/* * AC-3 DSP functions * Copyright (c) 2011 Justin Ruggles * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #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_uintp2((psd[bin] - m) >> 5, 6); 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_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; } } } static void apply_window_int16_c(int16_t *output, const int16_t *input, const int16_t *window, unsigned int len) { int i; int len2 = len >> 1; for (i = 0; i < len2; i++) { int16_t w = window[i]; output[i] = (MUL16(input[i], w) + (1 << 14)) >> 15; output[len-i-1] = (MUL16(input[len-i-1], w) + (1 << 14)) >> 15; } } 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->downmix = ac3_downmix_c; c->apply_window_int16 = apply_window_int16_c; if (ARCH_ARM) ff_ac3dsp_init_arm(c, bit_exact); if (ARCH_X86) ff_ac3dsp_init_x86(c, bit_exact); }