Subversion Repositories Kolibri OS

/*

 * AC-3 DSP utils

 * Copyright (c) 2011 Justin Ruggles

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

#include "libavutil/avassert.h"

#include "avcodec.h"

#include "ac3.h"

#include "ac3dsp.h"

#include "mathops.h"

static void ac3_exponent_min_c(uint8_t *exp, int num_reuse_blocks, int nb_coefs)

{

    int blk, i;

    if (!num_reuse_blocks)

        return;

    for (i = 0; i < nb_coefs; i++) {

        uint8_t min_exp = *exp;

        uint8_t *exp1 = exp + 256;

        for (blk = 0; blk < num_reuse_blocks; blk++) {

            uint8_t next_exp = *exp1;

            if (next_exp < min_exp)

                min_exp = next_exp;

            exp1 += 256;

        }

        *exp++ = min_exp;

    }

}

static int ac3_max_msb_abs_int16_c(const int16_t *src, int len)

{

    int i, v = 0;

    for (i = 0; i < len; i++)

        v |= abs(src[i]);

    return v;

}

static void ac3_lshift_int16_c(int16_t *src, unsigned int len,

                               unsigned int shift)

{

    uint32_t *src32 = (uint32_t *)src;

    const uint32_t mask = ~(((1 << shift) - 1) << 16);

    int i;

    len >>= 1;

    for (i = 0; i < len; i += 8) {

        src32[i  ] = (src32[i  ] << shift) & mask;

        src32[i+1] = (src32[i+1] << shift) & mask;

        src32[i+2] = (src32[i+2] << shift) & mask;

        src32[i+3] = (src32[i+3] << shift) & mask;

        src32[i+4] = (src32[i+4] << shift) & mask;

        src32[i+5] = (src32[i+5] << shift) & mask;

        src32[i+6] = (src32[i+6] << shift) & mask;

        src32[i+7] = (src32[i+7] << shift) & mask;

    }

}

static void ac3_rshift_int32_c(int32_t *src, unsigned int len,

                               unsigned int shift)

{

    do {

        *src++ >>= shift;

        *src++ >>= shift;

        *src++ >>= shift;

        *src++ >>= shift;

        *src++ >>= shift;

        *src++ >>= shift;

        *src++ >>= shift;

        *src++ >>= shift;

        len -= 8;

    } while (len > 0);

}

static void float_to_fixed24_c(int32_t *dst, const float *src, unsigned int len)

{

    const float scale = 1 << 24;

    do {

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        *dst++ = lrintf(*src++ * scale);

        len -= 8;

    } while (len > 0);

}

static void ac3_bit_alloc_calc_bap_c(int16_t *mask, int16_t *psd,

                                     int start, int end,

                                     int snr_offset, int floor,

                                     const uint8_t *bap_tab, uint8_t *bap)

{

    int bin, band, band_end;

    /* special case, if snr offset is -960, set all bap's to zero */

    if (snr_offset == -960) {

        memset(bap, 0, AC3_MAX_COEFS);

        return;

    }

    bin  = start;

    band = ff_ac3_bin_to_band_tab[start];

    do {

        int m = (FFMAX(mask[band] - snr_offset - floor, 0) & 0x1FE0) + floor;

        band_end = ff_ac3_band_start_tab[++band];

        band_end = FFMIN(band_end, end);

        for (; bin < band_end; bin++) {

            int address = av_clip((psd[bin] - m) >> 5, 0, 63);

            bap[bin] = bap_tab[address];

        }

    } while (end > band_end);

}

static void ac3_update_bap_counts_c(uint16_t mant_cnt[16], uint8_t *bap,

                                    int len)

{

    while (len-- > 0)

        mant_cnt[bap[len]]++;

}

DECLARE_ALIGNED(16, const uint16_t, ff_ac3_bap_bits)[16] = {

    0,  0,  0,  3,  0,  4,  5,  6,  7,  8,  9, 10, 11, 12, 14, 16

};

static int ac3_compute_mantissa_size_c(uint16_t mant_cnt[6][16])

{

    int blk, bap;

    int bits = 0;

