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1
/*
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 * PCM codecs
3
 * Copyright (c) 2001 Fabrice Bellard.
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21

    
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/**
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 * @file pcm.c
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 * PCM codecs
25
 */
26

    
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#include "avcodec.h"
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#include "bitstream.h" // for ff_reverse
29

    
30
/* from g711.c by SUN microsystems (unrestricted use) */
31

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

    
38
#define         BIAS            (0x84)      /* Bias for linear code. */
39

    
40
/*
41
 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
42
 *
43
 */
44
static int alaw2linear(unsigned char a_val)
45
{
46
        int t;
47
        int seg;
48

    
49
        a_val ^= 0x55;
50

    
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        t = a_val & QUANT_MASK;
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        seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
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        if(seg) t= (t + t + 1 + 32) << (seg + 2);
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        else    t= (t + t + 1     ) << 3;
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        return ((a_val & SIGN_BIT) ? t : -t);
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}
58

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

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

    
66
        /*
67
         * Extract and bias the quantization bits. Then
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         * shift up by the segment number and subtract out the bias.
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         */
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        t = ((u_val & QUANT_MASK) << 3) + BIAS;
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        t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
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        return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
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}
75

    
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/* 16384 entries per table */
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static uint8_t linear_to_alaw[16384];
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static uint8_t linear_to_ulaw[16384];
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static void build_xlaw_table(uint8_t *linear_to_xlaw,
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                             int (*xlaw2linear)(unsigned char),
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                             int mask)
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{
84
    int i, j, v, v1, v2;
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    j = 0;
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    for(i=0;i<128;i++) {
88
        if (i != 127) {
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            v1 = xlaw2linear(i ^ mask);
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            v2 = xlaw2linear((i + 1) ^ mask);
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            v = (v1 + v2 + 4) >> 3;
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        } else {
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            v = 8192;
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        }
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        for(;j<v;j++) {
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            linear_to_xlaw[8192 + j] = (i ^ mask);
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            if (j > 0)
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                linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
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        }
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    }
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    linear_to_xlaw[0] = linear_to_xlaw[1];
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}
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static int pcm_encode_init(AVCodecContext *avctx)
105
{
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    avctx->frame_size = 1;
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    switch(avctx->codec->id) {
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    case CODEC_ID_PCM_ALAW:
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        build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
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        break;
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    case CODEC_ID_PCM_MULAW:
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        build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
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        break;
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    default:
115
        break;
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    }
117

    
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    switch(avctx->codec->id) {
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    case CODEC_ID_PCM_S32LE:
120
    case CODEC_ID_PCM_S32BE:
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    case CODEC_ID_PCM_U32LE:
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    case CODEC_ID_PCM_U32BE:
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        avctx->block_align = 4 * avctx->channels;
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        break;
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    case CODEC_ID_PCM_S24LE:
126
    case CODEC_ID_PCM_S24BE:
127
    case CODEC_ID_PCM_U24LE:
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    case CODEC_ID_PCM_U24BE:
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    case CODEC_ID_PCM_S24DAUD:
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        avctx->block_align = 3 * avctx->channels;
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        break;
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    case CODEC_ID_PCM_S16LE:
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    case CODEC_ID_PCM_S16BE:
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    case CODEC_ID_PCM_U16LE:
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    case CODEC_ID_PCM_U16BE:
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        avctx->block_align = 2 * avctx->channels;
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        break;
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    case CODEC_ID_PCM_S8:
139
    case CODEC_ID_PCM_U8:
140
    case CODEC_ID_PCM_MULAW:
141
    case CODEC_ID_PCM_ALAW:
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        avctx->block_align = avctx->channels;
143
        break;
144
    default:
145
        break;
146
    }
147

    
148
    avctx->coded_frame= avcodec_alloc_frame();
149
    avctx->coded_frame->key_frame= 1;
150

    
151
    return 0;
152
}
153

    
154
static int pcm_encode_close(AVCodecContext *avctx)
155
{
156
    av_freep(&avctx->coded_frame);
157

