quicktime/ffmpeg/libavcodec/pcm.c

   1 /*
   2  * PCM codecs
   3  * Copyright (c) 2001 Fabrice Bellard.
   4  *
   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.
   9  *
  10  * This library 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 GNU
  13  * Lesser General Public License for more details.
  14  *
  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
  18  */
  19
  20 /**
  21  * @file pcm.c
  22  * PCM codecs
  23  */
  24
  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  */
  41 static int alaw2linear(unsigned char    a_val)
  42 {
  43         int             t;
  44         int             seg;
  45
  46         a_val ^= 0x55;
  47
  48         t = a_val & QUANT_MASK;
  49         seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
  50         if(seg) t= (t + t + 1 + 32) << (seg + 2);
  51         else    t= (t + t + 1     ) << 3;
  52
  53         return ((a_val & SIGN_BIT) ? t : -t);
  54 }
  55
  56 static 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 */
  74 static uint8_t *linear_to_alaw = NULL;
  75 static int linear_to_alaw_ref = 0;
  76
  77 static uint8_t *linear_to_ulaw = NULL;
  78 static int linear_to_ulaw_ref = 0;
  79
  80 static void build_xlaw_table(uint8_t *linear_to_xlaw,
  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
 104 static int pcm_encode_init(AVCodecContext *avctx)
 105 {
 106     avctx->frame_size = 1;
 107     switch(avctx->codec->id) {
 108     case CODEC_ID_PCM_ALAW:
 109         if (linear_to_alaw_ref == 0) {
 110             linear_to_alaw = av_malloc(16384);
 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) {
 119             linear_to_ulaw = av_malloc(16384);
 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     }
 129
 130     switch(avctx->codec->id) {
 131     case CODEC_ID_PCM_S16LE:
 132     case CODEC_ID_PCM_S16BE:
 133     case CODEC_ID_PCM_U16LE:
 134     case CODEC_ID_PCM_U16BE:
 135         avctx->block_align = 2 * avctx->channels;
 136         break;
 137     case CODEC_ID_PCM_S8:
 138     case CODEC_ID_PCM_U8:
 139     case CODEC_ID_PCM_MULAW:
 140     case CODEC_ID_PCM_ALAW:
 141         avctx->block_align = avctx->channels;
 142         break;
 143     default:
 144         break;
 145     }
 146
 147     avctx->coded_frame= avcodec_alloc_frame();
 148     avctx->coded_frame->key_frame= 1;
 149
 150     return 0;
 151 }
 152
 153 static int pcm_encode_close(AVCodecContext *avctx)
 154 {
 155     av_freep(&avctx->coded_frame);
 156
 157     switch(avctx->codec->id) {
 158     case CODEC_ID_PCM_ALAW:
 159         if (--linear_to_alaw_ref == 0)
 160             av_free(linear_to_alaw);
 161         break;
 162     case CODEC_ID_PCM_MULAW:
 163         if (--linear_to_ulaw_ref == 0)
 164             av_free(linear_to_ulaw);
 165         break;
 166     default:
 167         /* nothing to free */
 168         break;
 169     }
 170     return 0;
 171 }
 172
 173 static int pcm_encode_frame(AVCodecContext *avctx,
 174                             unsigned char *frame, int buf_size, void *data)
 175 {
 176     int n, sample_size, v;
 177     short *samples;
 178     unsigned char *dst;
 179
 180     switch(avctx->codec->id) {
 181     case CODEC_ID_PCM_S16LE:
 182     case CODEC_ID_PCM_S16BE:
 183     case CODEC_ID_PCM_U16LE:
 184     case CODEC_ID_PCM_U16BE:
 185         sample_size = 2;
 186         break;
 187     default:
 188         sample_size = 1;
 189         break;
 190     }
 191     n = buf_size / sample_size;
 192     samples = data;
 193     dst = frame;
 194
 195     switch(avctx->codec->id) {
 196     case CODEC_ID_PCM_S16LE:
 197         for(;n>0;n--) {
 198             v = *samples++;
 199             dst[0] = v & 0xff;
 200             dst[1] = v >> 8;
 201             dst += 2;
 202         }
 203         break;
 204     case CODEC_ID_PCM_S16BE:
 205         for(;n>0;n--) {
 206             v = *samples++;
 207             dst[0] = v >> 8;
 208             dst[1] = v;
 209             dst += 2;
 210         }
 211         break;
 212     case CODEC_ID_PCM_U16LE:
 213         for(;n>0;n--) {
 214             v = *samples++;
 215             v += 0x8000;
 216             dst[0] = v & 0xff;
 217             dst[1] = v >> 8;
 218             dst += 2;
 219         }
 220         break;
 221     case CODEC_ID_PCM_U16BE:
 222         for(;n>0;n--) {
 223             v = *samples++;
 224             v += 0x8000;
 225             dst[0] = v >> 8;
 226             dst[1] = v;
 227             dst += 2;
 228         }
 229         break;
 230     case CODEC_ID_PCM_S8:
 231         for(;n>0;n--) {
 232             v = *samples++;
 233             dst[0] = v >> 8;
 234             dst++;
 235         }
 236         break;
 237     case CODEC_ID_PCM_U8:
 238         for(;n>0;n--) {
 239             v = *samples++;
 240             dst[0] = (v >> 8) + 128;
 241             dst++;
 242         }
 243         break;
