| /* |
| * 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" |
| |
| 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; |
| |
| /* 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; |
| int band_end = FFMIN(ff_ac3_band_start_tab[band+1], end); |
| for (; bin < band_end; bin++) { |
| int address = av_clip((psd[bin] - m) >> 5, 0, 63); |
| bap[bin] = bap_tab[address]; |
| } |
| } while (end > ff_ac3_band_start_tab[band++]); |
| } |
| |
| 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 e; |
| int v = abs(coef[i]); |
| if (v == 0) |
| e = 24; |
| else { |
| e = 23 - av_log2(v); |
| if (e >= 24) { |
| e = 24; |
| coef[i] = 0; |
| } else if (e < 0) { |
| e = 0; |
| coef[i] = av_clip(coef[i], -16777215, 16777215); |
| } |
| } |
| exp[i] = e; |
| } |
| } |
| |
| 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; |
| |
| if (ARCH_ARM) |
| ff_ac3dsp_init_arm(c, bit_exact); |
| if (HAVE_MMX) |
| ff_ac3dsp_init_x86(c, bit_exact); |
| } |