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5ba2a2c841
the fixed decoder discarded fractional coefficient data before the imdct, causing low-level coefficients to be truncated at large exponents. dithered bap 0 coefficients at exponent 24 were consequently quantized with a negative bias. keep ac-3 coefficients in q2, compensate during windowing, and round the affected dither symmetrically. keep the forced e-ac-3 path in q0. add a synthetic fate test covering the corrected output.
246 lines
8.4 KiB
C
246 lines
8.4 KiB
C
/*
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* Copyright (c) 2012
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* MIPS Technologies, Inc., California.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE MIPS TECHNOLOGIES, INC. ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE MIPS TECHNOLOGIES, INC. BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* Author: Stanislav Ocovaj (socovaj@mips.com)
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*
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* AC3 fixed-point decoder for MIPS platforms
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "config_components.h"
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#define USE_FIXED 1
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#include "ac3dec.h"
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#include "codec_internal.h"
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#define IMDCT_TYPE AV_TX_INT32_MDCT
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#include "ac3dec.h"
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/* Keep two fractional bits in fixed-point transform coefficients. */
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#define AC3_FIXED_COEFF_BITS 2
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#define AC3_FIXED_EXPONENT_MAX 24
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static av_always_inline int fixed_coeff_bits(const AC3DecodeContext *s)
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{
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/* ac3_fixed normally decodes AC-3. Keep Q0 when it is explicitly forced
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* to decode E-AC-3, whose AHT coefficient bounds are different. */
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return s->eac3 ? 0 : AC3_FIXED_COEFF_BITS;
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}
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static const int end_freq_inv_tab[8] =
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{
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50529027, 44278013, 39403370, 32292987, 27356480, 23729101, 20951060, 18755316
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};
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static void scale_coefs (
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int32_t *dst,
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const int32_t *src,
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int dynrng,
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int len)
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{
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int i, shift;
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unsigned mul, round;
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int temp, temp1, temp2, temp3, temp4, temp5, temp6, temp7;
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mul = (dynrng & 0x1f) + 0x20;
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shift = 4 - (sign_extend(dynrng, 9) >> 5);
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if (shift > 0 ) {
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round = 1 << (shift-1);
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for (i=0; i<len; i+=8) {
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temp = src[i] * mul;
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temp1 = src[i+1] * mul;
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temp = temp + round;
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temp2 = src[i+2] * mul;
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temp1 = temp1 + round;
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dst[i] = temp >> shift;
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temp3 = src[i+3] * mul;
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temp2 = temp2 + round;
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dst[i+1] = temp1 >> shift;
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temp4 = src[i + 4] * mul;
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temp3 = temp3 + round;
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dst[i+2] = temp2 >> shift;
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temp5 = src[i+5] * mul;
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temp4 = temp4 + round;
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dst[i+3] = temp3 >> shift;
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temp6 = src[i+6] * mul;
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dst[i+4] = temp4 >> shift;
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temp5 = temp5 + round;
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temp7 = src[i+7] * mul;
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temp6 = temp6 + round;
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dst[i+5] = temp5 >> shift;
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temp7 = temp7 + round;
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dst[i+6] = temp6 >> shift;
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dst[i+7] = temp7 >> shift;
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}
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} else {
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shift = -shift;
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mul <<= shift;
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for (i=0; i<len; i+=8) {
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dst[i] = src[i ] * mul;
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dst[i+1] = src[i+1] * mul;
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dst[i+2] = src[i+2] * mul;
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dst[i+3] = src[i+3] * mul;
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dst[i+4] = src[i+4] * mul;
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dst[i+5] = src[i+5] * mul;
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dst[i+6] = src[i+6] * mul;
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dst[i+7] = src[i+7] * mul;
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}
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}
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}
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static void scale_coefs_q2(int32_t *dst, const int32_t *src, int dynrng,
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int len)
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{
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int i, shift;
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int mul;
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mul = (dynrng & 0x1f) + 0x20;
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shift = 4 - (sign_extend(dynrng, 9) >> 5);
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/* AC-3 mantissas have magnitude at most 2^23, hence Q2 coefficients
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* have magnitude at most 2^25. Coupling uses MULH(coeff * 2^4, coord)
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* with coord < 2^31, so coupled coefficients are below 2^28.