 244     case CODEC_ID_PCM_ALAW:
 245         for(;n>0;n--) {
 246             v = *samples++;
 247             dst[0] = linear_to_alaw[(v + 32768) >> 2];
 248             dst++;
 249         }
 250         break;
 251     case CODEC_ID_PCM_MULAW:
 252         for(;n>0;n--) {
 253             v = *samples++;
 254             dst[0] = linear_to_ulaw[(v + 32768) >> 2];
 255             dst++;
 256         }
 257         break;
 258     default:
 259         return -1;
 260     }
 261     //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
 262
 263     return dst - frame;
 264 }
 265
 266 typedef struct PCMDecode {
 267     short table[256];
 268 } PCMDecode;
 269
 270 static int pcm_decode_init(AVCodecContext * avctx)
 271 {
 272     PCMDecode *s = avctx->priv_data;
 273     int i;
 274
 275     switch(avctx->codec->id) {
 276     case CODEC_ID_PCM_ALAW:
 277         for(i=0;i<256;i++)
 278             s->table[i] = alaw2linear(i);
 279         break;
 280     case CODEC_ID_PCM_MULAW:
 281         for(i=0;i<256;i++)
 282             s->table[i] = ulaw2linear(i);
 283         break;
 284     default:
 285         break;
 286     }
 287     return 0;
 288 }
 289
 290 static int pcm_decode_frame(AVCodecContext *avctx,
 291                             void *data, int *data_size,
 292                             uint8_t *buf, int buf_size)
 293 {
 294     PCMDecode *s = avctx->priv_data;
 295     int n;
 296     short *samples;
 297     uint8_t *src;
 298
 299     samples = data;
 300     src = buf;
 301
 302     if(buf_size > AVCODEC_MAX_AUDIO_FRAME_SIZE/2)
 303         buf_size = AVCODEC_MAX_AUDIO_FRAME_SIZE/2;
 304
 305     switch(avctx->codec->id) {
 306     case CODEC_ID_PCM_S16LE:
 307         n = buf_size >> 1;
 308         for(;n>0;n--) {
 309             *samples++ = src[0] | (src[1] << 8);
 310             src += 2;
 311         }
 312         break;
 313     case CODEC_ID_PCM_S16BE:
 314         n = buf_size >> 1;
 315         for(;n>0;n--) {
 316             *samples++ = (src[0] << 8) | src[1];
 317             src += 2;
 318         }
 319         break;
 320     case CODEC_ID_PCM_U16LE:
 321         n = buf_size >> 1;
 322         for(;n>0;n--) {
 323             *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
 324             src += 2;
 325         }
 326         break;
 327     case CODEC_ID_PCM_U16BE:
 328         n = buf_size >> 1;
 329         for(;n>0;n--) {
 330             *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
 331             src += 2;
 332         }
 333         break;
 334     case CODEC_ID_PCM_S8:
 335         n = buf_size;
 336         for(;n>0;n--) {
 337             *samples++ = src[0] << 8;
 338             src++;
 339         }
 340         break;
 341     case CODEC_ID_PCM_U8:
 342         n = buf_size;
 343         for(;n>0;n--) {
 344             *samples++ = ((int)src[0] - 128) << 8;
 345             src++;
 346         }
 347         break;
 348     case CODEC_ID_PCM_ALAW:
 349     case CODEC_ID_PCM_MULAW:
 350         n = buf_size;
 351         for(;n>0;n--) {
 352             *samples++ = s->table[src[0]];
 353             src++;
 354         }
 355         break;
 356     default:
 357         return -1;
 358     }
 359     *data_size = (uint8_t *)samples - (uint8_t *)data;
 360     return src - buf;
 361 }
 362
 363 #define PCM_CODEC(id, name)                     \
 364 AVCodec name ## _encoder = {                    \
 365     #name,                                      \
 366     CODEC_TYPE_AUDIO,                           \
 367     id,                                         \
 368     0,                                          \
 369     pcm_encode_init,                            \
 370     pcm_encode_frame,                           \
 371     pcm_encode_close,                           \
 372     NULL,                                       \
 373 };                                              \
 374 AVCodec name ## _decoder = {                    \
 375     #name,                                      \
 376     CODEC_TYPE_AUDIO,                           \
 377     id,                                         \
 378     sizeof(PCMDecode),                          \
 379     pcm_decode_init,                            \
 380     NULL,                                       \
 381     NULL,                                       \
 382     pcm_decode_frame,                           \
 383 }
 384
 385 PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
 386 PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
 387 PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
 388 PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
 389 PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
 390 PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
 391 PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
 392 PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
 393
 394 #undef PCM_CODEC