rvlc.c

WINCE mp4 format source

    int16_t is_position = 0;
    int16_t noise_energy = ics->rev_global_gain;

#ifdef PRINT_RVLC
    printf("\nrev_global_gain: %d\n", ics->rev_global_gain);
#endif

    if (intensity_used)
    {
        is_position = rvlc_huffman_sf(ld_sf, ld_esc, -1);
#ifdef PRINT_RVLC
        printf("is_position: %d\n", is_position);
#endif
    }

    for (g = ics->num_window_groups-1; g >= 0; g--)
    {
        for (sfb = ics->max_sfb-1; sfb >= 0; sfb--)
        {
            if (error)
            {
                ics->scale_factors[g][sfb] = 0;
            } else {
                switch (ics->sfb_cb[g][sfb])
                {
                case ZERO_HCB: /* zero book */
                    ics->scale_factors[g][sfb] = 0;
                    break;
                case INTENSITY_HCB: /* intensity books */
                case INTENSITY_HCB2:

                    if (is_pcm_flag)
                    {
                        is_pcm_flag = 0;
                        ics->scale_factors[g][sfb] = is_position;
                    } else {
                        t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
                        is_position -= t;

                        ics->scale_factors[g][sfb] = (uint8_t)is_position;
                    }
                    break;
                case NOISE_HCB: /* noise books */

                    /* decode noise energy */
                    if (noise_pcm_flag)
                    {
                        noise_pcm_flag = 0;
                        noise_energy = ics->dpcm_noise_last_position;
                    } else {
                        t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
                        noise_energy -= t;
                    }

                    ics->scale_factors[g][sfb] = (uint8_t)noise_energy;
                    break;
                default: /* spectral books */

                    if (sf_pcm_flag || (sfb == 0))
                    {
                        sf_pcm_flag = 0;
                        if (sfb == 0)
                            scale_factor = ics->global_gain;
                    } else {
                        /* decode scale factor */
                        t = rvlc_huffman_sf(ld_sf, ld_esc, -1);
                        scale_factor -= t;
                    }

                    if (scale_factor < 0)
                        return 4;

                    ics->scale_factors[g][sfb] = (uint8_t)scale_factor;
                    break;
                }
#ifdef PRINT_RVLC
                printf("%3d:%4d%4d\n", sfb, ics->sfb_cb[g][sfb],
                    ics->scale_factors[g][sfb]);
#endif
                if (t == 99)
                {
                    error = 1;
                }
            }
        }
    }

#ifdef PRINT_RVLC
    printf("\n\n");
#endif

    return 0;
}
#endif

/* index == 99 means not allowed codeword */
static rvlc_huff_table book_rvlc[] = {
    /*index  length  codeword */
    {  0, 1,   0 }, /*         0 */
    { -1, 3,   5 }, /*       101 */
    {  1, 3,   7 }, /*       111 */
    { -2, 4,   9 }, /*      1001 */
    { -3, 5,  17 }, /*     10001 */
    {  2, 5,  27 }, /*     11011 */
    { -4, 6,  33 }, /*    100001 */
    { 99, 6,  50 }, /*    110010 */
    {  3, 6,  51 }, /*    110011 */
    { 99, 6,  52 }, /*    110100 */
    { -7, 7,  65 }, /*   1000001 */
    { 99, 7,  96 }, /*   1100000 */
    { 99, 7,  98 }, /*   1100010 */
    {  7, 7,  99 }, /*   1100011 */
    {  4, 7, 107 }, /*   1101011 */
    { -5, 8, 129 }, /*  10000001 */
    { 99, 8, 194 }, /*  11000010 */
    {  5, 8, 195 }, /*  11000011 */
    { 99, 8, 212 }, /*  11010100 */
    { 99, 9, 256 }, /* 100000000 */
    { -6, 9, 257 }, /* 100000001 */
    { 99, 9, 426 }, /* 110101010 */
    {  6, 9, 427 }, /* 110101011 */
    { 99, 10,  0 } /* Shouldn't come this far */
};

