forked from KolibriOS/kolibrios
161 lines
4.9 KiB
C
161 lines
4.9 KiB
C
/*
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* gsm 06.10 decoder
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* Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
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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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/**
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* @file
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* GSM decoder
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*/
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#include "get_bits.h"
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#include "gsm.h"
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#include "gsmdec_data.h"
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static const int requant_tab[4][8] = {
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{ 0 },
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{ 0, 7 },
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{ 0, 2, 5, 7 },
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{ 0, 1, 2, 3, 4, 5, 6, 7 }
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};
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static void apcm_dequant_add(GetBitContext *gb, int16_t *dst, const int *frame_bits)
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{
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int i, val;
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int maxidx = get_bits(gb, 6);
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const int16_t *tab = ff_gsm_dequant_tab[maxidx];
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for (i = 0; i < 13; i++) {
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val = get_bits(gb, frame_bits[i]);
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dst[3*i] += tab[requant_tab[frame_bits[i]][val]];
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}
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}
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static inline int gsm_mult(int a, int b)
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{
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return (a * b + (1 << 14)) >> 15;
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}
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static void long_term_synth(int16_t *dst, int lag, int gain_idx)
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{
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int i;
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const int16_t *src = dst - lag;
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uint16_t gain = ff_gsm_long_term_gain_tab[gain_idx];
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for (i = 0; i < 40; i++)
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dst[i] = gsm_mult(gain, src[i]);
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}
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static inline int decode_log_area(int coded, int factor, int offset)
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{
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coded <<= 10;
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coded -= offset;
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return gsm_mult(coded, factor) * 2;
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}
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static av_noinline int get_rrp(int filtered)
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{
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int abs = FFABS(filtered);
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if (abs < 11059) abs <<= 1;
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else if (abs < 20070) abs += 11059;
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else abs = (abs >> 2) + 26112;
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return filtered < 0 ? -abs : abs;
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}
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static int filter_value(int in, int rrp[8], int v[9])
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{
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int i;
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for (i = 7; i >= 0; i--) {
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in -= gsm_mult(rrp[i], v[i]);
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v[i + 1] = v[i] + gsm_mult(rrp[i], in);
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}
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v[0] = in;
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return in;
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}
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static void short_term_synth(GSMContext *ctx, int16_t *dst, const int16_t *src)
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{
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int i;
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int rrp[8];
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int *lar = ctx->lar[ctx->lar_idx];
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int *lar_prev = ctx->lar[ctx->lar_idx ^ 1];
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for (i = 0; i < 8; i++)
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rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar_prev[i] >> 1) + (lar[i] >> 2));
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for (i = 0; i < 13; i++)
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dst[i] = filter_value(src[i], rrp, ctx->v);
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for (i = 0; i < 8; i++)
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rrp[i] = get_rrp((lar_prev[i] >> 1) + (lar [i] >> 1));
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for (i = 13; i < 27; i++)
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dst[i] = filter_value(src[i], rrp, ctx->v);
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for (i = 0; i < 8; i++)
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rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar [i] >> 1) + (lar[i] >> 2));
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for (i = 27; i < 40; i++)
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dst[i] = filter_value(src[i], rrp, ctx->v);
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for (i = 0; i < 8; i++)
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rrp[i] = get_rrp(lar[i]);
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for (i = 40; i < 160; i++)
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dst[i] = filter_value(src[i], rrp, ctx->v);
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ctx->lar_idx ^= 1;
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}
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static int postprocess(int16_t *data, int msr)
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{
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int i;
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for (i = 0; i < 160; i++) {
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msr = av_clip_int16(data[i] + gsm_mult(msr, 28180));
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data[i] = av_clip_int16(msr * 2) & ~7;
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}
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return msr;
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}
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static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples,
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GetBitContext *gb, int mode)
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{
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GSMContext *ctx = avctx->priv_data;
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int i;
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int16_t *ref_dst = ctx->ref_buf + 120;
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int *lar = ctx->lar[ctx->lar_idx];
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lar[0] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
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lar[1] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
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lar[2] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) + 2048*2);
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lar[3] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) - 2560*2);
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lar[4] = decode_log_area(get_bits(gb, 4), 19223, (1 << 13) + 94*2);
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lar[5] = decode_log_area(get_bits(gb, 4), 17476, (1 << 13) - 1792*2);
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lar[6] = decode_log_area(get_bits(gb, 3), 31454, (1 << 12) - 341*2);
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lar[7] = decode_log_area(get_bits(gb, 3), 29708, (1 << 12) - 1144*2);
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for (i = 0; i < 4; i++) {
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int lag = get_bits(gb, 7);
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int gain_idx = get_bits(gb, 2);
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int offset = get_bits(gb, 2);
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lag = av_clip(lag, 40, 120);
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long_term_synth(ref_dst, lag, gain_idx);
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apcm_dequant_add(gb, ref_dst + offset, ff_gsm_apcm_bits[mode][i]);
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ref_dst += 40;
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}
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memcpy(ctx->ref_buf, ctx->ref_buf + 160, 120 * sizeof(*ctx->ref_buf));
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short_term_synth(ctx, samples, ctx->ref_buf + 120);
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// for optimal speed this could be merged with short_term_synth,
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// not done yet because it is a bit ugly
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ctx->msr = postprocess(samples, ctx->msr);
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return 0;
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}
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