317 lines
11 KiB
C
317 lines
11 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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#define ALT_BITSTREAM_READER_LE
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#include "avcodec.h"
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#include "get_bits.h"
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// input and output sizes in byte
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#define GSM_BLOCK_SIZE 33
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#define GSM_MS_BLOCK_SIZE 65
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#define GSM_FRAME_SIZE 160
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typedef struct {
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int16_t ref_buf[280];
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int v[9];
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int lar[2][8];
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int lar_idx;
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int msr;
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} GSMContext;
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static av_cold int gsm_init(AVCodecContext *avctx)
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{
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avctx->channels = 1;
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if (!avctx->sample_rate)
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avctx->sample_rate = 8000;
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avctx->sample_fmt = SAMPLE_FMT_S16;
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switch (avctx->codec_id) {
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case CODEC_ID_GSM:
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avctx->frame_size = GSM_FRAME_SIZE;
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avctx->block_align = GSM_BLOCK_SIZE;
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break;
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case CODEC_ID_GSM_MS:
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avctx->frame_size = 2 * GSM_FRAME_SIZE;
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avctx->block_align = GSM_MS_BLOCK_SIZE;
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}
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return 0;
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}
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static const int16_t dequant_tab[64][8] = {
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{ -28, -20, -12, -4, 4, 12, 20, 28},
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{ -56, -40, -24, -8, 8, 24, 40, 56},
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{ -84, -60, -36, -12, 12, 36, 60, 84},
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{ -112, -80, -48, -16, 16, 48, 80, 112},
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{ -140, -100, -60, -20, 20, 60, 100, 140},
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{ -168, -120, -72, -24, 24, 72, 120, 168},
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{ -196, -140, -84, -28, 28, 84, 140, 196},
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{ -224, -160, -96, -32, 32, 96, 160, 224},
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{ -252, -180, -108, -36, 36, 108, 180, 252},
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{ -280, -200, -120, -40, 40, 120, 200, 280},
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{ -308, -220, -132, -44, 44, 132, 220, 308},
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{ -336, -240, -144, -48, 48, 144, 240, 336},
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{ -364, -260, -156, -52, 52, 156, 260, 364},
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{ -392, -280, -168, -56, 56, 168, 280, 392},
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{ -420, -300, -180, -60, 60, 180, 300, 420},
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{ -448, -320, -192, -64, 64, 192, 320, 448},
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{ -504, -360, -216, -72, 72, 216, 360, 504},
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{ -560, -400, -240, -80, 80, 240, 400, 560},
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{ -616, -440, -264, -88, 88, 264, 440, 616},
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{ -672, -480, -288, -96, 96, 288, 480, 672},
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{ -728, -520, -312, -104, 104, 312, 520, 728},
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{ -784, -560, -336, -112, 112, 336, 560, 784},
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{ -840, -600, -360, -120, 120, 360, 600, 840},
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{ -896, -640, -384, -128, 128, 384, 640, 896},
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{ -1008, -720, -432, -144, 144, 432, 720, 1008},
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{ -1120, -800, -480, -160, 160, 480, 800, 1120},
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{ -1232, -880, -528, -176, 176, 528, 880, 1232},
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{ -1344, -960, -576, -192, 192, 576, 960, 1344},
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{ -1456, -1040, -624, -208, 208, 624, 1040, 1456},
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{ -1568, -1120, -672, -224, 224, 672, 1120, 1568},
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{ -1680, -1200, -720, -240, 240, 720, 1200, 1680},
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{ -1792, -1280, -768, -256, 256, 768, 1280, 1792},
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{ -2016, -1440, -864, -288, 288, 864, 1440, 2016},
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{ -2240, -1600, -960, -320, 320, 960, 1600, 2240},
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{ -2464, -1760, -1056, -352, 352, 1056, 1760, 2464},
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{ -2688, -1920, -1152, -384, 384, 1152, 1920, 2688},
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{ -2912, -2080, -1248, -416, 416, 1248, 2080, 2912},
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{ -3136, -2240, -1344, -448, 448, 1344, 2240, 3136},
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{ -3360, -2400, -1440, -480, 480, 1440, 2400, 3360},
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{ -3584, -2560, -1536, -512, 512, 1536, 2560, 3584},
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{ -4032, -2880, -1728, -576, 576, 1728, 2880, 4032},
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{ -4480, -3200, -1920, -640, 640, 1920, 3200, 4480},
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{ -4928, -3520, -2112, -704, 704, 2112, 3520, 4928},
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{ -5376, -3840, -2304, -768, 768, 2304, 3840, 5376},
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{ -5824, -4160, -2496, -832, 832, 2496, 4160, 5824},
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{ -6272, -4480, -2688, -896, 896, 2688, 4480, 6272},
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{ -6720, -4800, -2880, -960, 960, 2880, 4800, 6720},
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{ -7168, -5120, -3072, -1024, 1024, 3072, 5120, 7168},
