Avoid cast of double nan to int.
[libav.git] / libavcodec / gsmdec.c
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b576934d
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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 {
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37 // Contains first 120 elements from the previous frame
38 // (used by long_term_synth according to the "lag"),
39 // then in the following 160 elements the current
40 // frame is constructed.
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41 int16_t ref_buf[280];
42 int v[9];
43 int lar[2][8];
44 int lar_idx;
45 int msr;
46} GSMContext;
47
48static av_cold int gsm_init(AVCodecContext *avctx)
49{
50 avctx->channels = 1;
51 if (!avctx->sample_rate)
52 avctx->sample_rate = 8000;
53 avctx->sample_fmt = SAMPLE_FMT_S16;
54
55 switch (avctx->codec_id) {
56 case CODEC_ID_GSM:
57 avctx->frame_size = GSM_FRAME_SIZE;
58 avctx->block_align = GSM_BLOCK_SIZE;
59 break;
60 case CODEC_ID_GSM_MS:
61 avctx->frame_size = 2 * GSM_FRAME_SIZE;
62 avctx->block_align = GSM_MS_BLOCK_SIZE;
63 }
64
65 return 0;
66}
67
68static const int16_t dequant_tab[64][8] = {
69 { -28, -20, -12, -4, 4, 12, 20, 28},
70 { -56, -40, -24, -8, 8, 24, 40, 56},
71 { -84, -60, -36, -12, 12, 36, 60, 84},
72 { -112, -80, -48, -16, 16, 48, 80, 112},
73 { -140, -100, -60, -20, 20, 60, 100, 140},
74 { -168, -120, -72, -24, 24, 72, 120, 168},
75 { -196, -140, -84, -28, 28, 84, 140, 196},
76 { -224, -160, -96, -32, 32, 96, 160, 224},
77 { -252, -180, -108, -36, 36, 108, 180, 252},
78 { -280, -200, -120, -40, 40, 120, 200, 280},
79 { -308, -220, -132, -44, 44, 132, 220, 308},
80 { -336, -240, -144, -48, 48, 144, 240, 336},
81 { -364, -260, -156, -52, 52, 156, 260, 364},
82 { -392, -280, -168, -56, 56, 168, 280, 392},
83 { -420, -300, -180, -60, 60, 180, 300, 420},
84 { -448, -320, -192, -64, 64, 192, 320, 448},
85 { -504, -360, -216, -72, 72, 216, 360, 504},
86 { -560, -400, -240, -80, 80, 240, 400, 560},
87 { -616, -440, -264, -88, 88, 264, 440, 616},
88 { -672, -480, -288, -96, 96, 288, 480, 672},
89 { -728, -520, -312, -104, 104, 312, 520, 728},
90 { -784, -560, -336, -112, 112, 336, 560, 784},
91 { -840, -600, -360, -120, 120, 360, 600, 840},
92 { -896, -640, -384, -128, 128, 384, 640, 896},
93 { -1008, -720, -432, -144, 144, 432, 720, 1008},
94 { -1120, -800, -480, -160, 160, 480, 800, 1120},
95 { -1232, -880, -528, -176, 176, 528, 880, 1232},
96 { -1344, -960, -576, -192, 192, 576, 960, 1344},
97 { -1456, -1040, -624, -208, 208, 624, 1040, 1456},
98 { -1568, -1120, -672, -224, 224, 672, 1120, 1568},
99 { -1680, -1200, -720, -240, 240, 720, 1200, 1680},
100 { -1792, -1280, -768, -256, 256, 768, 1280, 1792},
101 { -2016, -1440, -864, -288, 288, 864, 1440, 2016},
102 { -2240, -1600, -960, -320, 320, 960, 1600, 2240},
103 { -2464, -1760, -1056, -352, 352, 1056, 1760, 2464},
104 { -2688, -1920, -1152, -384, 384, 1152, 1920, 2688},
105 { -2912, -2080, -1248, -416, 416, 1248, 2080, 2912},
106 { -3136, -2240, -1344, -448, 448, 1344, 2240, 3136},
107 { -3360, -2400, -1440, -480, 480, 1440, 2400, 3360},
108 { -3584, -2560, -1536, -512, 512, 1536, 2560, 3584},
109 { -4032, -2880, -1728, -576, 576, 1728, 2880, 4032},
110 { -4480, -3200, -1920, -640, 640, 1920, 3200, 4480},
111 { -4928, -3520, -2112, -704, 704, 2112, 3520, 4928},
