added pcm codecs
[libav.git] / libavcodec / pcm.c
CommitLineData
a96b68b7
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1/*
2 * PCM codecs
3 * Copyright (c) 2001 Gerard Lantau.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 */
19#include "avcodec.h"
20
21/* from g711.c by SUN microsystems (unrestricted use) */
22
23#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
24#define QUANT_MASK (0xf) /* Quantization field mask. */
25#define NSEGS (8) /* Number of A-law segments. */
26#define SEG_SHIFT (4) /* Left shift for segment number. */
27#define SEG_MASK (0x70) /* Segment field mask. */
28
29#define BIAS (0x84) /* Bias for linear code. */
30
31/*
32 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
33 *
34 */
35static int alaw2linear(unsigned char a_val)
36{
37 int t;
38 int seg;
39
40 a_val ^= 0x55;
41
42 t = (a_val & QUANT_MASK) << 4;
43 seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
44 switch (seg) {
45 case 0:
46 t += 8;
47 break;
48 case 1:
49 t += 0x108;
50 break;
51 default:
52 t += 0x108;
53 t <<= seg - 1;
54 }
55 return ((a_val & SIGN_BIT) ? t : -t);
56}
57
58static int ulaw2linear(unsigned char u_val)
59{
60 int t;
61
62 /* Complement to obtain normal u-law value. */
63 u_val = ~u_val;
64
65 /*
66 * Extract and bias the quantization bits. Then
67 * shift up by the segment number and subtract out the bias.
68 */
69 t = ((u_val & QUANT_MASK) << 3) + BIAS;
70 t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
71
72 return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
73}
74
75/* 16384 entries per table */
76static UINT8 *linear_to_alaw = NULL;
77static int linear_to_alaw_ref = 0;
78
79static UINT8 *linear_to_ulaw = NULL;
80static int linear_to_ulaw_ref = 0;
81
82static void build_xlaw_table(UINT8 *linear_to_xlaw,
83 int (*xlaw2linear)(unsigned char),
84 int mask)
85{
86 int i, j, v, v1, v2;
87
88 j = 0;
89 for(i=0;i<128;i++) {
90 if (i != 127) {
91 v1 = xlaw2linear(i ^ mask);
92 v2 = xlaw2linear((i + 1) ^ mask);
93 v = (v1 + v2 + 4) >> 3;
94 } else {
95 v = 8192;
96 }
97 for(;j<v;j++) {
98 linear_to_xlaw[8192 + j] = (i ^ mask);
99 if (j > 0)
100 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
101 }
102 }
103 linear_to_xlaw[0] = linear_to_xlaw[1];
104}
105
106static int encode_init(AVCodecContext *avctx)
107{
108 avctx->frame_size = 1;
109 switch(avctx->codec->id) {
110 case CODEC_ID_PCM_ALAW:
111 if (linear_to_alaw_ref == 0) {
112 linear_to_alaw = malloc(16384);
113 if (!linear_to_alaw)
114 return -1;
115 build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
116 }
117 linear_to_alaw_ref++;
118 break;
119 case CODEC_ID_PCM_MULAW:
120 if (linear_to_ulaw_ref == 0) {
121 linear_to_ulaw = malloc(16384);
122 if (!linear_to_ulaw)
123 return -1;
124 build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
125 }
126 linear_to_ulaw_ref++;
127 break;
128 default:
129 break;
130 }
131 return 0;
132}
133
134static int encode_close(AVCodecContext *avctx)
135{
136 switch(avctx->codec->id) {
137 case CODEC_ID_PCM_ALAW:
138 if (--linear_to_alaw_ref == 0)
139 free(linear_to_alaw);
140 break;
141 case CODEC_ID_PCM_MULAW:
142 if (--linear_to_ulaw_ref == 0)
143 free(linear_to_ulaw);
144 break;
145 default:
146 /* nothing to free */
147 break;
148 }
149 return 0;
150}
151
152static int encode_frame(AVCodecContext *avctx,
153 unsigned char *frame, int buf_size, void *data)
154{
155 int n, sample_size, v;
156 short *samples;
157 unsigned char *dst;
158
159 switch(avctx->codec->id) {
160 case CODEC_ID_PCM_S16LE:
161 case CODEC_ID_PCM_S16BE:
162 case CODEC_ID_PCM_U16LE:
163 case CODEC_ID_PCM_U16BE:
164 sample_size = 2;
165 break;
166 default:
167 sample_size = 1;
168 break;
169 }
170 n = buf_size / sample_size;
171 samples = data;
172 dst = frame;
173
174 switch(avctx->codec->id) {
175 case CODEC_ID_PCM_S16LE:
176 for(;n>0;n--) {
177 v = *samples++;
