init("%d ", current_fragment + s->fragment_width + 1);
            } else
                s->macroblock_fragments[mapping_index++] = -1;

            /* C planes */
            c_fragment = s->u_fragment_start + 
                (i * s->fragment_width / 4) + (j / 2);
            s->all_fragments[c_fragment].macroblock = s->macroblock_count;
            s->macroblock_fragments[mapping_index++] = c_fragment;
            debug_init("%d ", c_fragment);

            c_fragment = s->v_fragment_start + 
                (i * s->fragment_width / 4) + (j / 2);
            s->all_fragments[c_fragment].macroblock = s->macroblock_count;
            s->macroblock_fragments[mapping_index++] = c_fragment;
            debug_init("%d ", c_fragment);

            debug_init("\n");

            if (j + 2 <= s->fragment_width)
                current_fragment += 2;
            else 
                current_fragment++;
            current_macroblock++;
        }

        current_fragment += s->fragment_width;
    }

    return 0;  /* successful path out */
}

/*
 * This function unpacks a single token (which should be in the range 0..31)
 * and returns a zero run (number of zero coefficients in current DCT matrix
 * before next non-zero coefficient), the next DCT coefficient, and the
 * number of consecutive, non-EOB'd DCT blocks to EOB.
 */
static void unpack_token(GetBitContext *gb, int token, int *zero_run,
                         DCTELEM *coeff, int *eob_run) 
{
    int sign;

    *zero_run = 0;
    *eob_run = 0;
    *coeff = 0;

    debug_token("    vp3 token %d: ", token);
    switch (token) {

    case 0:
        debug_token("DCT_EOB_TOKEN, EOB next block\n");
        *eob_run = 1;
        break;

    case 1:
        debug_token("DCT_EOB_PAIR_TOKEN, EOB next 2 blocks\n");
        *eob_run = 2;
        break;

    case 2:
        debug_token("DCT_EOB_TRIPLE_TOKEN, EOB next 3 blocks\n");
        *eob_run = 3;
        break;

    case 3:
        debug_token("DCT_REPEAT_RUN_TOKEN, ");
        *eob_run = get_bits(gb, 2) + 4;
        debug_token("EOB the next %d blocks\n", *eob_run);
        break;

    case 4:
        debug_token("DCT_REPEAT_RUN2_TOKEN, ");
        *eob_run = get_bits(gb, 3) + 8;
        debug_token("EOB the next %d blocks\n", *eob_run);
        break;

    case 5:
        debug_token("DCT_REPEAT_RUN3_TOKEN, ");
        *eob_run = get_bits(gb, 4) + 16;
        debug_token("EOB the next %d blocks\n", *eob_run);
        break;

    case 6:
        debug_token("DCT_REPEAT_RUN4_TOKEN, ");
        *eob_run = get_bits(gb, 12);
        debug_token("EOB the next %d blocks\n", *eob_run);
        break;

    case 7:
        debug_token("DCT_SHORT_ZRL_TOKEN, ");
        /* note that this token actually indicates that (3 extra bits) + 1 0s
         * should be output; this case specifies a run of (3 EBs) 0s and a
         * coefficient of 0. */
        *zero_run = get_bits(gb, 3);
        *coeff = 0;
        debug_token("skip the next %d positions in output matrix\n", *zero_run + 1);
        break;

    case 8:
        debug_token("DCT_ZRL_TOKEN, ");
        /* note that this token actually indicates that (6 extra bits) + 1 0s
         * should be output; this case specifies a run of (6 EBs) 0s and a
         * coefficient of 0. */
        *zero_run = get_bits(gb, 6);
        *coeff = 0;
        debug_token("skip the next %d positions in output matrix\n", *zero_run + 1);
        break;

    case 9:
        debug_token("ONE_TOKEN, output 1\n");
        *coeff = 1;
        break;

    case 10:
        debug_token("MINUS_ONE_TOKEN, output -1\n");
        *coeff = -1;
        break;

    case 11:
        debug_token("TWO_TOKEN, output 2\n");
        *coeff = 2;
        break;

    case 12:
        debug_token("MINUS_TWO_TOKEN, output -2\n");
        *coeff = -2;
        break;

