Add native GSM 06.10 audio decoder.
[libav.git] / libavcodec / gsmdec.c
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b576934d
RD
1/*
2 * gsm 06.10 decoder
3 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * GSM decoder
25 */
26
27#define ALT_BITSTREAM_READER_LE
28#include "avcodec.h"
29#include "get_bits.h"
30
31// input and output sizes in byte
32#define GSM_BLOCK_SIZE 33
33#define GSM_MS_BLOCK_SIZE 65
34#define GSM_FRAME_SIZE 160
35
36typedef struct {
37 int16_t ref_buf[280];
38 int v[9];
39 int lar[2][8];
40 int lar_idx;
41 int msr;
42} GSMContext;
43
44static av_cold int gsm_init(AVCodecContext *avctx)
45{
46 avctx->channels = 1;
47 if (!avctx->sample_rate)
48 avctx->sample_rate = 8000;
49 avctx->sample_fmt = SAMPLE_FMT_S16;
50
51 switch (avctx->codec_id) {
52 case CODEC_ID_GSM:
53 avctx->frame_size = GSM_FRAME_SIZE;
54 avctx->block_align = GSM_BLOCK_SIZE;
55 break;
56 case CODEC_ID_GSM_MS:
57 avctx->frame_size = 2 * GSM_FRAME_SIZE;
58 avctx->block_align = GSM_MS_BLOCK_SIZE;
59 }
60
61 return 0;
62}
63
64static const int16_t dequant_tab[64][8] = {
65 { -28, -20, -12, -4, 4, 12, 20, 28},
66 { -56, -40, -24, -8, 8, 24, 40, 56},
67 { -84, -60, -36, -12, 12, 36, 60, 84},
68 { -112, -80, -48, -16, 16, 48, 80, 112},
69 { -140, -100, -60, -20, 20, 60, 100, 140},
70 { -168, -120, -72, -24, 24, 72, 120, 168},
71 { -196, -140, -84, -28, 28, 84, 140, 196},
72 { -224, -160, -96, -32, 32, 96, 160, 224},
73 { -252, -180, -108, -36, 36, 108, 180, 252},
74 { -280, -200, -120, -40, 40, 120, 200, 280},
75 { -308, -220, -132, -44, 44, 132, 220, 308},
76 { -336, -240, -144, -48, 48, 144, 240, 336},
77 { -364, -260, -156, -52, 52, 156, 260, 364},
78 { -392, -280, -168, -56, 56, 168, 280, 392},
79 { -420, -300, -180, -60, 60, 180, 300, 420},
80 { -448, -320, -192, -64, 64, 192, 320, 448},
81 { -504, -360, -216, -72, 72, 216, 360, 504},
82 { -560, -400, -240, -80, 80, 240, 400, 560},
83 { -616, -440, -264, -88, 88, 264, 440, 616},
84 { -672, -480, -288, -96, 96, 288, 480, 672},
85 { -728, -520, -312, -104, 104, 312, 520, 728},
86 { -784, -560, -336, -112, 112, 336, 560, 784},
87 { -840, -600, -360, -120, 120, 360, 600, 840},
88 { -896, -640, -384, -128, 128, 384, 640, 896},
89 { -1008, -720, -432, -144, 144, 432, 720, 1008},
90 { -1120, -800, -480, -160, 160, 480, 800, 1120},
91 { -1232, -880, -528, -176, 176, 528, 880, 1232},
92 { -1344, -960, -576, -192, 192, 576, 960, 1344},
93 { -1456, -1040, -624, -208, 208, 624, 1040, 1456},
94 { -1568, -1120, -672, -224, 224, 672, 1120, 1568},
95 { -1680, -1200, -720, -240, 240, 720, 1200, 1680},
96 { -1792, -1280, -768, -256, 256, 768, 1280, 1792},
97 { -2016, -1440, -864, -288, 288, 864, 1440, 2016},
98 { -2240, -1600, -960, -320, 320, 960, 1600, 2240},
99 { -2464, -1760, -1056, -352, 352, 1056, 1760, 2464},
100 { -2688, -1920, -1152, -384, 384, 1152, 1920, 2688},
101 { -2912, -2080, -1248, -416, 416, 1248, 2080, 2912},
102 { -3136, -2240, -1344, -448, 448, 1344, 2240, 3136},
103 { -3360, -2400, -1440, -480, 480, 1440, 2400, 3360},
104 { -3584, -2560, -1536, -512, 512, 1536, 2560, 3584},
105 { -4032, -2880, -1728, -576, 576, 1728, 2880, 4032},
106 { -4480, -3200, -1920, -640, 640, 1920, 3200, 4480},
107 { -4928, -3520, -2112, -704, 704, 2112, 3520, 4928},
108 { -5376, -3840, -2304, -768, 768, 2304, 3840, 5376},
