MythTV: pcm.c Source File

00001 /*
00002  * PCM codecs
00003  * Copyright (c) 2001 Fabrice Bellard.
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 #include "avcodec.h"
00028 #include "bitstream.h" // for ff_reverse
00029 #include "bytestream.h"
00030 
00031 /* from g711.c by SUN microsystems (unrestricted use) */
00032 
00033 #define         SIGN_BIT        (0x80)      /* Sign bit for a A-law byte. */
00034 #define         QUANT_MASK      (0xf)       /* Quantization field mask. */
00035 #define         NSEGS           (8)         /* Number of A-law segments. */
00036 #define         SEG_SHIFT       (4)         /* Left shift for segment number. */
00037 #define         SEG_MASK        (0x70)      /* Segment field mask. */
00038 
00039 #define         BIAS            (0x84)      /* Bias for linear code. */
00040 
00041 /*
00042  * alaw2linear() - Convert an A-law value to 16-bit linear PCM
00043  *
00044  */
00045 static int alaw2linear(unsigned char a_val)
00046 {
00047         int t;
00048         int seg;
00049 
00050         a_val ^= 0x55;
00051 
00052         t = a_val & QUANT_MASK;
00053         seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
00054         if(seg) t= (t + t + 1 + 32) << (seg + 2);
00055         else    t= (t + t + 1     ) << 3;
00056 
00057         return ((a_val & SIGN_BIT) ? t : -t);
00058 }
00059 
00060 static int ulaw2linear(unsigned char u_val)
00061 {
00062         int t;
00063 
00064         /* Complement to obtain normal u-law value. */
00065         u_val = ~u_val;
00066 
00067         /*
00068          * Extract and bias the quantization bits. Then
00069          * shift up by the segment number and subtract out the bias.
00070          */
00071         t = ((u_val & QUANT_MASK) << 3) + BIAS;
00072         t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
00073 
00074         return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
00075 }
00076 
00077 /* 16384 entries per table */
00078 static uint8_t linear_to_alaw[16384];
00079 static uint8_t linear_to_ulaw[16384];
00080 
00081 static void build_xlaw_table(uint8_t *linear_to_xlaw,
00082                              int (*xlaw2linear)(unsigned char),
00083                              int mask)
00084 {
00085     int i, j, v, v1, v2;
00086 
00087     j = 0;
00088     for(i=0;i<128;i++) {
00089         if (i != 127) {
00090             v1 = xlaw2linear(i ^ mask);
00091             v2 = xlaw2linear((i + 1) ^ mask);
00092             v = (v1 + v2 + 4) >> 3;
00093         } else {
00094             v = 8192;
00095         }
00096         for(;j<v;j++) {
00097             linear_to_xlaw[8192 + j] = (i ^ mask);
00098             if (j > 0)
00099                 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
00100         }
00101     }
00102     linear_to_xlaw[0] = linear_to_xlaw[1];
00103 }
00104 
00105 static int pcm_encode_init(AVCodecContext *avctx)
00106 {
00107     avctx->frame_size = 1;
00108     switch(avctx->codec->id) {
00109     case CODEC_ID_PCM_ALAW:
00110         build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
00111         break;
00112     case CODEC_ID_PCM_MULAW:
00113         build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
00114         break;
00115     default:
00116         break;
00117     }
00118 
00119     switch(avctx->codec->id) {
00120     case CODEC_ID_PCM_S32LE:
00121     case CODEC_ID_PCM_S32BE:
00122     case CODEC_ID_PCM_U32LE:
00123     case CODEC_ID_PCM_U32BE:
00124         avctx->block_align = 4 * avctx->channels;
00125         break;
00126     case CODEC_ID_PCM_S24LE:
00127     case CODEC_ID_PCM_S24BE:
00128     case CODEC_ID_PCM_U24LE:
00129     case CODEC_ID_PCM_U24BE:
00130     case CODEC_ID_PCM_S24DAUD:
00131         avctx->block_align = 3 * avctx->channels;
00132         break;
00133     case CODEC_ID_PCM_S16LE:
00134     case CODEC_ID_PCM_S16BE:
00135     case CODEC_ID_PCM_U16LE:
00136     case CODEC_ID_PCM_U16BE:
00137         avctx->block_align = 2 * avctx->channels;
00138         break;
00139     case CODEC_ID_PCM_S8:
00140     case CODEC_ID_PCM_U8:
00141     case CODEC_ID_PCM_MULAW:
00142     case CODEC_ID_PCM_ALAW:
00143         avctx->block_align = avctx->channels;
00144         break;
00145     default:
00146         break;
00147     }
00148 
00149     avctx->coded_frame= avcodec_alloc_frame();
00150     avctx->coded_frame->key_frame= 1;
00151 
00152     return 0;
00153 }
00154 
00155 static int pcm_encode_close(AVCodecContext *avctx)
00156 {
00157     av_freep(&avctx->coded_frame);
00158 
00159     return 0;
00160 }
00161 
00171 static inline void encode_from16(int bps, int le, int us,
00172                                short **samples, uint8_t **dst, int n) {
00173     int usum = us ? 0x8000 : 0;
00174     if (bps > 2)
00175         memset(*dst, 0, n * bps);
00176     if (le) *dst += bps - 2;
00177     for(;n>0;n--) {
00178         register int v = *(*samples)++;
00179         v += usum;
00180         if (le) AV_WL16(*dst, v);
00181         else    AV_WB16(*dst, v);
00182         *dst += bps;
00183     }
00184     if (le) *dst -= bps - 2;
00185 }
00186 
00187 static int pcm_encode_frame(AVCodecContext *avctx,
