Statistics
| Branch: | Revision:

ffmpeg / libavcodec / pcm.c @ 5a2f421a

History | View | Annotate | Download (14.2 KB)

1
/*
2
 * PCM codecs
3
 * Copyright (c) 2001 Fabrice Bellard.
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 pcm.c
24
 * PCM codecs
25
 */
26

    
27
#include "avcodec.h"
28
#include "bitstream.h" // for ff_reverse
29
#include "bytestream.h"
30

    
31
/* from g711.c by SUN microsystems (unrestricted use) */
32

    
33
#define         SIGN_BIT        (0x80)      /* Sign bit for a A-law byte. */
34
#define         QUANT_MASK      (0xf)       /* Quantization field mask. */
35
#define         NSEGS           (8)         /* Number of A-law segments. */
36
#define         SEG_SHIFT       (4)         /* Left shift for segment number. */
37
#define         SEG_MASK        (0x70)      /* Segment field mask. */
38

    
39
#define         BIAS            (0x84)      /* Bias for linear code. */
40

    
41
/*
42
 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
43
 *
44
 */
45
static int alaw2linear(unsigned char a_val)
46
{
47
        int t;
48
        int seg;
49

    
50
        a_val ^= 0x55;
51

    
52
        t = a_val & QUANT_MASK;
53
        seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
54
        if(seg) t= (t + t + 1 + 32) << (seg + 2);
55
        else    t= (t + t + 1     ) << 3;
56

    
57
        return ((a_val & SIGN_BIT) ? t : -t);
58
}
59

    
60
static int ulaw2linear(unsigned char u_val)
61
{
62
        int t;
63

    
64
        /* Complement to obtain normal u-law value. */
65
        u_val = ~u_val;
66

    
67
        /*
68
         * Extract and bias the quantization bits. Then
69
         * shift up by the segment number and subtract out the bias.
70
         */
71
        t = ((u_val & QUANT_MASK) << 3) + BIAS;
72
        t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
73

    
74
        return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
75
}
76

    
77
/* 16384 entries per table */
78
static uint8_t linear_to_alaw[16384];
79
static uint8_t linear_to_ulaw[16384];
80

    
81
static void build_xlaw_table(uint8_t *linear_to_xlaw,
82
                             int (*xlaw2linear)(unsigned char),
83
                             int mask)
84
{
85
    int i, j, v, v1, v2;
86

    
87
    j = 0;
88
    for(i=0;i<128;i++) {
89
        if (i != 127) {
90
            v1 = xlaw2linear(i ^ mask);
91
            v2 = xlaw2linear((i + 1) ^ mask);
92
            v = (v1 + v2 + 4) >> 3;
93
        } else {
94
            v = 8192;
95
        }
96
        for(;j<v;j++) {
97
            linear_to_xlaw[8192 + j] = (i ^ mask);
98
            if (j > 0)
99
                linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
100
        }
101
    }
102
    linear_to_xlaw[0] = linear_to_xlaw[1];
103
}
104

    
105
static int pcm_encode_init(AVCodecContext *avctx)
106
{
107
    avctx->frame_size = 1;
108
    switch(avctx->codec->id) {
109
    case CODEC_ID_PCM_ALAW:
110
        build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
111
        break;
112
    case CODEC_ID_PCM_MULAW:
113
        build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
114
        break;
115
    default:
116
        break;
117
    }
118

    
119
    switch(avctx->codec->id) {
120
    case CODEC_ID_PCM_S32LE:
121
    case CODEC_ID_PCM_S32BE:
122
    case CODEC_ID_PCM_U32LE:
123
    case CODEC_ID_PCM_U32BE:
124
        avctx->block_align = 4 * avctx->channels;
125
        break;
126
    case CODEC_ID_PCM_S24LE:
127
    case CODEC_ID_PCM_S24BE:
128
    case CODEC_ID_PCM_U24LE:
129
    case CODEC_ID_PCM_U24BE:
130
    case CODEC_ID_PCM_S24DAUD:
131
        avctx->block_align = 3 * avctx->channels;
132
        break;
133
    case CODEC_ID_PCM_S16LE:
134
    case CODEC_ID_PCM_S16BE:
135
    case CODEC_ID_PCM_U16LE:
136
    case CODEC_ID_PCM_U16BE:
137
        avctx->block_align = 2 * avctx->channels;
138
        break;
139
    case CODEC_ID_PCM_S8:
140
    case CODEC_ID_PCM_U8:
141
    case CODEC_ID_PCM_MULAW:
142
    case CODEC_ID_PCM_ALAW:
143
        avctx->block_align = avctx->channels;
144
        break;
145
    default:
146
        break;
147
    }
148

