Cinelerra: hvirtual/quicktime/ffmpeg/libavcodec/pcm.c Source File

00001 /*
00002  * PCM codecs
00003  * Copyright (c) 2001 Fabrice Bellard.
00004  *
00005  * This library is free software; you can redistribute it and/or
00006  * modify it under the terms of the GNU Lesser General Public
00007  * License as published by the Free Software Foundation; either
00008  * version 2 of the License, or (at your option) any later version.
00009  *
00010  * This library is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013  * Lesser General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU Lesser General Public
00016  * License along with this library; if not, write to the Free Software
00017  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00018  */
00019  
00025 #include "avcodec.h"
00026 
00027 /* from g711.c by SUN microsystems (unrestricted use) */
00028 
00029 #define SIGN_BIT        (0x80)          /* Sign bit for a A-law byte. */
00030 #define QUANT_MASK      (0xf)           /* Quantization field mask. */
00031 #define NSEGS           (8)             /* Number of A-law segments. */
00032 #define SEG_SHIFT       (4)             /* Left shift for segment number. */
00033 #define SEG_MASK        (0x70)          /* Segment field mask. */
00034 
00035 #define BIAS            (0x84)          /* Bias for linear code. */
00036 
00037 /*
00038  * alaw2linear() - Convert an A-law value to 16-bit linear PCM
00039  *
00040  */
00041 static int alaw2linear(unsigned char    a_val)
00042 {
00043         int             t;
00044         int             seg;
00045 
00046         a_val ^= 0x55;
00047 
00048         t = a_val & QUANT_MASK;
00049         seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
00050         if(seg) t= (t + t + 1 + 32) << (seg + 2);
00051         else    t= (t + t + 1     ) << 3;
00052 
00053         return ((a_val & SIGN_BIT) ? t : -t);
00054 }
00055 
00056 static int ulaw2linear(unsigned char    u_val)
00057 {
00058         int             t;
00059 
00060         /* Complement to obtain normal u-law value. */
00061         u_val = ~u_val;
00062 
00063         /*
00064          * Extract and bias the quantization bits. Then
00065          * shift up by the segment number and subtract out the bias.
00066          */
00067         t = ((u_val & QUANT_MASK) << 3) + BIAS;
00068         t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
00069 
00070         return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
00071 }
00072 
00073 /* 16384 entries per table */
00074 static uint8_t *linear_to_alaw = NULL;
00075 static int linear_to_alaw_ref = 0;
00076 
00077 static uint8_t *linear_to_ulaw = NULL;
00078 static int linear_to_ulaw_ref = 0;
00079 
00080 static void build_xlaw_table(uint8_t *linear_to_xlaw, 
00081                              int (*xlaw2linear)(unsigned char),
00082                              int mask) 
00083 {
00084     int i, j, v, v1, v2;
00085 
00086     j = 0;
00087     for(i=0;i<128;i++) {
00088         if (i != 127) {
00089             v1 = xlaw2linear(i ^ mask);
00090             v2 = xlaw2linear((i + 1) ^ mask);
00091             v = (v1 + v2 + 4) >> 3;
00092         } else {
00093             v = 8192;
00094         }
00095         for(;j<v;j++) {
00096             linear_to_xlaw[8192 + j] = (i ^ mask);
00097             if (j > 0)
00098                 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
00099         }
00100     }
00101     linear_to_xlaw[0] = linear_to_xlaw[1];
00102 }
00103 
00104 static int pcm_encode_init(AVCodecContext *avctx)
00105 {
00106     avctx->frame_size = 1;
00107     switch(avctx->codec->id) {
00108     case CODEC_ID_PCM_ALAW:
00109         if (linear_to_alaw_ref == 0) {
00110             linear_to_alaw = av_malloc(16384);
00111             if (!linear_to_alaw)
00112                 return -1;
00113             build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
00114         }
00115         linear_to_alaw_ref++;
00116         break;
00117     case CODEC_ID_PCM_MULAW:
00118         if (linear_to_ulaw_ref == 0) {
00119             linear_to_ulaw = av_malloc(16384);
00120             if (!linear_to_ulaw)
00121                 return -1;
00122             build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
