sbr_syntax.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

#endif

            tmp_nr_bits += sbr_extension(ld, sbr, sbr->bs_extension_id, nr_bits_left);

            /* check if the data read is bigger than the number of available bits */
            if (tmp_nr_bits > nr_bits_left)
                return 1;

            nr_bits_left -= tmp_nr_bits;
        }

        /* Corrigendum */
        if (nr_bits_left > 0)
        {
            faad_getbits(ld, nr_bits_left
                DEBUGVAR(1,280,"sbr_single_channel_element(): nr_bits_left"));
        }
    }

    return 0;
}

/* table 6 */
static uint8_t sbr_channel_pair_element(bitfile *ld, sbr_info *sbr)
{
    uint8_t n, result;

    if (faad_get1bit(ld
        DEBUGVAR(1,228,"sbr_single_channel_element(): bs_data_extra")))
    {
        faad_getbits(ld, 4
            DEBUGVAR(1,228,"sbr_channel_pair_element(): bs_reserved_bits_data"));
        faad_getbits(ld, 4
            DEBUGVAR(1,228,"sbr_channel_pair_element(): bs_reserved_bits_data"));
    }

    sbr->bs_coupling = faad_get1bit(ld
        DEBUGVAR(1,228,"sbr_channel_pair_element(): bs_coupling"));

    if (sbr->bs_coupling)
    {
        if ((result = sbr_grid(ld, sbr, 0)) > 0)
            return result;

        /* need to copy some data from left to right */
        sbr->bs_frame_class[1] = sbr->bs_frame_class[0];
        sbr->L_E[1] = sbr->L_E[0];
        sbr->L_Q[1] = sbr->L_Q[0];
        sbr->bs_pointer[1] = sbr->bs_pointer[0];

        for (n = 0; n <= sbr->L_E[0]; n++)
        {
            sbr->t_E[1][n] = sbr->t_E[0][n];
            sbr->f[1][n] = sbr->f[0][n];
        }
        for (n = 0; n <= sbr->L_Q[0]; n++)
            sbr->t_Q[1][n] = sbr->t_Q[0][n];

        sbr_dtdf(ld, sbr, 0);
        sbr_dtdf(ld, sbr, 1);
        invf_mode(ld, sbr, 0);

        /* more copying */
        for (n = 0; n < sbr->N_Q; n++)
            sbr->bs_invf_mode[1][n] = sbr->bs_invf_mode[0][n];

        sbr_envelope(ld, sbr, 0);
        sbr_noise(ld, sbr, 0);
        sbr_envelope(ld, sbr, 1);
        sbr_noise(ld, sbr, 1);

        memset(sbr->bs_add_harmonic[0], 0, 64*sizeof(uint8_t));
        memset(sbr->bs_add_harmonic[1], 0, 64*sizeof(uint8_t));

        sbr->bs_add_harmonic_flag[0] = faad_get1bit(ld
            DEBUGVAR(1,231,"sbr_channel_pair_element(): bs_add_harmonic_flag[0]"));
        if (sbr->bs_add_harmonic_flag[0])
            sinusoidal_coding(ld, sbr, 0);

        sbr->bs_add_harmonic_flag[1] = faad_get1bit(ld
            DEBUGVAR(1,232,"sbr_channel_pair_element(): bs_add_harmonic_flag[1]"));
        if (sbr->bs_add_harmonic_flag[1])
            sinusoidal_coding(ld, sbr, 1);
    } else {
        uint8_t saved_t_E[6] = {0}, saved_t_Q[3] = {0};
        uint8_t saved_L_E = sbr->L_E[0];
        uint8_t saved_L_Q = sbr->L_Q[0];
        uint8_t saved_frame_class = sbr->bs_frame_class[0];

        for (n = 0; n < saved_L_E; n++)
            saved_t_E[n] = sbr->t_E[0][n];
        for (n = 0; n < saved_L_Q; n++)
            saved_t_Q[n] = sbr->t_Q[0][n];

        if ((result = sbr_grid(ld, sbr, 0)) > 0)
            return result;
        if ((result = sbr_grid(ld, sbr, 1)) > 0)
        {
            /* restore first channel data as well */
            sbr->bs_frame_class[0] = saved_frame_class;
            sbr->L_E[0] = saved_L_E;
            sbr->L_Q[0] = saved_L_Q;
            for (n = 0; n < 6; n++)
                sbr->t_E[0][n] = saved_t_E[n];
            for (n = 0; n < 3; n++)
                sbr->t_Q[0][n] = saved_t_Q[n];