    case 13:
    case 14:
    case 15:
    case 16:
        debug_token("LOW_VAL_TOKENS, ");
        if (get_bits(gb, 1))
            *coeff = -(3 + (token - 13));
        else
            *coeff = 3 + (token - 13);
        debug_token("output %d\n", *coeff);
        break;

    case 17:
        debug_token("DCT_VAL_CATEGORY3, ");
        sign = get_bits(gb, 1);
        *coeff = 7 + get_bits(gb, 1);
        if (sign)
            *coeff = -(*coeff);
        debug_token("output %d\n", *coeff);
        break;

    case 18:
        debug_token("DCT_VAL_CATEGORY4, ");
        sign = get_bits(gb, 1);
        *coeff = 9 + get_bits(gb, 2);
        if (sign)
            *coeff = -(*coeff);
        debug_token("output %d\n", *coeff);
        break;

    case 19:
        debug_token("DCT_VAL_CATEGORY5, ");
        sign = get_bits(gb, 1);
        *coeff = 13 + get_bits(gb, 3);
        if (sign)
            *coeff = -(*coeff);
        debug_token("output %d\n", *coeff);
        break;

    case 20:
        debug_token("DCT_VAL_CATEGORY6, ");
        sign = get_bits(gb, 1);
        *coeff = 21 + get_bits(gb, 4);
        if (sign)
            *coeff = -(*coeff);
        debug_token("output %d\n", *coeff);
        break;

    case 21:
        debug_token("DCT_VAL_CATEGORY7, ");
        sign = get_bits(gb, 1);
        *coeff = 37 + get_bits(gb, 5);
        if (sign)
            *coeff = -(*coeff);
        debug_token("output %d\n", *coeff);
        break;

    case 22:
        debug_token("DCT_VAL_CATEGORY8, ");
        sign = get_bits(gb, 1);
        *coeff = 69 + get_bits(gb, 9);
        if (sign)
            *coeff = -(*coeff);
        debug_token("output %d\n", *coeff);
        break;

    case 23:
    case 24:
    case 25:
    case 26:
    case 27:
        debug_token("DCT_RUN_CATEGORY1, ");
        *zero_run = token - 22;
        if (get_bits(gb, 1))
            *coeff = -1;
        else
            *coeff = 1;
        debug_token("output %d 0s, then %d\n", *zero_run, *coeff);
        break;

    case 28:
        debug_token("DCT_RUN_CATEGORY1B, ");
        if (get_bits(gb, 1))
            *coeff = -1;
        else
            *coeff = 1;
        *zero_run = 6 + get_bits(gb, 2);
        debug_token("output %d 0s, then %d\n", *zero_run, *coeff);
        break;

    case 29:
        debug_token("DCT_RUN_CATEGORY1C, ");
        if (get_bits(gb, 1))
            *coeff = -1;
        else
            *coeff = 1;
        *zero_run = 10 + get_bits(gb, 3);
        debug_token("output %d 0s, then %d\n", *zero_run, *coeff);
        break;

    case 30:
        debug_token("DCT_RUN_CATEGORY2, ");
        sign = get_bits(gb, 1);
        *coeff = 2 + get_bits(gb, 1);
        if (sign)
            *coeff = -(*coeff);
        *zero_run = 1;
        debug_token("output %d 0s, then %d\n", *zero_run, *coeff);
        break;

    case 31:
        debug_token("DCT_RUN_CATEGORY2, ");
        sign = get_bits(gb, 1);
        *coeff = 2 + get_bits(gb, 1);
        if (sign)
            *coeff = -(*coeff);
        *zero_run = 2 + get_bits(gb, 1);
        debug_token("output %d 0s, then %d\n", *zero_run, *coeff);
        break;

    default:
        av_log(NULL, AV_LOG_ERROR, "  vp3: help! Got a bad token: %d > 31\n", token);
        break;

  }
}

/*
 * This function wipes out all of the fragment data.
 */
static void init_frame(Vp3DecodeContext *s, GetBitContext *gb)
{
    int i;