00123         }
00124         linear_to_ulaw_ref++;
00125         break;
00126     default:
00127         break;
00128     }
00129     
00130     switch(avctx->codec->id) {
00131     case CODEC_ID_PCM_S16LE:
00132     case CODEC_ID_PCM_S16BE:
00133     case CODEC_ID_PCM_U16LE:
00134     case CODEC_ID_PCM_U16BE:
00135         avctx->block_align = 2 * avctx->channels;
00136         break;
00137     case CODEC_ID_PCM_S8:
00138     case CODEC_ID_PCM_U8:
00139     case CODEC_ID_PCM_MULAW:
00140     case CODEC_ID_PCM_ALAW:
00141         avctx->block_align = avctx->channels;
00142         break;
00143     default:
00144         break;
00145     }
00146 
00147     avctx->coded_frame= avcodec_alloc_frame();
00148     avctx->coded_frame->key_frame= 1;
00149     
00150     return 0;
00151 }
00152 
00153 static int pcm_encode_close(AVCodecContext *avctx)
00154 {
00155     av_freep(&avctx->coded_frame);
00156 
00157     switch(avctx->codec->id) {
00158     case CODEC_ID_PCM_ALAW:
00159         if (--linear_to_alaw_ref == 0)
00160             av_free(linear_to_alaw);
00161         break;
00162     case CODEC_ID_PCM_MULAW:
00163         if (--linear_to_ulaw_ref == 0)
00164             av_free(linear_to_ulaw);
00165         break;
00166     default:
00167         /* nothing to free */
00168         break;
00169     }
00170     return 0;
00171 }
00172 
00173 static int pcm_encode_frame(AVCodecContext *avctx,
00174                             unsigned char *frame, int buf_size, void *data)
00175 {
00176     int n, sample_size, v;
00177     short *samples;
00178     unsigned char *dst;
00179 
00180     switch(avctx->codec->id) {
00181     case CODEC_ID_PCM_S16LE:
00182     case CODEC_ID_PCM_S16BE:
00183     case CODEC_ID_PCM_U16LE:
00184     case CODEC_ID_PCM_U16BE:
00185         sample_size = 2;
00186         break;
00187     default:
00188         sample_size = 1;
00189         break;
00190     }
00191     n = buf_size / sample_size;
00192     samples = data;
00193     dst = frame;
00194 
00195     switch(avctx->codec->id) {
00196     case CODEC_ID_PCM_S16LE:
00197         for(;n>0;n--) {
00198             v = *samples++;
00199             dst[0] = v & 0xff;
00200             dst[1] = v >> 8;
00201             dst += 2;
00202         }
00203         break;
00204     case CODEC_ID_PCM_S16BE:
00205         for(;n>0;n--) {
00206             v = *samples++;
00207             dst[0] = v >> 8;
00208             dst[1] = v;
00209             dst += 2;
00210         }
00211         break;
00212     case CODEC_ID_PCM_U16LE:
00213         for(;n>0;n--) {
00214             v = *samples++;
00215             v += 0x8000;
00216             dst[0] = v & 0xff;
00217             dst[1] = v >> 8;
00218             dst += 2;
00219         }
00220         break;
00221     case CODEC_ID_PCM_U16BE:
00222         for(;n>0;n--) {
00223             v = *samples++;
00224             v += 0x8000;
00225             dst[0] = v >> 8;
00226             dst[1] = v;
00227             dst += 2;
00228         }
00229         break;
00230     case CODEC_ID_PCM_S8:
00231         for(;n>0;n--) {
00232             v = *samples++;
00233             dst[0] = v >> 8;
00234             dst++;
00235         }
00236         break;
00237     case CODEC_ID_PCM_U8:
00238         for(;n>0;n--) {
00239             v = *samples++;
00240             dst[0] = (v >> 8) + 128;
00241             dst++;
00242         }
00243         break;
00244     case CODEC_ID_PCM_ALAW:
00245         for(;n>0;n--) {
00246             v = *samples++;
00247             dst[0] = linear_to_alaw[(v + 32768) >> 2];
00248             dst++;
00249         }
00250         break;
00251     case CODEC_ID_PCM_MULAW:
00252         for(;n>0;n--) {
00253             v = *samples++;
00254             dst[0] = linear_to_ulaw[(v + 32768) >> 2];
00255             dst++;
00256         }
00257         break;
00258     default:
00259         return -1;
00260     }
00261     //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
00262 
00263     return dst - frame;
00264 }
00265 
00266 typedef struct PCMDecode {
00267     short table[256];
00268 } PCMDecode;
00269 
00270 static int pcm_decode_init(AVCodecContext * avctx)
00271 {
00272     PCMDecode *s = avctx->priv_data;
00273     int i;
00274 