            return result;
        }
        sbr_dtdf(ld, sbr, 0);
        sbr_dtdf(ld, sbr, 1);
        invf_mode(ld, sbr, 0);
        invf_mode(ld, sbr, 1);
        sbr_envelope(ld, sbr, 0);
        sbr_envelope(ld, sbr, 1);
        sbr_noise(ld, sbr, 0);
        sbr_noise(ld, sbr, 1);

        memset(sbr->bs_add_harmonic[0], 0, 64*sizeof(uint8_t));
        memset(sbr->bs_add_harmonic[1], 0, 64*sizeof(uint8_t));

        sbr->bs_add_harmonic_flag[0] = faad_get1bit(ld
            DEBUGVAR(1,239,"sbr_channel_pair_element(): bs_add_harmonic_flag[0]"));
        if (sbr->bs_add_harmonic_flag[0])
            sinusoidal_coding(ld, sbr, 0);

        sbr->bs_add_harmonic_flag[1] = faad_get1bit(ld
            DEBUGVAR(1,240,"sbr_channel_pair_element(): bs_add_harmonic_flag[1]"));
        if (sbr->bs_add_harmonic_flag[1])
            sinusoidal_coding(ld, sbr, 1);
    }
#ifndef FIXED_POINT
    envelope_noise_dequantisation(sbr, 0);
    envelope_noise_dequantisation(sbr, 1);

    if (sbr->bs_coupling)
        unmap_envelope_noise(sbr);
#endif

    sbr->bs_extended_data = faad_get1bit(ld
        DEBUGVAR(1,233,"sbr_channel_pair_element(): bs_extended_data[0]"));
    if (sbr->bs_extended_data)
    {
        uint16_t nr_bits_left;
        uint16_t cnt = (uint16_t)faad_getbits(ld, 4
            DEBUGVAR(1,234,"sbr_channel_pair_element(): bs_extension_size"));
        if (cnt == 15)
        {
            cnt += (uint16_t)faad_getbits(ld, 8
                DEBUGVAR(1,235,"sbr_channel_pair_element(): bs_esc_count"));
        }

        nr_bits_left = 8 * cnt;
        while (nr_bits_left > 7)
        {
            uint16_t tmp_nr_bits = 0;

            sbr->bs_extension_id = (uint8_t)faad_getbits(ld, 2
                DEBUGVAR(1,236,"sbr_channel_pair_element(): bs_extension_id"));
            tmp_nr_bits += 2;
            tmp_nr_bits += sbr_extension(ld, sbr, sbr->bs_extension_id, nr_bits_left);

            /* check if the data read is bigger than the number of available bits */
            if (tmp_nr_bits > nr_bits_left)
                return 1;

            nr_bits_left -= tmp_nr_bits;
        }

        /* Corrigendum */
        if (nr_bits_left > 0)
        {
            faad_getbits(ld, nr_bits_left
                DEBUGVAR(1,280,"sbr_channel_pair_element(): nr_bits_left"));
        }
    }

    return 0;
}

/* integer log[2](x): input range [0,10) */
static int8_t sbr_log2(const int8_t val)
{
    static const int8_t log2tab[] = { 0, 0, 1, 2, 2, 3, 3, 3, 3, 4 };
    if (val < 10 && val >= 0)
        return log2tab[val];
    else
        return 0;
}


/* table 7 */
static uint8_t sbr_grid(bitfile *ld, sbr_info *sbr, uint8_t ch)
{
    uint8_t i, env, rel, result;
    uint8_t bs_abs_bord, bs_abs_bord_1;
    uint8_t bs_num_env = 0;
    uint8_t saved_L_E = sbr->L_E[ch];
    uint8_t saved_L_Q = sbr->L_Q[ch];
    uint8_t saved_frame_class = sbr->bs_frame_class[ch];

    sbr->bs_frame_class[ch] = (uint8_t)faad_getbits(ld, 2
        DEBUGVAR(1,248,"sbr_grid(): bs_frame_class"));

    switch (sbr->bs_frame_class[ch])
    {
    case FIXFIX:
        i = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,249,"sbr_grid(): bs_num_env_raw"));

        bs_num_env = min(1 << i, 5);