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{ -8063, -5759, -3456, -1152, 1152, 3456, 5760, 8064},
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{ -8959, -6399, -3840, -1280, 1280, 3840, 6400, 8960},
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{ -9855, -7039, -4224, -1408, 1408, 4224, 7040, 9856},
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{-10751, -7679, -4608, -1536, 1536, 4608, 7680, 10752},
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{-11647, -8319, -4992, -1664, 1664, 4992, 8320, 11648},
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{-12543, -8959, -5376, -1792, 1792, 5376, 8960, 12544},
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{-13439, -9599, -5760, -1920, 1920, 5760, 9600, 13440},
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{-14335, -10239, -6144, -2048, 2048, 6144, 10240, 14336},
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{-16127, -11519, -6912, -2304, 2304, 6912, 11519, 16127},
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{-17919, -12799, -7680, -2560, 2560, 7680, 12799, 17919},
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{-19711, -14079, -8448, -2816, 2816, 8448, 14079, 19711},
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{-21503, -15359, -9216, -3072, 3072, 9216, 15359, 21503},
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{-23295, -16639, -9984, -3328, 3328, 9984, 16639, 23295},
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{-25087, -17919, -10752, -3584, 3584, 10752, 17919, 25087},
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{-26879, -19199, -11520, -3840, 3840, 11520, 19199, 26879},
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{-28671, -20479, -12288, -4096, 4096, 12288, 20479, 28671}
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};
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static void apcm_dequant_add(GetBitContext *gb, int16_t *dst)
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{
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int i;
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int maxidx = get_bits(gb, 6);
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const int16_t *tab = dequant_tab[maxidx];
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for (i = 0; i < 13; i++)
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dst[3*i] += tab[get_bits(gb, 3)];
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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 const uint16_t long_term_gain_tab[4] = {
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3277, 11469, 21299, 32767
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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 = 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) << 1;
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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 << 1) & ~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)
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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);
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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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static int gsm_decode_frame(AVCodecContext *avctx, void *data,
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int *data_size, AVPacket *avpkt)
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{
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int res;
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GetBitContext gb;
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const uint8_t *buf = avpkt->data;
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int buf_size = avpkt->size;
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int16_t *samples = data;
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int frame_bytes = 2 * avctx->frame_size;
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if (*data_size < frame_bytes)
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return -1;
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*data_size = 0;
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if(buf_size < avctx->block_align)
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return AVERROR_INVALIDDATA;
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init_get_bits(&gb, buf, buf_size * 8);
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switch (avctx->codec_id) {
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case CODEC_ID_GSM:
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if (get_bits(&gb, 4) != 0xd)
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av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
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res = gsm_decode_block(avctx, samples, &gb);
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if (res < 0)
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return res;
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break;
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case CODEC_ID_GSM_MS:
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res = gsm_decode_block(avctx, samples, &gb);
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if (res < 0)
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return res;
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res = gsm_decode_block(avctx, samples + GSM_FRAME_SIZE, &gb);
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if (res < 0)
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return res;
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}
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*data_size = frame_bytes;
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return avctx->block_align;
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}
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AVCodec gsm_decoder = {
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"gsm",
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AVMEDIA_TYPE_AUDIO,
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CODEC_ID_GSM,
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sizeof(GSMContext),
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gsm_init,
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NULL,
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NULL,
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gsm_decode_frame,
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.long_name = NULL_IF_CONFIG_SMALL("GSM"),
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};
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AVCodec gsm_ms_decoder = {
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"gsm_ms",
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AVMEDIA_TYPE_AUDIO,
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CODEC_ID_GSM_MS,
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sizeof(GSMContext),
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gsm_init,
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NULL,
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NULL,
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gsm_decode_frame,
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.long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
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};
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