    
149
    avctx->coded_frame= avcodec_alloc_frame();
150
    avctx->coded_frame->key_frame= 1;
151

    
152
    return 0;
153
}
154

    
155
static int pcm_encode_close(AVCodecContext *avctx)
156
{
157
    av_freep(&avctx->coded_frame);
158

    
159
    return 0;
160
}
161

    
162
/**
163
 * \brief convert samples from 16 bit
164
 * \param bps byte per sample for the destination format, must be >= 2
165
 * \param le 0 for big-, 1 for little-endian
166
 * \param us 0 for signed, 1 for unsigned output
167
 * \param samples input samples
168
 * \param dst output samples
169
 * \param n number of samples in samples buffer.
170
 */
171
static inline void encode_from16(int bps, int le, int us,
172
                               short **samples, uint8_t **dst, int n) {
173
    int usum = us ? 0x8000 : 0;
174
    if (bps > 2)
175
        memset(*dst, 0, n * bps);
176
    if (le) *dst += bps - 2;
177
    for(;n>0;n--) {
178
        register int v = *(*samples)++;
179
        v += usum;
180
        if (le) AV_WL16(*dst, v);
181
        else    AV_WB16(*dst, v);
182
        *dst += bps;
183
    }
184
    if (le) *dst -= bps - 2;
185
}
186

    
187
static int pcm_encode_frame(AVCodecContext *avctx,
188
                            unsigned char *frame, int buf_size, void *data)
189
{
190
    int n, sample_size, v;
191
    short *samples;
192
    unsigned char *dst;
193

    
194
    switch(avctx->codec->id) {
195
    case CODEC_ID_PCM_S32LE:
196
    case CODEC_ID_PCM_S32BE:
197
    case CODEC_ID_PCM_U32LE:
198
    case CODEC_ID_PCM_U32BE:
199
        sample_size = 4;
200
        break;
201
    case CODEC_ID_PCM_S24LE:
202
    case CODEC_ID_PCM_S24BE:
203
    case CODEC_ID_PCM_U24LE:
204
    case CODEC_ID_PCM_U24BE:
205
    case CODEC_ID_PCM_S24DAUD:
206
        sample_size = 3;
207
        break;
208
    case CODEC_ID_PCM_S16LE:
209
    case CODEC_ID_PCM_S16BE:
210
    case CODEC_ID_PCM_U16LE:
211
    case CODEC_ID_PCM_U16BE:
212
        sample_size = 2;
213
        break;
214
    default:
215
        sample_size = 1;
216
        break;
217
    }
218
    n = buf_size / sample_size;
219
    samples = data;
220
    dst = frame;
221

    
222
    switch(avctx->codec->id) {
223
    case CODEC_ID_PCM_S32LE:
224
        encode_from16(4, 1, 0, &samples, &dst, n);
225
        break;
226
    case CODEC_ID_PCM_S32BE:
227
        encode_from16(4, 0, 0, &samples, &dst, n);
228
        break;
229
    case CODEC_ID_PCM_U32LE:
230
        encode_from16(4, 1, 1, &samples, &dst, n);
231
        break;
232
    case CODEC_ID_PCM_U32BE:
233
        encode_from16(4, 0, 1, &samples, &dst, n);
234
        break;
235
    case CODEC_ID_PCM_S24LE:
236
        encode_from16(3, 1, 0, &samples, &dst, n);
237
        break;
238
    case CODEC_ID_PCM_S24BE:
239
        encode_from16(3, 0, 0, &samples, &dst, n);
240
        break;
241
    case CODEC_ID_PCM_U24LE:
242
        encode_from16(3, 1, 1, &samples, &dst, n);
243
        break;
244
    case CODEC_ID_PCM_U24BE:
245
        encode_from16(3, 0, 1, &samples, &dst, n);
246
        break;
247
    case CODEC_ID_PCM_S24DAUD:
248
        for(;n>0;n--) {
249
            uint32_t tmp = ff_reverse[*samples >> 8] +
250
                           (ff_reverse[*samples & 0xff] << 8);
251
            tmp <<= 4; // sync flags would go here
252
            bytestream_put_be24(&dst, tmp);
253
            samples++;
254
        }
255
        break;
256
    case CODEC_ID_PCM_S16LE:
257
        for(;n>0;n--) {
258
            v = *samples++;
259
            bytestream_put_le16(&dst, v);
260
        }
261
        break;
262
    case CODEC_ID_PCM_S16BE:
263
        for(;n>0;n--) {
264
            v = *samples++;
265
            bytestream_put_be16(&dst, v);
266
        }
267
        break;
268
    case CODEC_ID_PCM_U16LE:
269
        for(;n>0;n--) {
270
            v = *samples++;
271
            v += 0x8000;
272
            bytestream_put_le16(&dst, v);
273
        }
274
        break;
275
    case CODEC_ID_PCM_U16BE:
276
        for(;n>0;n--) {
277
            v = *samples++;
278
            v += 0x8000;
279
            bytestream_put_be16(&dst, v);
280
        }
281
        break;
282
    case CODEC_ID_PCM_S8:
283
        for(;n>0;n--) {
284
            v = *samples++;
285
            dst[0] = v >> 8;
286
            dst++;
287
        }
288
        break;
289
    case CODEC_ID_PCM_U8:
290
        for(;n>0;n--) {
291
            v = *samples++;
292
            dst[0] = (v >> 8) + 128;
293
            dst++;
294
        }
295
        break;
296
    case CODEC_ID_PCM_ALAW:
297
        for(;n>0;n--) {
298
            v = *samples++;
299
            dst[0] = linear_to_alaw[(v + 32768) >> 2];
300
            dst++;
301
        }
302
        break;
303
    case CODEC_ID_PCM_MULAW:
304
        for(;n>0;n--) {
305
            v = *samples++;
306
            dst[0] = linear_to_ulaw[(v + 32768) >> 2];
307
            dst++;
308
        }
309
        break;
310
    default:
311
        return -1;
312
    }
313
    //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
314