static rvlc_huff_table book_escape[] = {
    /*index  length  codeword */
    { 1, 2, 0 },
    { 0, 2, 2 },
    { 3, 3, 2 },
    { 2, 3, 6 },
    { 4, 4, 14 },
    { 7, 5, 13 },
    { 6, 5, 15 },
    { 5, 5, 31 },
    { 11, 6, 24 },
    { 10, 6, 25 },
    { 9, 6, 29 },
    { 8, 6, 61 },
    { 13, 7, 56  },
    { 12, 7, 120 },
    { 15, 8, 114 },
    { 14, 8, 242 },
    { 17, 9, 230 },
    { 16, 9, 486 },
    { 19, 10, 463  },
    { 18, 10, 974  },
    { 22, 11, 925  },
    { 20, 11, 1950 },
    { 21, 11, 1951 },
    { 23, 12, 1848 },
    { 25, 13, 3698 },
    { 24, 14, 7399 },
    { 26, 15, 14797 },
    { 49, 19, 236736 },
    { 50, 19, 236737 },
    { 51, 19, 236738 },
    { 52, 19, 236739 },
    { 53, 19, 236740 },
    { 27, 20, 473482 },
    { 28, 20, 473483 },
    { 29, 20, 473484 },
    { 30, 20, 473485 },
    { 31, 20, 473486 },
    { 32, 20, 473487 },
    { 33, 20, 473488 },
    { 34, 20, 473489 },
    { 35, 20, 473490 },
    { 36, 20, 473491 },
    { 37, 20, 473492 },
    { 38, 20, 473493 },
    { 39, 20, 473494 },
    { 40, 20, 473495 },
    { 41, 20, 473496 },
    { 42, 20, 473497 },
    { 43, 20, 473498 },
    { 44, 20, 473499 },
    { 45, 20, 473500 },
    { 46, 20, 473501 },
    { 47, 20, 473502 },
    { 48, 20, 473503 },
    { 99, 21,  0 } /* Shouldn't come this far */
};

static int8_t rvlc_huffman_sf(bitfile *ld_sf, bitfile *ld_esc,
                              int8_t direction)
{
    uint8_t i, j;
    int8_t index;
    uint32_t cw;
    rvlc_huff_table *h = book_rvlc;
    
    i = h->len;
    if (direction > 0)
        cw = faad_getbits(ld_sf, i DEBUGVAR(1,0,""));
    else
        cw = faad_getbits_rev(ld_sf, i DEBUGVAR(1,0,""));

    while ((cw != h->cw)
        && (i < 10))
    {
        h++;
        j = h->len-i;
        i += j;
        cw <<= j;
        if (direction > 0)
            cw |= faad_getbits(ld_sf, j DEBUGVAR(1,0,""));
        else
            cw |= faad_getbits_rev(ld_sf, j DEBUGVAR(1,0,""));
    }

    index = h->index;

    if (index == +ESC_VAL)
    {
        int8_t esc = rvlc_huffman_esc(ld_esc, direction);
        if (esc == 99)
            return 99;
        index += esc;
#ifdef PRINT_RVLC
        printf("esc: %d - ", esc);
#endif
    }
    if (index == -ESC_VAL)
    {
        int8_t esc = rvlc_huffman_esc(ld_esc, direction);
        if (esc == 99)
            return 99;
        index -= esc;
#ifdef PRINT_RVLC
        printf("esc: %d - ", esc);
#endif
    }

    return index;
}

static int8_t rvlc_huffman_esc(bitfile *ld,
                               int8_t direction)
{
    uint8_t i, j;
    uint32_t cw;
    rvlc_huff_table *h = book_escape;

    i = h->len;
    if (direction > 0)
        cw = faad_getbits(ld, i DEBUGVAR(1,0,""));
    else
        cw = faad_getbits_rev(ld, i DEBUGVAR(1,0,""));

    while ((cw != h->cw)
        && (i < 21))
    {
        h++;
        j = h->len-i;
        i += j;
        cw <<= j;
        if (direction > 0)
            cw |= faad_getbits(ld, j DEBUGVAR(1,0,""));
        else
            cw |= faad_getbits_rev(ld, j DEBUGVAR(1,0,""));
    }

    return h->index;
}

#endif