        i = (uint8_t)faad_get1bit(ld
            DEBUGVAR(1,250,"sbr_grid(): bs_freq_res_flag"));
        for (env = 0; env < bs_num_env; env++)
            sbr->f[ch][env] = i;

        sbr->abs_bord_lead[ch] = 0;
        sbr->abs_bord_trail[ch] = sbr->numTimeSlots;
        sbr->n_rel_lead[ch] = bs_num_env - 1;
        sbr->n_rel_trail[ch] = 0;
        break;

    case FIXVAR:
        bs_abs_bord = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,251,"sbr_grid(): bs_abs_bord")) + sbr->numTimeSlots;
        bs_num_env = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,252,"sbr_grid(): bs_num_env")) + 1;

        for (rel = 0; rel < bs_num_env-1; rel++)
        {
            sbr->bs_rel_bord[ch][rel] = 2 * (uint8_t)faad_getbits(ld, 2
                DEBUGVAR(1,253,"sbr_grid(): bs_rel_bord")) + 2;
        }
        i = sbr_log2(bs_num_env + 1);
        sbr->bs_pointer[ch] = (uint8_t)faad_getbits(ld, i
            DEBUGVAR(1,254,"sbr_grid(): bs_pointer"));

        for (env = 0; env < bs_num_env; env++)
        {
            sbr->f[ch][bs_num_env - env - 1] = (uint8_t)faad_get1bit(ld
                DEBUGVAR(1,255,"sbr_grid(): bs_freq_res"));
        }

        sbr->abs_bord_lead[ch] = 0;
        sbr->abs_bord_trail[ch] = bs_abs_bord;
        sbr->n_rel_lead[ch] = 0;
        sbr->n_rel_trail[ch] = bs_num_env - 1;
        break;

    case VARFIX:
        bs_abs_bord = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,256,"sbr_grid(): bs_abs_bord"));
        bs_num_env = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,257,"sbr_grid(): bs_num_env")) + 1;

        for (rel = 0; rel < bs_num_env-1; rel++)
        {
            sbr->bs_rel_bord[ch][rel] = 2 * (uint8_t)faad_getbits(ld, 2
                DEBUGVAR(1,258,"sbr_grid(): bs_rel_bord")) + 2;
        }
        i = sbr_log2(bs_num_env + 1);
        sbr->bs_pointer[ch] = (uint8_t)faad_getbits(ld, i
            DEBUGVAR(1,259,"sbr_grid(): bs_pointer"));

        for (env = 0; env < bs_num_env; env++)
        {
            sbr->f[ch][env] = (uint8_t)faad_get1bit(ld
                DEBUGVAR(1,260,"sbr_grid(): bs_freq_res"));
        }

        sbr->abs_bord_lead[ch] = bs_abs_bord;
        sbr->abs_bord_trail[ch] = sbr->numTimeSlots;
        sbr->n_rel_lead[ch] = bs_num_env - 1;
        sbr->n_rel_trail[ch] = 0;
        break;

    case VARVAR:
        bs_abs_bord = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,261,"sbr_grid(): bs_abs_bord_0"));
        bs_abs_bord_1 = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,262,"sbr_grid(): bs_abs_bord_1")) + sbr->numTimeSlots;
        sbr->bs_num_rel_0[ch] = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,263,"sbr_grid(): bs_num_rel_0"));
        sbr->bs_num_rel_1[ch] = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,264,"sbr_grid(): bs_num_rel_1"));

        bs_num_env = min(5, sbr->bs_num_rel_0[ch] + sbr->bs_num_rel_1[ch] + 1);

        for (rel = 0; rel < sbr->bs_num_rel_0[ch]; rel++)
        {
            sbr->bs_rel_bord_0[ch][rel] = 2 * (uint8_t)faad_getbits(ld, 2
                DEBUGVAR(1,265,"sbr_grid(): bs_rel_bord")) + 2;
        }
        for(rel = 0; rel < sbr->bs_num_rel_1[ch]; rel++)
        {
            sbr->bs_rel_bord_1[ch][rel] = 2 * (uint8_t)faad_getbits(ld, 2
                DEBUGVAR(1,266,"sbr_grid(): bs_rel_bord")) + 2;
        }
        i = sbr_log2(sbr->bs_num_rel_0[ch] + sbr->bs_num_rel_1[ch] + 2);
        sbr->bs_pointer[ch] = (uint8_t)faad_getbits(ld, i
            DEBUGVAR(1,267,"sbr_grid(): bs_pointer"));

