mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
166 lines
5.0 KiB
166 lines
5.0 KiB
/* |
|
* AC-3 DSP utils |
|
* 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" |
|
|
|
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 int ac3_compute_mantissa_size_c(int mant_cnt[5], uint8_t *bap, |
|
int nb_coefs) |
|
{ |
|
int bits, b, i; |
|
|
|
bits = 0; |
|
for (i = 0; i < nb_coefs; i++) { |
|
b = bap[i]; |
|
if (b <= 4) { |
|
// bap=1 to bap=4 will be counted in compute_mantissa_size_final |
|
mant_cnt[b]++; |
|
} else if (b <= 13) { |
|
// bap=5 to bap=13 use (bap-1) bits |
|
bits += b - 1; |
|
} else { |
|
// bap=14 uses 14 bits and bap=15 uses 16 bits |
|
bits += (b == 14) ? 14 : 16; |
|
} |
|
} |
|
return bits; |
|
} |
|
|
|
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->compute_mantissa_size = ac3_compute_mantissa_size_c; |
|
|
|
if (ARCH_ARM) |
|
ff_ac3dsp_init_arm(c, bit_exact); |
|
if (HAVE_MMX) |
|
ff_ac3dsp_init_x86(c, bit_exact); |
|
}
|
|
|