remove weird offsets
[libav.git] / libavcodec / pcm.c
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1/*
2 * PCM codecs
ff4ec49e 3 * Copyright (c) 2001 Fabrice Bellard.
a96b68b7 4 *
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5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
a96b68b7 9 *
ff4ec49e 10 * This library is distributed in the hope that it will be useful,
a96b68b7 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
a96b68b7 14 *
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15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
a96b68b7 18 */
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19
20/**
21 * @file pcm.c
22 * PCM codecs
23 */
24
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25#include "avcodec.h"
26
27/* from g711.c by SUN microsystems (unrestricted use) */
28
29#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
30#define QUANT_MASK (0xf) /* Quantization field mask. */
31#define NSEGS (8) /* Number of A-law segments. */
32#define SEG_SHIFT (4) /* Left shift for segment number. */
33#define SEG_MASK (0x70) /* Segment field mask. */
34
35#define BIAS (0x84) /* Bias for linear code. */
36
37/*
38 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
39 *
40 */
41static int alaw2linear(unsigned char a_val)
42{
43 int t;
44 int seg;
45
46 a_val ^= 0x55;
47
cd1f22f9 48 t = a_val & QUANT_MASK;
a96b68b7 49 seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
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50 if(seg) t= (t + t + 1 + 32) << (seg + 2);
51 else t= (t + t + 1 ) << 3;
52
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53 return ((a_val & SIGN_BIT) ? t : -t);
54}
55
56static int ulaw2linear(unsigned char u_val)
57{
58 int t;
59
60 /* Complement to obtain normal u-law value. */
61 u_val = ~u_val;
62
63 /*
64 * Extract and bias the quantization bits. Then
65 * shift up by the segment number and subtract out the bias.
66 */
67 t = ((u_val & QUANT_MASK) << 3) + BIAS;
68 t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
69
70 return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
71}
72
73/* 16384 entries per table */
0c1a9eda 74static uint8_t *linear_to_alaw = NULL;
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75static int linear_to_alaw_ref = 0;
76
0c1a9eda 77static uint8_t *linear_to_ulaw = NULL;
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78static int linear_to_ulaw_ref = 0;
79
0c1a9eda 80static void build_xlaw_table(uint8_t *linear_to_xlaw,
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81 int (*xlaw2linear)(unsigned char),
82 int mask)
83{
84 int i, j, v, v1, v2;
85
86 j = 0;
87 for(i=0;i<128;i++) {
88 if (i != 127) {
89 v1 = xlaw2linear(i ^ mask);
90 v2 = xlaw2linear((i + 1) ^ mask);
91 v = (v1 + v2 + 4) >> 3;
92 } else {
93 v = 8192;
94 }
95 for(;j<v;j++) {
96 linear_to_xlaw[8192 + j] = (i ^ mask);
97 if (j > 0)
98 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
99 }
100 }
101 linear_to_xlaw[0] = linear_to_xlaw[1];
102}
103
cd4af68a 104static int pcm_encode_init(AVCodecContext *avctx)
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105{
106 avctx->frame_size = 1;
107 switch(avctx->codec->id) {
108 case CODEC_ID_PCM_ALAW:
109 if (linear_to_alaw_ref == 0) {
6000abfa 110 linear_to_alaw = av_malloc(16384);
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111 if (!linear_to_alaw)
112 return -1;
113 build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
114 }
115 linear_to_alaw_ref++;
116 break;
117 case CODEC_ID_PCM_MULAW:
118 if (linear_to_ulaw_ref == 0) {
6000abfa 119 linear_to_ulaw = av_malloc(16384);
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120 if (!linear_to_ulaw)
121 return -1;
122 build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
123 }
124 linear_to_ulaw_ref++;
125 break;
126 default:
127 break;
128 }
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129
130 avctx->coded_frame= avcodec_alloc_frame();
131 avctx->coded_frame->key_frame= 1;
132
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133 return 0;
134}
135
cd4af68a 136static int pcm_encode_close(AVCodecContext *avctx)
a96b68b7 137{
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138 av_freep(&avctx->coded_frame);
139
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140 switch(avctx->codec->id) {
141 case CODEC_ID_PCM_ALAW:
142 if (--linear_to_alaw_ref == 0)
6000abfa 143 av_free(linear_to_alaw);
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144 break;
145 case CODEC_ID_PCM_MULAW:
146 if (--linear_to_ulaw_ref == 0)
6000abfa 147 av_free(linear_to_ulaw);
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148 break;
149 default:
150 /* nothing to free */
151 break;
152 }
153 return 0;
154}
155
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156static int pcm_encode_frame(AVCodecContext *avctx,
157 unsigned char *frame, int buf_size, void *data)
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158{
159 int n, sample_size, v;
160 short *samples;
161 unsigned char *dst;
162
163 switch(avctx->codec->id) {
164 case CODEC_ID_PCM_S16LE:
165 case CODEC_ID_PCM_S16BE:
166 case CODEC_ID_PCM_U16LE:
167 case CODEC_ID_PCM_U16BE:
168 sample_size = 2;
169 break;
170 default:
171 sample_size = 1;
172 break;
173 }
174 n = buf_size / sample_size;
175 samples = data;
176 dst = frame;
177
178 switch(avctx->codec->id) {
179 case CODEC_ID_PCM_S16LE:
180 for(;n>0;n--) {
181 v = *samples++;
182 dst[0] = v & 0xff;
183 dst[1] = v >> 8;
184 dst += 2;
185 }
186 break;
187 case CODEC_ID_PCM_S16BE:
188 for(;n>0;n--) {
189 v = *samples++;
190 dst[0] = v >> 8;
191 dst[1] = v;
192 dst += 2;
193 }
194 break;
195 case CODEC_ID_PCM_U16LE:
196 for(;n>0;n--) {
197 v = *samples++;
198 v += 0x8000;
199 dst[0] = v & 0xff;
200 dst[1] = v >> 8;
201 dst += 2;
202 }
203 break;
204 case CODEC_ID_PCM_U16BE:
205 for(;n>0;n--) {
206 v = *samples++;
207 v += 0x8000;
208 dst[0] = v >> 8;
209 dst[1] = v;
210 dst += 2;
211 }
212 break;
213 case CODEC_ID_PCM_S8:
214 for(;n>0;n--) {
215 v = *samples++;
0eaec105 216 dst[0] = v >> 8;
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217 dst++;
218 }
219 break;
220 case CODEC_ID_PCM_U8:
221 for(;n>0;n--) {
222 v = *samples++;
0eaec105 223 dst[0] = (v >> 8) + 128;
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224 dst++;
225 }
226 break;
227 case CODEC_ID_PCM_ALAW:
228 for(;n>0;n--) {
229 v = *samples++;
230 dst[0] = linear_to_alaw[(v + 32768) >> 2];
231 dst++;
232 }
233 break;
234 case CODEC_ID_PCM_MULAW:
235 for(;n>0;n--) {
236 v = *samples++;
237 dst[0] = linear_to_ulaw[(v + 32768) >> 2];
238 dst++;
239 }
240 break;
241 default:
242 return -1;
243 }
13a0314f 244 //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
4c3d2e5f 245
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246 return dst - frame;
247}
248
249typedef struct PCMDecode {
250 short table[256];
251} PCMDecode;
252
cd4af68a 253static int pcm_decode_init(AVCodecContext * avctx)
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254{
255 PCMDecode *s = avctx->priv_data;
256 int i;
257
258 switch(avctx->codec->id) {
259 case CODEC_ID_PCM_ALAW:
260 for(i=0;i<256;i++)
261 s->table[i] = alaw2linear(i);
262 break;
263 case CODEC_ID_PCM_MULAW:
264 for(i=0;i<256;i++)
265 s->table[i] = ulaw2linear(i);
266 break;
267 default:
268 break;
269 }
270 return 0;
271}
272
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273static int pcm_decode_frame(AVCodecContext *avctx,
274 void *data, int *data_size,
0c1a9eda 275 uint8_t *buf, int buf_size)
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276{
277 PCMDecode *s = avctx->priv_data;
278 int n;
279 short *samples;
0c1a9eda 280 uint8_t *src;
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281
282 samples = data;
283 src = buf;
284
285 switch(avctx->codec->id) {
286 case CODEC_ID_PCM_S16LE:
287 n = buf_size >> 1;
288 for(;n>0;n--) {
289 *samples++ = src[0] | (src[1] << 8);
290 src += 2;
291 }
292 break;
293 case CODEC_ID_PCM_S16BE:
294 n = buf_size >> 1;
295 for(;n>0;n--) {
296 *samples++ = (src[0] << 8) | src[1];
297 src += 2;
298 }
299 break;
300 case CODEC_ID_PCM_U16LE:
301 n = buf_size >> 1;
302 for(;n>0;n--) {
303 *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
304 src += 2;
305 }
306 break;
307 case CODEC_ID_PCM_U16BE:
308 n = buf_size >> 1;
309 for(;n>0;n--) {
310 *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
311 src += 2;
312 }
313 break;
314 case CODEC_ID_PCM_S8:
315 n = buf_size;
316 for(;n>0;n--) {
317 *samples++ = src[0] << 8;
318 src++;
319 }
320 break;
321 case CODEC_ID_PCM_U8:
322 n = buf_size;
323 for(;n>0;n--) {
324 *samples++ = ((int)src[0] - 128) << 8;
325 src++;
326 }
327 break;
328 case CODEC_ID_PCM_ALAW:
329 case CODEC_ID_PCM_MULAW:
330 n = buf_size;
331 for(;n>0;n--) {
332 *samples++ = s->table[src[0]];
333 src++;
334 }
335 break;
336 default:
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337 return -1;
338 }
0c1a9eda 339 *data_size = (uint8_t *)samples - (uint8_t *)data;
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340 return src - buf;
341}
342
343#define PCM_CODEC(id, name) \
344AVCodec name ## _encoder = { \
345 #name, \
346 CODEC_TYPE_AUDIO, \
347 id, \
348 0, \
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349 pcm_encode_init, \
350 pcm_encode_frame, \
351 pcm_encode_close, \
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352 NULL, \
353}; \
354AVCodec name ## _decoder = { \
355 #name, \
356 CODEC_TYPE_AUDIO, \
357 id, \
358 sizeof(PCMDecode), \
cd4af68a 359 pcm_decode_init, \
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360 NULL, \
361 NULL, \
cd4af68a 362 pcm_decode_frame, \
ef9f7306 363}
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364
365PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
366PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
367PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
368PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
369PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
370PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
371PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
372PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
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373
374#undef PCM_CODEC