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* Rematrixing can at most double them, keeping src below 2^29. */
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if (dynrng == 32) {
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for (i = 0; i < len; i++)
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dst[i] = src[i] * 4;
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return;
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}
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if (shift >= 4) {
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const int round = 1 << (shift - 1);
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const int unit = 1 << shift;
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/* With shift >= 4, quotient * mul is below 2^25 * 63. Splitting
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* quotient and remainder therefore keeps both products in int32_t. */
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for (i = 0; i < len; i++) {
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int quotient = src[i] >> shift;
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int remainder = src[i] - quotient * unit;
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dst[i] = quotient * mul + ((remainder * mul + round) >> shift);
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}
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} else if (shift > 0) {
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const int round = 1 << (shift - 1);
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for (i = 0; i < len; i++)
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dst[i] = av_clipl_int32(((int64_t)src[i] * mul + round) >> shift);
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} else {
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mul <<= -shift;
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for (i = 0; i < len; i++)
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dst[i] = av_clipl_int32((int64_t)src[i] * mul);
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}
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}
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/**
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* Downmix samples from original signal to stereo or mono (this is for 16-bit samples
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* and fixed point decoder - original (for 32-bit samples) is in ac3dsp.c).
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*/
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static void ac3_downmix_c_fixed16(int16_t **samples, int16_t **matrix,
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int out_ch, int in_ch, int len)
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{
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int i, j;
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int v0, v1;
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if (out_ch == 2) {
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for (i = 0; i < len; i++) {
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v0 = v1 = 0;
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for (j = 0; j < in_ch; j++) {
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v0 += samples[j][i] * matrix[0][j];
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v1 += samples[j][i] * matrix[1][j];
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}
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samples[0][i] = (v0+2048)>>12;
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samples[1][i] = (v1+2048)>>12;
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}
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} else if (out_ch == 1) {
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for (i = 0; i < len; i++) {
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v0 = 0;
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for (j = 0; j < in_ch; j++)
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v0 += samples[j][i] * matrix[0][j];
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samples[0][i] = (v0+2048)>>12;
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}
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}
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}
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#if CONFIG_EAC3_DECODER
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#include "eac3dec.c"
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#endif
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#include "ac3dec.c"
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static const AVOption options[] = {
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{ "cons_noisegen", "enable consistent noise generation", OFFSET(consistent_noise_generation), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, PAR },
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{ "drc_scale", "percentage of dynamic range compression to apply", OFFSET(drc_scale), AV_OPT_TYPE_FLOAT, {.dbl = 1.0}, 0.0, 6.0, PAR },
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{ "heavy_compr", "enable heavy dynamic range compression", OFFSET(heavy_compression), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, PAR },
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{ "downmix", "Request a specific channel layout from the decoder", OFFSET(downmix_layout), AV_OPT_TYPE_CHLAYOUT, {.str = NULL}, .flags = PAR },
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{ NULL},
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};
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static const AVClass ac3_decoder_class = {
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.class_name = "Fixed-Point AC-3 Decoder",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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const FFCodec ff_ac3_fixed_decoder = {
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.p.name = "ac3_fixed",
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CODEC_LONG_NAME("ATSC A/52A (AC-3)"),
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.p.type = AVMEDIA_TYPE_AUDIO,
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.p.id = AV_CODEC_ID_AC3,
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.p.priv_class = &ac3_decoder_class,
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.priv_data_size = sizeof (AC3DecodeContext),
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.init = ac3_decode_init,
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.flush = ac3_decode_flush,
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.close = ac3_decode_end,
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FF_CODEC_DECODE_CB(ac3_decode_frame),
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.p.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
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AV_CODEC_CAP_DR1,
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CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S16P),
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.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
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};
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