    /* zero out all of the fragment information */
    s->coded_fragment_list_index = 0;
    for (i = 0; i < s->fragment_count; i++) {
        memset(s->all_fragments[i].coeffs, 0, 64 * sizeof(DCTELEM));
        s->all_fragments[i].coeff_count = 0;
        s->all_fragments[i].last_coeff = 0;
s->all_fragments[i].motion_x = 0xbeef;
s->all_fragments[i].motion_y = 0xbeef;
    }
}

/*
 * This function sets of the dequantization tables used for a particular
 * frame.
 */
static void init_dequantizer(Vp3DecodeContext *s)
{

    int quality_scale = s->coded_quality_threshold[s->quality_index];
    int dc_scale_factor = s->coded_dc_scale_factor[s->quality_index];
    int i, j;

    debug_vp3("  vp3: initializing dequantization tables\n");

    /* 
     * Scale dequantizers:
     *
     *   quantizer * sf
     *   --------------
     *        100
     *
     * where sf = dc_scale_factor for DC quantizer
     *           or quality_scale for AC quantizer
     *
     * Then, saturate the result to a lower limit of MIN_DEQUANT_VAL.
     */
#define SCALER 4

    /* scale DC quantizers */
    s->intra_y_dequant[0] = s->coded_intra_y_dequant[0] * dc_scale_factor / 100;
    if (s->intra_y_dequant[0] < MIN_DEQUANT_VAL * 2)
        s->intra_y_dequant[0] = MIN_DEQUANT_VAL * 2;
    s->intra_y_dequant[0] *= SCALER;

    s->intra_c_dequant[0] = s->coded_intra_c_dequant[0] * dc_scale_factor / 100;
    if (s->intra_c_dequant[0] < MIN_DEQUANT_VAL * 2)
        s->intra_c_dequant[0] = MIN_DEQUANT_VAL * 2;
    s->intra_c_dequant[0] *= SCALER;

    s->inter_dequant[0] = s->coded_inter_dequant[0] * dc_scale_factor / 100;
    if (s->inter_dequant[0] < MIN_DEQUANT_VAL * 4)
        s->inter_dequant[0] = MIN_DEQUANT_VAL * 4;
    s->inter_dequant[0] *= SCALER;

    /* scale AC quantizers, zigzag at the same time in preparation for
     * the dequantization phase */
    for (i = 1; i < 64; i++) {

        j = zigzag_index[i];

        s->intra_y_dequant[j] = s->coded_intra_y_dequant[i] * quality_scale / 100;
        if (s->intra_y_dequant[j] < MIN_DEQUANT_VAL)
            s->intra_y_dequant[j] = MIN_DEQUANT_VAL;
        s->intra_y_dequant[j] *= SCALER;

        s->intra_c_dequant[j] = s->coded_intra_c_dequant[i] * quality_scale / 100;
        if (s->intra_c_dequant[j] < MIN_DEQUANT_VAL)
            s->intra_c_dequant[j] = MIN_DEQUANT_VAL;
        s->intra_c_dequant[j] *= SCALER;

        s->inter_dequant[j] = s->coded_inter_dequant[i] * quality_scale / 100;
        if (s->inter_dequant[j] < MIN_DEQUANT_VAL * 2)
            s->inter_dequant[j] = MIN_DEQUANT_VAL * 2;
        s->inter_dequant[j] *= SCALER;
    }
    
    memset(s->qscale_table, (FFMAX(s->intra_y_dequant[1], s->intra_c_dequant[1])+8)/16, 512); //FIXME finetune

    /* print debug information as requested */
    debug_dequantizers("intra Y dequantizers:\n");
    for (i = 0; i < 8; i++) {
      for (j = i * 8; j < i * 8 + 8; j++) {
        debug_dequantizers(" %4d,", s->intra_y_dequant[j]);
      }
      debug_dequantizers("\n");
    }
    debug_dequantizers("\n");

    debug_dequantizers("intra C dequantizers:\n");
    for (i = 0; i < 8; i++) {
      for (j = i * 8; j < i * 8 + 8; j++) {
        debug_dequantizers(" %4d,", s->intra_c_dequant[j]);
      }
      debug_dequantizers("\n");
    }
    debug_dequantizers("\n");

    debug_dequantizers("interframe dequantizers:\n");
    for (i = 0; i < 8; i++) {
      for (j = i * 8; j < i * 8 + 8; j++) {