    
315
    return dst - frame;
316
}
317

    
318
typedef struct PCMDecode {
319
    short table[256];
320
} PCMDecode;
321

    
322
static int pcm_decode_init(AVCodecContext * avctx)
323
{
324
    PCMDecode *s = avctx->priv_data;
325
    int i;
326

    
327
    switch(avctx->codec->id) {
328
    case CODEC_ID_PCM_ALAW:
329
        for(i=0;i<256;i++)
330
            s->table[i] = alaw2linear(i);
331
        break;
332
    case CODEC_ID_PCM_MULAW:
333
        for(i=0;i<256;i++)
334
            s->table[i] = ulaw2linear(i);
335
        break;
336
    default:
337
        break;
338
    }
339
    return 0;
340
}
341

    
342
/**
343
 * \brief convert samples to 16 bit
344
 * \param bps byte per sample for the source format, must be >= 2
345
 * \param le 0 for big-, 1 for little-endian
346
 * \param us 0 for signed, 1 for unsigned input
347
 * \param src input samples
348
 * \param samples output samples
349
 * \param src_len number of bytes in src
350
 */
351
static inline void decode_to16(int bps, int le, int us,
352
                               uint8_t **src, short **samples, int src_len)
353
{
354
    int usum = us ? -0x8000 : 0;
355
    register int n = src_len / bps;
356
    if (le) *src += bps - 2;
357
    for(;n>0;n--) {
358
        register int v;
359
        if (le) v = AV_RL16(*src);
360
        else    v = AV_RB16(*src);
361
        v += usum;
362
        *(*samples)++ = v;
363
        *src += bps;
364
    }
365
    if (le) *src -= bps - 2;
366
}
367

    
368
static int pcm_decode_frame(AVCodecContext *avctx,
369
                            void *data, int *data_size,
370
                            uint8_t *buf, int buf_size)
371
{
372
    PCMDecode *s = avctx->priv_data;
373
    int n;
374
    short *samples;
375
    uint8_t *src;
376

    
377
    samples = data;
378
    src = buf;
379

    
380
    n= av_get_bits_per_sample(avctx->codec_id)/8;
381
    if(n && buf_size % n){
382
        av_log(avctx, AV_LOG_ERROR, "invalid PCM packet\n");
383
        return -1;
384
    }
385