00275     switch(avctx->codec->id) {
00276     case CODEC_ID_PCM_ALAW:
00277         for(i=0;i<256;i++)
00278             s->table[i] = alaw2linear(i);
00279         break;
00280     case CODEC_ID_PCM_MULAW:
00281         for(i=0;i<256;i++)
00282             s->table[i] = ulaw2linear(i);
00283         break;
00284     default:
00285         break;
00286     }
00287     return 0;
00288 }
00289 
00290 static int pcm_decode_frame(AVCodecContext *avctx,
00291                             void *data, int *data_size,
00292                             uint8_t *buf, int buf_size)
00293 {
00294     PCMDecode *s = avctx->priv_data;
00295     int n;
00296     short *samples;
00297     uint8_t *src;
00298 
00299     samples = data;
00300     src = buf;
00301 
00302     if(buf_size > AVCODEC_MAX_AUDIO_FRAME_SIZE/2)
00303         buf_size = AVCODEC_MAX_AUDIO_FRAME_SIZE/2;
00304 
00305     switch(avctx->codec->id) {
00306     case CODEC_ID_PCM_S16LE:
00307         n = buf_size >> 1;
00308         for(;n>0;n--) {
00309             *samples++ = src[0] | (src[1] << 8);
00310             src += 2;
00311         }
00312         break;
00313     case CODEC_ID_PCM_S16BE:
00314         n = buf_size >> 1;
00315         for(;n>0;n--) {
00316             *samples++ = (src[0] << 8) | src[1];
00317             src += 2;
00318         }
00319         break;
00320     case CODEC_ID_PCM_U16LE:
00321         n = buf_size >> 1;
00322         for(;n>0;n--) {
00323             *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
00324             src += 2;
00325         }
00326         break;
00327     case CODEC_ID_PCM_U16BE:
00328         n = buf_size >> 1;
00329         for(;n>0;n--) {
00330             *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
00331             src += 2;
00332         }
00333         break;
00334     case CODEC_ID_PCM_S8:
00335         n = buf_size;
00336         for(;n>0;n--) {
00337             *samples++ = src[0] << 8;
00338             src++;
00339         }
00340         break;
00341     case CODEC_ID_PCM_U8:
00342         n = buf_size;
00343         for(;n>0;n--) {
00344             *samples++ = ((int)src[0] - 128) << 8;
00345             src++;
00346         }
00347         break;
00348     case CODEC_ID_PCM_ALAW:
00349     case CODEC_ID_PCM_MULAW:
00350         n = buf_size;
00351         for(;n>0;n--) {
00352             *samples++ = s->table[src[0]];
00353             src++;
00354         }
00355         break;
00356     default:
00357         return -1;
00358     }
00359     *data_size = (uint8_t *)samples - (uint8_t *)data;
00360     return src - buf;
00361 }
00362 
00363 #define PCM_CODEC(id, name)                     \
00364 AVCodec name ## _encoder = {                    \
00365     #name,                                      \
00366     CODEC_TYPE_AUDIO,                           \
00367     id,                                         \
00368     0,                                          \
00369     pcm_encode_init,                            \
00370     pcm_encode_frame,                           \
00371     pcm_encode_close,                           \
00372     NULL,                                       \
00373 };                                              \
00374 AVCodec name ## _decoder = {                    \
00375     #name,                                      \
00376     CODEC_TYPE_AUDIO,                           \
00377     id,                                         \
00378     sizeof(PCMDecode),                          \
00379     pcm_decode_init,                            \
00380     NULL,                                       \
00381     NULL,                                       \
00382     pcm_decode_frame,                           \
00383 }
00384 
00385 PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
00386 PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
00387 PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
00388 PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
00389 PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
00390 PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
00391 PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
00392 PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
00393 
00394 #undef PCM_CODEC