    
158
    return 0;
159
}
160

    
161
/**
162
 * \brief convert samples from 16 bit
163
 * \param bps byte per sample for the destination format, must be >= 2
164
 * \param le 0 for big-, 1 for little-endian
165
 * \param us 0 for signed, 1 for unsigned output
166
 * \param samples input samples
167
 * \param dst output samples
168
 * \param n number of samples in samples buffer.
169
 */
170
static inline void encode_from16(int bps, int le, int us,
171
                               short **samples, uint8_t **dst, int n) {
172
    int usum = us ? 0x8000 : 0;
173
    if (bps > 2)
174
        memset(*dst, 0, n * bps);
175
    if (le) *dst += bps - 2;
176
    for(;n>0;n--) {
177
        register int v = *(*samples)++;
178
        v += usum;
179
        (*dst)[le] = v >> 8;
180
        (*dst)[1 - le] = v;
181
        *dst += bps;
182
    }
183
    if (le) *dst -= bps - 2;
184
}
185

    
186
static int pcm_encode_frame(AVCodecContext *avctx,
187
                            unsigned char *frame, int buf_size, void *data)
188
{
189
    int n, sample_size, v;
190
    short *samples;
191
    unsigned char *dst;
192

    
193
    switch(avctx->codec->id) {
194
    case CODEC_ID_PCM_S32LE:
195
    case CODEC_ID_PCM_S32BE:
196
    case CODEC_ID_PCM_U32LE:
197
    case CODEC_ID_PCM_U32BE:
198
        sample_size = 4;
199
        break;
200
    case CODEC_ID_PCM_S24LE:
201
    case CODEC_ID_PCM_S24BE:
202
    case CODEC_ID_PCM_U24LE:
203
    case CODEC_ID_PCM_U24BE:
204
    case CODEC_ID_PCM_S24DAUD:
205
        sample_size = 3;
206
        break;
207
    case CODEC_ID_PCM_S16LE:
208
    case CODEC_ID_PCM_S16BE:
209
    case CODEC_ID_PCM_U16LE:
210
    case CODEC_ID_PCM_U16BE:
211
        sample_size = 2;
212
        break;
213
    default:
214
        sample_size = 1;
215
        break;
216
    }
217
    n = buf_size / sample_size;
218
    samples = data;
219
    dst = frame;
220

    
221
    switch(avctx->codec->id) {
222
    case CODEC_ID_PCM_S32LE:
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        encode_from16(4, 1, 0, &samples, &dst, n);
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        break;
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    case CODEC_ID_PCM_S32BE:
226
        encode_from16(4, 0, 0, &samples, &dst, n);
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        break;
228
    case CODEC_ID_PCM_U32LE:
229
        encode_from16(4, 1, 1, &samples, &dst, n);
230
        break;
231
    case CODEC_ID_PCM_U32BE:
232
        encode_from16(4, 0, 1, &samples, &dst, n);
233
        break;
234
    case CODEC_ID_PCM_S24LE:
235
        encode_from16(3, 1, 0, &samples, &dst, n);
236
        break;
237
    case CODEC_ID_PCM_S24BE:
238
        encode_from16(3, 0, 0, &samples, &dst, n);
239
        break;
240
    case CODEC_ID_PCM_U24LE:
241
        encode_from16(3, 1, 1, &samples, &dst, n);
242
        break;
243
    case CODEC_ID_PCM_U24BE:
244
        encode_from16(3, 0, 1, &samples, &dst, n);
245
        break;
246
    case CODEC_ID_PCM_S24DAUD:
247
        for(;n>0;n--) {
248
            uint32_t tmp = ff_reverse[*samples >> 8] +
249
                           (ff_reverse[*samples & 0xff] << 8);
250
            tmp <<= 4; // sync flags would go here
251
            dst[2] = tmp & 0xff;
252
            tmp >>= 8;
253
            dst[1] = tmp & 0xff;
254
            dst[0] = tmp >> 8;
255
            samples++;
256
            dst += 3;
257
        }
258
        break;
259
    case CODEC_ID_PCM_S16LE:
260
        for(;n>0;n--) {
261
            v = *samples++;
262
            dst[0] = v & 0xff;
263
            dst[1] = v >> 8;
264
            dst += 2;
265
        }
266
        break;
267
    case CODEC_ID_PCM_S16BE:
268
        for(;n>0;n--) {
269
            v = *samples++;
270
            dst[0] = v >> 8;
271
            dst[1] = v;
272
            dst += 2;
273
        }
274
        break;
275
    case CODEC_ID_PCM_U16LE:
276
        for(;n>0;n--) {
277
            v = *samples++;
278
            v += 0x8000;
279
            dst[0] = v & 0xff;
280
            dst[1] = v >> 8;
281
            dst += 2;
282
        }
283
        break;
284
    case CODEC_ID_PCM_U16BE:
285
        for(;n>0;n--) {
286
            v = *samples++;
287
            v += 0x8000;
288
            dst[0] = v >> 8;
289
            dst[1] = v;
290
            dst += 2;
291
        }
292
        break;
293
    case CODEC_ID_PCM_S8:
294
        for(;n>0;n--) {
295
            v = *samples++;
296
            dst[0] = v >> 8;
297
            dst++;
298
        }
299
        break;
300
    case CODEC_ID_PCM_U8:
301
        for(;n>0;n--) {
302
            v = *samples++;
303
            dst[0] = (v >> 8) + 128;
304
            dst++;
305
        }
306
        break;
307
    case CODEC_ID_PCM_ALAW:
308
        for(;n>0;n--) {
309
            v = *samples++;
310
            dst[0] = linear_to_alaw[(v + 32768) >> 2];
311
            dst++;
312
        }
313
        break;
314
    case CODEC_ID_PCM_MULAW:
315
        for(;n>0;n--) {
316
            v = *samples++;
317
            dst[0] = linear_to_ulaw[(v + 32768) >> 2];
318
            dst++;
319
        }
320
        break;
321
    default:
322
        return -1;
323
    }
324
    //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
325