    
386
    buf_size= FFMIN(buf_size, *data_size/2);
387
    *data_size=0;
388

    
389
    switch(avctx->codec->id) {
390
    case CODEC_ID_PCM_S32LE:
391
        decode_to16(4, 1, 0, &src, &samples, buf_size);
392
        break;
393
    case CODEC_ID_PCM_S32BE:
394
        decode_to16(4, 0, 0, &src, &samples, buf_size);
395
        break;
396
    case CODEC_ID_PCM_U32LE:
397
        decode_to16(4, 1, 1, &src, &samples, buf_size);
398
        break;
399
    case CODEC_ID_PCM_U32BE:
400
        decode_to16(4, 0, 1, &src, &samples, buf_size);
401
        break;
402
    case CODEC_ID_PCM_S24LE:
403
        decode_to16(3, 1, 0, &src, &samples, buf_size);
404
        break;
405
    case CODEC_ID_PCM_S24BE:
406
        decode_to16(3, 0, 0, &src, &samples, buf_size);
407
        break;
408
    case CODEC_ID_PCM_U24LE:
409
        decode_to16(3, 1, 1, &src, &samples, buf_size);
410
        break;
411
    case CODEC_ID_PCM_U24BE:
412
        decode_to16(3, 0, 1, &src, &samples, buf_size);
413
        break;
414
    case CODEC_ID_PCM_S24DAUD:
415
        n = buf_size / 3;
416
        for(;n>0;n--) {
417
          uint32_t v = bytestream_get_be24(&src);
418
          v >>= 4; // sync flags are here
419
          *samples++ = ff_reverse[(v >> 8) & 0xff] +
420
                       (ff_reverse[v & 0xff] << 8);
421
        }
422
        break;
423
    case CODEC_ID_PCM_S16LE:
424
        n = buf_size >> 1;
425
        for(;n>0;n--) {
426
            *samples++ = bytestream_get_le16(&src);
427
        }
428
        break;
429
    case CODEC_ID_PCM_S16BE:
430
        n = buf_size >> 1;
431
        for(;n>0;n--) {
432
            *samples++ = bytestream_get_be16(&src);
433
        }
434
        break;
435
    case CODEC_ID_PCM_U16LE:
436
        n = buf_size >> 1;
437
        for(;n>0;n--) {
438
            *samples++ = bytestream_get_le16(&src) - 0x8000;
439
        }
440
        break;
441
    case CODEC_ID_PCM_U16BE:
442
        n = buf_size >> 1;
443
        for(;n>0;n--) {
444
            *samples++ = bytestream_get_be16(&src) - 0x8000;
445
        }
446
        break;
447
    case CODEC_ID_PCM_S8:
448
        n = buf_size;
449
        for(;n>0;n--) {
450
            *samples++ = src[0] << 8;
451
            src++;
452
        }
453
        break;
454
    case CODEC_ID_PCM_U8:
455
        n = buf_size;
456
        for(;n>0;n--) {
457
            *samples++ = ((int)src[0] - 128) << 8;
458
            src++;
459
        }
460
        break;
461
    case CODEC_ID_PCM_ALAW:
462
    case CODEC_ID_PCM_MULAW:
463
        n = buf_size;
464
        for(;n>0;n--) {
465
            *samples++ = s->table[src[0]];
466
            src++;
467
        }
468
        break;
469
    default:
470
        return -1;
471
    }
472
    *data_size = (uint8_t *)samples - (uint8_t *)data;
473
    return src - buf;
474
}
475

    
476
#define PCM_CODEC(id, name)                     \
477
AVCodec name ## _encoder = {                    \
478
    #name,                                      \
479
    CODEC_TYPE_AUDIO,                           \
480
    id,                                         \
481
    0,                                          \
482
    pcm_encode_init,                            \
483
    pcm_encode_frame,                           \
484
    pcm_encode_close,                           \
485
    NULL,                                       \
486
};                                              \
487
AVCodec name ## _decoder = {                    \
488
    #name,                                      \
489
    CODEC_TYPE_AUDIO,                           \
490
    id,                                         \
491
    sizeof(PCMDecode),                          \
492
    pcm_decode_init,                            \
493
    NULL,                                       \
494
    NULL,                                       \
495
    pcm_decode_frame,                           \
496
}
497

    
498
PCM_CODEC(CODEC_ID_PCM_S32LE, pcm_s32le);
499
PCM_CODEC(CODEC_ID_PCM_S32BE, pcm_s32be);
500
PCM_CODEC(CODEC_ID_PCM_U32LE, pcm_u32le);
501
PCM_CODEC(CODEC_ID_PCM_U32BE, pcm_u32be);
502
PCM_CODEC(CODEC_ID_PCM_S24LE, pcm_s24le);
503
PCM_CODEC(CODEC_ID_PCM_S24BE, pcm_s24be);
504
PCM_CODEC(CODEC_ID_PCM_U24LE, pcm_u24le);
505
PCM_CODEC(CODEC_ID_PCM_U24BE, pcm_u24be);
506
PCM_CODEC(CODEC_ID_PCM_S24DAUD, pcm_s24daud);
507
PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
508
PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
509
PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
510
PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
511
PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
512
PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
513
PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
514
PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
515

    
516
#undef PCM_CODEC