178 dst[0] = v & 0xff;
179 dst[1] = v >> 8;
180 dst += 2;
181 }
182 break;
183 case CODEC_ID_PCM_S16BE:
184 for(;n>0;n--) {
185 v = *samples++;
186 dst[0] = v >> 8;
187 dst[1] = v;
188 dst += 2;
189 }
190 break;
191 case CODEC_ID_PCM_U16LE:
192 for(;n>0;n--) {
193 v = *samples++;
194 v += 0x8000;
195 dst[0] = v & 0xff;
196 dst[1] = v >> 8;
197 dst += 2;
198 }
199 break;
200 case CODEC_ID_PCM_U16BE:
201 for(;n>0;n--) {
202 v = *samples++;
203 v += 0x8000;
204 dst[0] = v >> 8;
205 dst[1] = v;
206 dst += 2;
207 }
208 break;
209 case CODEC_ID_PCM_S8:
210 for(;n>0;n--) {
211 v = *samples++;
212 dst[0] = (v + 128) >> 8;
213 dst++;
214 }
215 break;
216 case CODEC_ID_PCM_U8:
217 for(;n>0;n--) {
218 v = *samples++;
219 dst[0] = ((v + 128) >> 8) + 128;
220 dst++;
221 }
222 break;
223 case CODEC_ID_PCM_ALAW:
224 for(;n>0;n--) {
225 v = *samples++;
226 dst[0] = linear_to_alaw[(v + 32768) >> 2];
227 dst++;
228 }
229 break;
230 case CODEC_ID_PCM_MULAW:
231 for(;n>0;n--) {
232 v = *samples++;
233 dst[0] = linear_to_ulaw[(v + 32768) >> 2];
234 dst++;
235 }
236 break;
237 default:
238 return -1;
239 }
240 return dst - frame;
241}
242
243typedef struct PCMDecode {
244 short table[256];
245} PCMDecode;
246
247static int decode_init(AVCodecContext * avctx)
248{
249 PCMDecode *s = avctx->priv_data;
250 int i;
251
252 switch(avctx->codec->id) {
253 case CODEC_ID_PCM_ALAW:
254 for(i=0;i<256;i++)
255 s->table[i] = alaw2linear(i);
256 break;
257 case CODEC_ID_PCM_MULAW:
258 for(i=0;i<256;i++)
259 s->table[i] = ulaw2linear(i);
260 break;
261 default:
262 break;
263 }
264 return 0;
265}
266
267static int decode_frame(AVCodecContext *avctx,
268 void *data, int *data_size,
269 UINT8 *buf, int buf_size)
270{
271 PCMDecode *s = avctx->priv_data;
272 int n;
273 short *samples;
274 UINT8 *src;
275
276 samples = data;
277 src = buf;
278
279 switch(avctx->codec->id) {
280 case CODEC_ID_PCM_S16LE:
281 n = buf_size >> 1;
282 for(;n>0;n--) {
283 *samples++ = src[0] | (src[1] << 8);
284 src += 2;
285 }
286 break;
287 case CODEC_ID_PCM_S16BE:
288 n = buf_size >> 1;
289 for(;n>0;n--) {
290 *samples++ = (src[0] << 8) | src[1];
291 src += 2;
292 }
293 break;
294 case CODEC_ID_PCM_U16LE:
295 n = buf_size >> 1;
296 for(;n>0;n--) {
297 *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
298 src += 2;
299 }
300 break;
301 case CODEC_ID_PCM_U16BE:
302 n = buf_size >> 1;
303 for(;n>0;n--) {
304 *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
305 src += 2;
306 }
307 break;
308 case CODEC_ID_PCM_S8:
309 n = buf_size;
310 for(;n>0;n--) {
311 *samples++ = src[0] << 8;
312 src++;
313 }
314 break;
315 case CODEC_ID_PCM_U8:
316 n = buf_size;
317 for(;n>0;n--) {
318 *samples++ = ((int)src[0] - 128) << 8;
319 src++;
320 }
321 break;
322 case CODEC_ID_PCM_ALAW:
323 case CODEC_ID_PCM_MULAW:
324 n = buf_size;
325 for(;n>0;n--) {
326 *samples++ = s->table[src[0]];
327 src++;
328 }
329 break;
330 default:
331 *data_size = 0;
332 return -1;
333 }
334 *data_size = (UINT8 *)samples - (UINT8 *)data;
335 return src - buf;
336}
337
338#define PCM_CODEC(id, name) \
339AVCodec name ## _encoder = { \
340 #name, \
341 CODEC_TYPE_AUDIO, \
342 id, \
343 0, \
344 encode_init, \
345 encode_frame, \
346 encode_close, \
347 NULL, \
348}; \
349AVCodec name ## _decoder = { \
350 #name, \
351 CODEC_TYPE_AUDIO, \
352 id, \
353 sizeof(PCMDecode), \
354 decode_init, \
355 NULL, \
356 NULL, \
357 decode_frame, \
358};
359
360PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
361PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
362PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
363PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
364PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
365PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
366PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
367PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);