    
326
    return dst - frame;
327
}
328

    
329
typedef struct PCMDecode {
330
    short table[256];
331
} PCMDecode;
332

    
333
static int pcm_decode_init(AVCodecContext * avctx)
334
{
335
    PCMDecode *s = avctx->priv_data;
336
    int i;
337

    
338
    switch(avctx->codec->id) {
339
    case CODEC_ID_PCM_ALAW:
340
        for(i=0;i<256;i++)
341
            s->table[i] = alaw2linear(i);
342
        break;
343
    case CODEC_ID_PCM_MULAW:
344
        for(i=0;i<256;i++)
345
            s->table[i] = ulaw2linear(i);
346
        break;
347
    default:
348
        break;
349
    }
350
    return 0;
351
}
352

    
353
/**
354
 * \brief convert samples to 16 bit
355
 * \param bps byte per sample for the source format, must be >= 2
356
 * \param le 0 for big-, 1 for little-endian
357
 * \param us 0 for signed, 1 for unsigned input
358
 * \param src input samples
359
 * \param samples output samples
360
 * \param src_len number of bytes in src
361
 */
362
static inline void decode_to16(int bps, int le, int us,
363
                               uint8_t **src, short **samples, int src_len)
364
{
365
    int usum = us ? -0x8000 : 0;
366
    register int n = src_len / bps;
367
    if (le) *src += bps - 2;
368
    for(;n>0;n--) {
369
        *(*samples)++ = ((*src)[le] << 8 | (*src)[1 - le]) + usum;
370
        *src += bps;
371
    }
372
    if (le) *src -= bps - 2;
373
}
374

    
375
static int pcm_decode_frame(AVCodecContext *avctx,
376
                            void *data, int *data_size,
377
                            uint8_t *buf, int buf_size)
378
{
379
    PCMDecode *s = avctx->priv_data;
380
    int n;
381
    short *samples;
382
    uint8_t *src;
383

    
384
    samples = data;
385
    src = buf;
386

    
387
    n= av_get_bits_per_sample(avctx->codec_id)/8;
388
    if(n && buf_size % n){
389
        av_log(avctx, AV_LOG_ERROR, "invalid PCM packet\n");
390
        return -1;
391
    }
392

