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316 lines
11 KiB
316 lines
11 KiB
/* |
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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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