109 { -5824, -4160, -2496, -832, 832, 2496, 4160, 5824},
110 { -6272, -4480, -2688, -896, 896, 2688, 4480, 6272},
111 { -6720, -4800, -2880, -960, 960, 2880, 4800, 6720},
112 { -7168, -5120, -3072, -1024, 1024, 3072, 5120, 7168},
113 { -8063, -5759, -3456, -1152, 1152, 3456, 5760, 8064},
114 { -8959, -6399, -3840, -1280, 1280, 3840, 6400, 8960},
115 { -9855, -7039, -4224, -1408, 1408, 4224, 7040, 9856},
116 {-10751, -7679, -4608, -1536, 1536, 4608, 7680, 10752},
117 {-11647, -8319, -4992, -1664, 1664, 4992, 8320, 11648},
118 {-12543, -8959, -5376, -1792, 1792, 5376, 8960, 12544},
119 {-13439, -9599, -5760, -1920, 1920, 5760, 9600, 13440},
120 {-14335, -10239, -6144, -2048, 2048, 6144, 10240, 14336},
121 {-16127, -11519, -6912, -2304, 2304, 6912, 11519, 16127},
122 {-17919, -12799, -7680, -2560, 2560, 7680, 12799, 17919},
123 {-19711, -14079, -8448, -2816, 2816, 8448, 14079, 19711},
124 {-21503, -15359, -9216, -3072, 3072, 9216, 15359, 21503},
125 {-23295, -16639, -9984, -3328, 3328, 9984, 16639, 23295},
126 {-25087, -17919, -10752, -3584, 3584, 10752, 17919, 25087},
127 {-26879, -19199, -11520, -3840, 3840, 11520, 19199, 26879},
128 {-28671, -20479, -12288, -4096, 4096, 12288, 20479, 28671}
129};
130
131static void apcm_dequant_add(GetBitContext *gb, int16_t *dst)
132{
133 int i;
134 int maxidx = get_bits(gb, 6);
135 const int16_t *tab = dequant_tab[maxidx];
136 for (i = 0; i < 13; i++)
137 dst[3*i] += tab[get_bits(gb, 3)];
138}
139
140static inline int gsm_mult(int a, int b)
141{
142 return (a * b + (1 << 14)) >> 15;
143}
144
145static const uint16_t long_term_gain_tab[4] = {
146 3277, 11469, 21299, 32767
147};
148
149static void long_term_synth(int16_t *dst, int lag, int gain_idx)
150{
151 int i;
152 const int16_t *src = dst - lag;
153 uint16_t gain = long_term_gain_tab[gain_idx];
154 for (i = 0; i < 40; i++)
155 dst[i] = gsm_mult(gain, src[i]);
156}
157
158static inline int decode_log_area(int coded, int factor, int offset)
159{
160 coded <<= 10;
161 coded -= offset;
162 return gsm_mult(coded, factor) << 1;
163}
164
165static av_noinline int get_rrp(int filtered)
166{
167 int abs = FFABS(filtered);
168 if (abs < 11059) abs <<= 1;
169 else if (abs < 20070) abs += 11059;
170 else abs = (abs >> 2) + 26112;
171 return filtered < 0 ? -abs : abs;
172}
173
174static int filter_value(int in, int rrp[8], int v[9])
175{
176 int i;
177 for (i = 7; i >= 0; i--) {
178 in -= gsm_mult(rrp[i], v[i]);
179 v[i + 1] = v[i] + gsm_mult(rrp[i], in);
180 }
181 v[0] = in;
182 return in;
183}
184
185static void short_term_synth(GSMContext *ctx, int16_t *dst, const int16_t *src)
186{
187 int i;
188 int rrp[8];
189 int *lar = ctx->lar[ctx->lar_idx];
190 int *lar_prev = ctx->lar[ctx->lar_idx ^ 1];
191 for (i = 0; i < 8; i++)
192 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar_prev[i] >> 1) + (lar[i] >> 2));
193 for (i = 0; i < 13; i++)
194 dst[i] = filter_value(src[i], rrp, ctx->v);
195
196 for (i = 0; i < 8; i++)
197 rrp[i] = get_rrp((lar_prev[i] >> 1) + (lar [i] >> 1));
198 for (i = 13; i < 27; i++)
199 dst[i] = filter_value(src[i], rrp, ctx->v);
200
201 for (i = 0; i < 8; i++)
202 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar [i] >> 1) + (lar[i] >> 2));
203 for (i = 27; i < 40; i++)