112 { -5376, -3840, -2304, -768, 768, 2304, 3840, 5376},
113 { -5824, -4160, -2496, -832, 832, 2496, 4160, 5824},
114 { -6272, -4480, -2688, -896, 896, 2688, 4480, 6272},
115 { -6720, -4800, -2880, -960, 960, 2880, 4800, 6720},
116 { -7168, -5120, -3072, -1024, 1024, 3072, 5120, 7168},
117 { -8063, -5759, -3456, -1152, 1152, 3456, 5760, 8064},
118 { -8959, -6399, -3840, -1280, 1280, 3840, 6400, 8960},
119 { -9855, -7039, -4224, -1408, 1408, 4224, 7040, 9856},
120 {-10751, -7679, -4608, -1536, 1536, 4608, 7680, 10752},
121 {-11647, -8319, -4992, -1664, 1664, 4992, 8320, 11648},
122 {-12543, -8959, -5376, -1792, 1792, 5376, 8960, 12544},
123 {-13439, -9599, -5760, -1920, 1920, 5760, 9600, 13440},
124 {-14335, -10239, -6144, -2048, 2048, 6144, 10240, 14336},
125 {-16127, -11519, -6912, -2304, 2304, 6912, 11519, 16127},
126 {-17919, -12799, -7680, -2560, 2560, 7680, 12799, 17919},
127 {-19711, -14079, -8448, -2816, 2816, 8448, 14079, 19711},
128 {-21503, -15359, -9216, -3072, 3072, 9216, 15359, 21503},
129 {-23295, -16639, -9984, -3328, 3328, 9984, 16639, 23295},
130 {-25087, -17919, -10752, -3584, 3584, 10752, 17919, 25087},
131 {-26879, -19199, -11520, -3840, 3840, 11520, 19199, 26879},
132 {-28671, -20479, -12288, -4096, 4096, 12288, 20479, 28671}
133};
134
135static void apcm_dequant_add(GetBitContext *gb, int16_t *dst)
136{
137 int i;
138 int maxidx = get_bits(gb, 6);
139 const int16_t *tab = dequant_tab[maxidx];
140 for (i = 0; i < 13; i++)
141 dst[3*i] += tab[get_bits(gb, 3)];
142}
143
144static inline int gsm_mult(int a, int b)
145{
146 return (a * b + (1 << 14)) >> 15;
147}
148
149static const uint16_t long_term_gain_tab[4] = {
150 3277, 11469, 21299, 32767
151};
152
153static void long_term_synth(int16_t *dst, int lag, int gain_idx)
154{
155 int i;
156 const int16_t *src = dst - lag;
157 uint16_t gain = long_term_gain_tab[gain_idx];
158 for (i = 0; i < 40; i++)
159 dst[i] = gsm_mult(gain, src[i]);
160}
161
162static inline int decode_log_area(int coded, int factor, int offset)
163{
164 coded <<= 10;
165 coded -= offset;
166 return gsm_mult(coded, factor) << 1;
167}
168
169static av_noinline int get_rrp(int filtered)
170{
171 int abs = FFABS(filtered);
172 if (abs < 11059) abs <<= 1;
173 else if (abs < 20070) abs += 11059;
174 else abs = (abs >> 2) + 26112;
175 return filtered < 0 ? -abs : abs;
176}
177
178static int filter_value(int in, int rrp[8], int v[9])
179{
180 int i;
181 for (i = 7; i >= 0; i--) {
182 in -= gsm_mult(rrp[i], v[i]);
183 v[i + 1] = v[i] + gsm_mult(rrp[i], in);
184 }
185 v[0] = in;
186 return in;
187}
188
189static void short_term_synth(GSMContext *ctx, int16_t *dst, const int16_t *src)
190{
191 int i;
192 int rrp[8];
193 int *lar = ctx->lar[ctx->lar_idx];
194 int *lar_prev = ctx->lar[ctx->lar_idx ^ 1];
195 for (i = 0; i < 8; i++)
196 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar_prev[i] >> 1) + (lar[i] >> 2));
197 for (i = 0; i < 13; i++)
198 dst[i] = filter_value(src[i], rrp, ctx->v);
199
200 for (i = 0; i < 8; i++)
201 rrp[i] = get_rrp((lar_prev[i] >> 1) + (lar [i] >> 1));
202 for (i = 13; i < 27; i++)
203 dst[i] = filter_value(src[i], rrp, ctx->v);
204
205 for (i = 0; i < 8; i++)
206 rrp[i] = get_rrp((lar_prev[i] >> 2) + (lar [i] >> 1) + (lar[i] >> 2));
207 for (i = 27; i < 40; i++)