    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {

        // bap=1 : 3 mantissas in 5 bits

        bits += (mant_cnt[blk][1] / 3) * 5;

        // bap=2 : 3 mantissas in 7 bits

        // bap=4 : 2 mantissas in 7 bits

        bits += ((mant_cnt[blk][2] / 3) + (mant_cnt[blk][4] >> 1)) * 7;

        // bap=3 : 1 mantissa in 3 bits

        bits += mant_cnt[blk][3] * 3;

        // bap=5 to 15 : get bits per mantissa from table

        for (bap = 5; bap < 16; bap++)

            bits += mant_cnt[blk][bap] * ff_ac3_bap_bits[bap];

    }

    return bits;

}

static void ac3_extract_exponents_c(uint8_t *exp, int32_t *coef, int nb_coefs)

{

    int i;

    for (i = 0; i < nb_coefs; i++) {

        int v = abs(coef[i]);

        exp[i] = v ? 23 - av_log2(v) : 24;

    }

}

static void ac3_sum_square_butterfly_int32_c(int64_t sum[4],

                                             const int32_t *coef0,

                                             const int32_t *coef1,

                                             int len)

{

    int i;

    sum[0] = sum[1] = sum[2] = sum[3] = 0;

    for (i = 0; i < len; i++) {

        int lt = coef0[i];

        int rt = coef1[i];

        int md = lt + rt;

        int sd = lt - rt;

        MAC64(sum[0], lt, lt);

        MAC64(sum[1], rt, rt);

        MAC64(sum[2], md, md);

        MAC64(sum[3], sd, sd);

    }

}

static void ac3_sum_square_butterfly_float_c(float sum[4],

                                             const float *coef0,

                                             const float *coef1,

                                             int len)

{

    int i;

    sum[0] = sum[1] = sum[2] = sum[3] = 0;

    for (i = 0; i < len; i++) {

        float lt = coef0[i];

        float rt = coef1[i];

        float md = lt + rt;

        float sd = lt - rt;

        sum[0] += lt * lt;

        sum[1] += rt * rt;

        sum[2] += md * md;

        sum[3] += sd * sd;

    }

}

static void ac3_downmix_c(float **samples, float (*matrix)[2],

                          int out_ch, int in_ch, int len)

{

    int i, j;

    float v0, v1;

    if (out_ch == 2) {

        for (i = 0; i < len; i++) {

            v0 = v1 = 0.0f;

            for (j = 0; j < in_ch; j++) {

                v0 += samples[j][i] * matrix[j][0];

                v1 += samples[j][i] * matrix[j][1];

            }

            samples[0][i] = v0;

            samples[1][i] = v1;

        }

    } else if (out_ch == 1) {

        for (i = 0; i < len; i++) {

            v0 = 0.0f;

            for (j = 0; j < in_ch; j++)

                v0 += samples[j][i] * matrix[j][0];

            samples[0][i] = v0;

        }

    }

}

av_cold void ff_ac3dsp_init(AC3DSPContext *c, int bit_exact)

{

    c->ac3_exponent_min = ac3_exponent_min_c;

    c->ac3_max_msb_abs_int16 = ac3_max_msb_abs_int16_c;

    c->ac3_lshift_int16 = ac3_lshift_int16_c;

    c->ac3_rshift_int32 = ac3_rshift_int32_c;

    c->float_to_fixed24 = float_to_fixed24_c;

    c->bit_alloc_calc_bap = ac3_bit_alloc_calc_bap_c;

    c->update_bap_counts = ac3_update_bap_counts_c;

    c->compute_mantissa_size = ac3_compute_mantissa_size_c;

    c->extract_exponents = ac3_extract_exponents_c;

    c->sum_square_butterfly_int32 = ac3_sum_square_butterfly_int32_c;

    c->sum_square_butterfly_float = ac3_sum_square_butterfly_float_c;

    c->downmix = ac3_downmix_c;

    if (ARCH_ARM)

        ff_ac3dsp_init_arm(c, bit_exact);

    if (ARCH_X86)

        ff_ac3dsp_init_x86(c, bit_exact);

    if (ARCH_MIPS)

        ff_ac3dsp_init_mips(c, bit_exact);

}