        for (env = 0; env < bs_num_env; env++)
        {
            sbr->f[ch][env] = (uint8_t)faad_get1bit(ld
                DEBUGVAR(1,268,"sbr_grid(): bs_freq_res"));
        }

        sbr->abs_bord_lead[ch] = bs_abs_bord;
        sbr->abs_bord_trail[ch] = bs_abs_bord_1;
        sbr->n_rel_lead[ch] = sbr->bs_num_rel_0[ch];
        sbr->n_rel_trail[ch] = sbr->bs_num_rel_1[ch];
        break;
    }

    if (sbr->bs_frame_class[ch] == VARVAR)
        sbr->L_E[ch] = min(bs_num_env, 5);
    else
        sbr->L_E[ch] = min(bs_num_env, 4);

    if (sbr->L_E[ch] <= 0)
        return 1;

    if (sbr->L_E[ch] > 1)
        sbr->L_Q[ch] = 2;
    else
        sbr->L_Q[ch] = 1;

    /* TODO: this code can probably be integrated into the code above! */
    if ((result = envelope_time_border_vector(sbr, ch)) > 0)
    {
        sbr->bs_frame_class[ch] = saved_frame_class;
        sbr->L_E[ch] = saved_L_E;
        sbr->L_Q[ch] = saved_L_Q;
        return result;
    }
    noise_floor_time_border_vector(sbr, ch);

#if 0
    for (env = 0; env < bs_num_env; env++)
    {
        printf("freq_res[ch:%d][env:%d]: %d\n", ch, env, sbr->f[ch][env]);
    }
#endif

    return 0;
}

/* table 8 */
static void sbr_dtdf(bitfile *ld, sbr_info *sbr, uint8_t ch)
{
    uint8_t i;

    for (i = 0; i < sbr->L_E[ch]; i++)
    {
        sbr->bs_df_env[ch][i] = faad_get1bit(ld
            DEBUGVAR(1,269,"sbr_dtdf(): bs_df_env"));
    }

    for (i = 0; i < sbr->L_Q[ch]; i++)
    {
        sbr->bs_df_noise[ch][i] = faad_get1bit(ld
            DEBUGVAR(1,270,"sbr_dtdf(): bs_df_noise"));
    }
}

/* table 9 */
static void invf_mode(bitfile *ld, sbr_info *sbr, uint8_t ch)
{
    uint8_t n;

    for (n = 0; n < sbr->N_Q; n++)
    {
        sbr->bs_invf_mode[ch][n] = (uint8_t)faad_getbits(ld, 2
            DEBUGVAR(1,271,"invf_mode(): bs_invf_mode"));
    }
}

static uint16_t sbr_extension(bitfile *ld, sbr_info *sbr,
                              uint8_t bs_extension_id, uint16_t num_bits_left)
{
#ifdef PS_DEC
    uint8_t header;
    uint16_t ret;
#endif

    switch (bs_extension_id)
    {
#ifdef PS_DEC
    case EXTENSION_ID_PS:
        if (!sbr->ps)
        {
            sbr->ps = ps_init(get_sr_index(sbr->sample_rate));
        }
        ret = ps_data(sbr->ps, ld, &header);

        /* enable PS if and only if: a header has been decoded */
        if (sbr->ps_used == 0 && header == 1)
        {
            sbr->ps_used = 1;
        }

        return ret;
#endif
#ifdef DRM_PS
    case DRM_PARAMETRIC_STEREO:
        sbr->ps_used = 1;
        if (!sbr->drm_ps)
        {
            sbr->drm_ps = drm_ps_init();
        }
        return drm_ps_data(sbr->drm_ps, ld);
#endif
    default:
        sbr->bs_extension_data = (uint8_t)faad_getbits(ld, 6
            DEBUGVAR(1,279,"sbr_single_channel_element(): bs_extension_data"));
        return 6;
    }
}

/* table 12 */
static void sinusoidal_coding(bitfile *ld, sbr_info *sbr, uint8_t ch)
{
    uint8_t n;

    for (n = 0; n < sbr->N_high; n++)
    {
        sbr->bs_add_harmonic[ch][n] = faad_get1bit(ld
            DEBUGVAR(1,278,"sinusoidal_coding(): bs_add_harmonic"));
    }
}


#endif /* SBR_DEC */