208 dst[i] = filter_value(src[i], rrp, ctx->v);
209
210 for (i = 0; i < 8; i++)
211 rrp[i] = get_rrp(lar[i]);
212 for (i = 40; i < 160; i++)
213 dst[i] = filter_value(src[i], rrp, ctx->v);
214
215 ctx->lar_idx ^= 1;
216}
217
218static int postprocess(int16_t *data, int msr)
219{
220 int i;
221 for (i = 0; i < 160; i++) {
222 msr = av_clip_int16(data[i] + gsm_mult(msr, 28180));
223 data[i] = av_clip_int16(msr << 1) & ~7;
224 }
225 return msr;
226}
227
228static int gsm_decode_block(AVCodecContext *avctx, int16_t *samples,
229 GetBitContext *gb)
230{
231 GSMContext *ctx = avctx->priv_data;
232 int i;
233 int16_t *ref_dst = ctx->ref_buf + 120;
234 int *lar = ctx->lar[ctx->lar_idx];
235 lar[0] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
236 lar[1] = decode_log_area(get_bits(gb, 6), 13107, 1 << 15);
237 lar[2] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) + 2048*2);
238 lar[3] = decode_log_area(get_bits(gb, 5), 13107, (1 << 14) - 2560*2);
239 lar[4] = decode_log_area(get_bits(gb, 4), 19223, (1 << 13) + 94*2);
240 lar[5] = decode_log_area(get_bits(gb, 4), 17476, (1 << 13) - 1792*2);
241 lar[6] = decode_log_area(get_bits(gb, 3), 31454, (1 << 12) - 341*2);
242 lar[7] = decode_log_area(get_bits(gb, 3), 29708, (1 << 12) - 1144*2);
243
244 for (i = 0; i < 4; i++) {
245 int lag = get_bits(gb, 7);
246 int gain_idx = get_bits(gb, 2);
247 int offset = get_bits(gb, 2);
248 lag = av_clip(lag, 40, 120);
249 long_term_synth(ref_dst, lag, gain_idx);
250 apcm_dequant_add(gb, ref_dst + offset);
251 ref_dst += 40;
252 }
253 memcpy(ctx->ref_buf, ctx->ref_buf + 160, 120 * sizeof(*ctx->ref_buf));
254 short_term_synth(ctx, samples, ctx->ref_buf + 120);
255 // for optimal speed this could be merged with short_term_synth,
256 // not done yet because it is a bit ugly
257 ctx->msr = postprocess(samples, ctx->msr);
258 return 0;
259}
260
261static int gsm_decode_frame(AVCodecContext *avctx, void *data,
262 int *data_size, AVPacket *avpkt)
263{
264 int res;
265 GetBitContext gb;
266 const uint8_t *buf = avpkt->data;
267 int buf_size = avpkt->size;
268 int16_t *samples = data;
269 int frame_bytes = 2 * avctx->frame_size;
270
271 if (*data_size < frame_bytes)
272 return -1;
273 *data_size = 0;
274 if(buf_size < avctx->block_align)
275 return AVERROR_INVALIDDATA;
276 init_get_bits(&gb, buf, buf_size * 8);
277
278 switch (avctx->codec_id) {
279 case CODEC_ID_GSM:
280 if (get_bits(&gb, 4) != 0xd)
281 av_log(avctx, AV_LOG_WARNING, "Missing GSM magic!\n");
282 res = gsm_decode_block(avctx, samples, &gb);
283 if (res < 0)
284 return res;
285 break;
286 case CODEC_ID_GSM_MS:
287 res = gsm_decode_block(avctx, samples, &gb);
288 if (res < 0)
289 return res;
290 res = gsm_decode_block(avctx, samples + GSM_FRAME_SIZE, &gb);
291 if (res < 0)
292 return res;
293 }
294 *data_size = frame_bytes;
295 return avctx->block_align;
296}
297
298AVCodec gsm_decoder = {
299 "gsm",
300 AVMEDIA_TYPE_AUDIO,
301 CODEC_ID_GSM,
302 sizeof(GSMContext),
303 gsm_init,
304 NULL,
305 NULL,
306 gsm_decode_frame,
307 .long_name = NULL_IF_CONFIG_SMALL("GSM"),
308};
309
310AVCodec gsm_ms_decoder = {
311 "gsm_ms",
312 AVMEDIA_TYPE_AUDIO,
313 CODEC_ID_GSM_MS,
314 sizeof(GSMContext),
315 gsm_init,
316 NULL,
317 NULL,
318 gsm_decode_frame,
319 .long_name = NULL_IF_CONFIG_SMALL("GSM Microsoft variant"),
320};