204 dst[i] = filter_value(src[i], rrp, ctx->v);
205
206 for (i = 0; i < 8; i++)
207 rrp[i] = get_rrp(lar[i]);
208 for (i = 40; i < 160; i++)
209 dst[i] = filter_value(src[i], rrp, ctx->v);
210
211 ctx->lar_idx ^= 1;
212}
213
214static int postprocess(int16_t *data, int msr)
215{
216 int i;
217 for (i = 0; i < 160; i++) {
218 msr = av_clip_int16(data[i] + gsm_mult(msr, 28180));
219 data[i] = av_clip_int16(msr << 1) & ~7;
220 }
221 return msr;
222}
223
224static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples,
225 GetBitContext *gb)
226{
227 GSMContext *ctx = avctx->priv_data;
228 int i;
229 int16_t *ref_dst = ctx->ref_buf + 120;
230 int *lar = ctx->lar[ctx->lar_idx];
231 lar[0] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
232 lar[1] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
233 lar[2] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) + 2048*2);
234 lar[3] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) - 2560*2);
235 lar[4] = decode_log_area(get_bits(gb, 4), 19223, (1 << 13) + 94*2);
236 lar[5] = decode_log_area(get_bits(gb, 4), 17476, (1 << 13) - 1792*2);
237 lar[6] = decode_log_area(get_bits(gb, 3), 31454, (1 << 12) - 341*2);
238 lar[7] = decode_log_area(get_bits(gb, 3), 29708, (1 << 12) - 1144*2);
239
240 for (i = 0; i < 4; i++) {
241 int lag = get_bits(gb, 7);
242 int gain_idx = get_bits(gb, 2);
243 int offset = get_bits(gb, 2);
244 lag = av_clip(lag, 40, 120);
245 long_term_synth(ref_dst, lag, gain_idx);
246 apcm_dequant_add(gb, ref_dst + offset);
247 ref_dst += 40;
248 }
249 memcpy(ctx->ref_buf, ctx->ref_buf + 160, 120 * sizeof(*ctx->ref_buf));
250 short_term_synth(ctx, samples, ctx->ref_buf + 120);
251 // for optimal speed this could be merged with short_term_synth,
252 // not done yet because it is a bit ugly
253 ctx->msr = postprocess(samples, ctx->msr);
254 return 0;
255}
256
257static int gsm_decode_frame(AVCodecContext *avctx, void *data,
258 int *data_size, AVPacket *avpkt)
259{
260 int res;
261 GetBitContext gb;
262 const uint8_t *buf = avpkt->data;
263 int buf_size = avpkt->size;
264 int16_t *samples = data;
265 int frame_bytes = 2 * avctx->frame_size;
266
267 if (*data_size < frame_bytes)
268 return -1;
269 *data_size = 0;
270 if(buf_size < avctx->block_align)
271 return AVERROR_INVALIDDATA;
272 init_get_bits(&gb, buf, buf_size * 8);
273
274 switch (avctx->codec_id) {
275 case CODEC_ID_GSM:
276 if (get_bits(&gb, 4) != 0xd)
277 av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
278 res = gsm_decode_block(avctx, samples, &gb);
279 if (res < 0)
280 return res;
281 break;
282 case CODEC_ID_GSM_MS:
283 res = gsm_decode_block(avctx, samples, &gb);
284 if (res < 0)
285 return res;
286 res = gsm_decode_block(avctx, samples + GSM_FRAME_SIZE, &gb);
287 if (res < 0)
288 return res;
289 }
290 *data_size = frame_bytes;
291 return avctx->block_align;
292}
293
294AVCodec gsm_decoder = {
295 "gsm",
296 AVMEDIA_TYPE_AUDIO,
297 CODEC_ID_GSM,
298 sizeof(GSMContext),
299 gsm_init,
300 NULL,
301 NULL,
302 gsm_decode_frame,
303 .long_name = NULL_IF_CONFIG_SMALL("GSM"),
304};
305
306AVCodec gsm_ms_decoder = {
307 "gsm_ms",
308 AVMEDIA_TYPE_AUDIO,
309 CODEC_ID_GSM_MS,
310 sizeof(GSMContext),
311 gsm_init,
312 NULL,
313 NULL,
314 gsm_decode_frame,
315 .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
316};