    
393
    buf_size= FFMIN(buf_size, *data_size/2);
394
    *data_size=0;
395

    
396
    switch(avctx->codec->id) {
397
    case CODEC_ID_PCM_S32LE:
398
        decode_to16(4, 1, 0, &src, &samples, buf_size);
399
        break;
400
    case CODEC_ID_PCM_S32BE:
401
        decode_to16(4, 0, 0, &src, &samples, buf_size);
402
        break;
403
    case CODEC_ID_PCM_U32LE:
404
        decode_to16(4, 1, 1, &src, &samples, buf_size);
405
        break;
406
    case CODEC_ID_PCM_U32BE:
407
        decode_to16(4, 0, 1, &src, &samples, buf_size);
408
        break;
409
    case CODEC_ID_PCM_S24LE:
410
        decode_to16(3, 1, 0, &src, &samples, buf_size);
411
        break;
412
    case CODEC_ID_PCM_S24BE:
413
        decode_to16(3, 0, 0, &src, &samples, buf_size);
414
        break;
415
    case CODEC_ID_PCM_U24LE:
416
        decode_to16(3, 1, 1, &src, &samples, buf_size);
417
        break;
418
    case CODEC_ID_PCM_U24BE:
419
        decode_to16(3, 0, 1, &src, &samples, buf_size);
420
        break;
421
    case CODEC_ID_PCM_S24DAUD:
422
        n = buf_size / 3;
423
        for(;n>0;n--) {
424
          uint32_t v = src[0] << 16 | src[1] << 8 | src[2];
425
          v >>= 4; // sync flags are here
426
          *samples++ = ff_reverse[(v >> 8) & 0xff] +
427
                       (ff_reverse[v & 0xff] << 8);
428
          src += 3;
429
        }
430
        break;
431
    case CODEC_ID_PCM_S16LE:
432
        n = buf_size >> 1;
433
        for(;n>0;n--) {
434
            *samples++ = src[0] | (src[1] << 8);
435
            src += 2;
436
        }
437
        break;
438
    case CODEC_ID_PCM_S16BE:
439
        n = buf_size >> 1;
440
        for(;n>0;n--) {
441
            *samples++ = (src[0] << 8) | src[1];
442
            src += 2;
443
        }
444
        break;
445
    case CODEC_ID_PCM_U16LE:
446
        n = buf_size >> 1;
447
        for(;n>0;n--) {
448
            *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
449
            src += 2;
450
        }
451
        break;
452
    case CODEC_ID_PCM_U16BE:
453
        n = buf_size >> 1;
454
        for(;n>0;n--) {
455
            *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
456
            src += 2;
457
        }
458
        break;
459
    case CODEC_ID_PCM_S8:
460
        n = buf_size;
461
        for(;n>0;n--) {
462
            *samples++ = src[0] << 8;
463
            src++;
464
        }
465
        break;
466
    case CODEC_ID_PCM_U8:
467
        n = buf_size;
468
        for(;n>0;n--) {
469
            *samples++ = ((int)src[0] - 128) << 8;
470
            src++;
471
        }
472
        break;
473
    case CODEC_ID_PCM_ALAW:
474
    case CODEC_ID_PCM_MULAW:
475
        n = buf_size;
476
        for(;n>0;n--) {
477
            *samples++ = s->table[src[0]];
478
            src++;
479
        }
480
        break;
481
    default:
482
        return -1;
483
    }
484
    *data_size = (uint8_t *)samples - (uint8_t *)data;
485
    return src - buf;
486
}
487

    
488
#define PCM_CODEC(id, name)                     \
489
AVCodec name ## _encoder = {                    \
490
    #name,                                      \
491
    CODEC_TYPE_AUDIO,                           \
492
    id,                                         \
493
    0,                                          \
494
    pcm_encode_init,                            \
495
    pcm_encode_frame,                           \
496
    pcm_encode_close,                           \
497
    NULL,                                       \
498
};                                              \
499
AVCodec name ## _decoder = {                    \
500
    #name,                                      \
501
    CODEC_TYPE_AUDIO,                           \
502
    id,                                         \
503
    sizeof(PCMDecode),                          \
504
    pcm_decode_init,                            \
505
    NULL,                                       \
506
    NULL,                                       \
507
    pcm_decode_frame,                           \
508
}
509

    
510
PCM_CODEC(CODEC_ID_PCM_S32LE, pcm_s32le);
511
PCM_CODEC(CODEC_ID_PCM_S32BE, pcm_s32be);
512
PCM_CODEC(CODEC_ID_PCM_U32LE, pcm_u32le);
513
PCM_CODEC(CODEC_ID_PCM_U32BE, pcm_u32be);
514
PCM_CODEC(CODEC_ID_PCM_S24LE, pcm_s24le);
515
PCM_CODEC(CODEC_ID_PCM_S24BE, pcm_s24be);
516
PCM_CODEC(CODEC_ID_PCM_U24LE, pcm_u24le);
517
PCM_CODEC(CODEC_ID_PCM_U24BE, pcm_u24be);
518
PCM_CODEC(CODEC_ID_PCM_S24DAUD, pcm_s24daud);
519
PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
520
PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
521
PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
522
PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
523
PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
524
PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
525
PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
526
PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
527

    
528
#undef PCM_CODEC