00188                             unsigned char *frame, int buf_size, void *data)
00189 {
00190     int n, sample_size, v;
00191     short *samples;
00192     unsigned char *dst;
00193 
00194     switch(avctx->codec->id) {
00195     case CODEC_ID_PCM_S32LE:
00196     case CODEC_ID_PCM_S32BE:
00197     case CODEC_ID_PCM_U32LE:
00198     case CODEC_ID_PCM_U32BE:
00199         sample_size = 4;
00200         break;
00201     case CODEC_ID_PCM_S24LE:
00202     case CODEC_ID_PCM_S24BE:
00203     case CODEC_ID_PCM_U24LE:
00204     case CODEC_ID_PCM_U24BE:
00205     case CODEC_ID_PCM_S24DAUD:
00206         sample_size = 3;
00207         break;
00208     case CODEC_ID_PCM_S16LE:
00209     case CODEC_ID_PCM_S16BE:
00210     case CODEC_ID_PCM_U16LE:
00211     case CODEC_ID_PCM_U16BE:
00212         sample_size = 2;
00213         break;
00214     default:
00215         sample_size = 1;
00216         break;
00217     }
00218     n = buf_size / sample_size;
00219     samples = data;
00220     dst = frame;
00221 
00222     switch(avctx->codec->id) {
00223     case CODEC_ID_PCM_S32LE:
00224         encode_from16(4, 1, 0, &samples, &dst, n);
00225         break;
00226     case CODEC_ID_PCM_S32BE:
00227         encode_from16(4, 0, 0, &samples, &dst, n);
00228         break;
00229     case CODEC_ID_PCM_U32LE:
00230         encode_from16(4, 1, 1, &samples, &dst, n);
00231         break;
00232     case CODEC_ID_PCM_U32BE:
00233         encode_from16(4, 0, 1, &samples, &dst, n);
00234         break;
00235     case CODEC_ID_PCM_S24LE:
00236         encode_from16(3, 1, 0, &samples, &dst, n);
00237         break;
00238     case CODEC_ID_PCM_S24BE:
00239         encode_from16(3, 0, 0, &samples, &dst, n);
00240         break;
00241     case CODEC_ID_PCM_U24LE:
00242         encode_from16(3, 1, 1, &samples, &dst, n);
00243         break;
00244     case CODEC_ID_PCM_U24BE:
00245         encode_from16(3, 0, 1, &samples, &dst, n);
00246         break;
00247     case CODEC_ID_PCM_S24DAUD:
00248         for(;n>0;n--) {
00249             uint32_t tmp = ff_reverse[*samples >> 8] +
00250                            (ff_reverse[*samples & 0xff] << 8);
00251             tmp <<= 4; // sync flags would go here
00252             bytestream_put_be24(&dst, tmp);
00253             samples++;
00254         }
00255         break;
00256     case CODEC_ID_PCM_S16LE:
00257         for(;n>0;n--) {
00258             v = *samples++;
00259             bytestream_put_le16(&dst, v);
00260         }
00261         break;
00262     case CODEC_ID_PCM_S16BE:
00263         for(;n>0;n--) {
00264             v = *samples++;
00265             bytestream_put_be16(&dst, v);
00266         }
00267         break;
00268     case CODEC_ID_PCM_U16LE:
00269         for(;n>0;n--) {
00270             v = *samples++;
00271             v += 0x8000;
00272             bytestream_put_le16(&dst, v);
00273         }
00274         break;
00275     case CODEC_ID_PCM_U16BE:
00276         for(;n>0;n--) {
00277             v = *samples++;
00278             v += 0x8000;
00279             bytestream_put_be16(&dst, v);
00280         }
00281         break;
00282     case CODEC_ID_PCM_S8:
00283         for(;n>0;n--) {
00284             v = *samples++;
00285             *dst++ = v >> 8;
00286         }
00287         break;
00288     case CODEC_ID_PCM_U8:
00289         for(;n>0;n--) {
00290             v = *samples++;
00291             *dst++ = (v >> 8) + 128;
00292         }
00293         break;
00294     case CODEC_ID_PCM_ZORK:
00295         for(;n>0;n--) {
00296             v= *samples++ >> 8;
00297             if(v<0)   v = -v;
00298             else      v+= 128;
00299             *dst++ = v;
00300         }
00301         break;
00302     case CODEC_ID_PCM_ALAW:
00303         for(;n>0;n--) {
00304             v = *samples++;
00305             *dst++ = linear_to_alaw[(v + 32768) >> 2];
00306         }
00307         break;
00308     case CODEC_ID_PCM_MULAW:
00309         for(;n>0;n--) {
00310             v = *samples++;
00311             *dst++ = linear_to_ulaw[(v + 32768) >> 2];
00312         }
00313         break;
00314     default:
00315         return -1;
00316     }
00317     //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
00318 
00319     return dst - frame;
00320 }
00321 
00322 typedef struct PCMDecode {
00323     short table[256];
00324 } PCMDecode;
00325 
00326 static int pcm_decode_init(AVCodecContext * avctx)
00327 {
00328     PCMDecode *s = avctx->priv_data;
00329     int i;
00330 
00331     switch(avctx->codec->id) {
00332     case CODEC_ID_PCM_ALAW:
00333         for(i=0;i<256;i++)
00334             s->table[i] = alaw2linear(i);
00335         break;
00336     case CODEC_ID_PCM_MULAW:
00337         for(i=0;i<256;i++)
00338             s->table[i] = ulaw2linear(i);
00339         break;
00340     default:
00341         break;
00342     }
00343     return 0;
00344 }
00345 
00355 static inline void decode_to16(int bps, int le, int us,
00356                                uint8_t **src, short **samples, int src_len)
00357 {
00358     int usum = us ? -0x8000 : 0;
00359     register int n = src_len / bps;
00360     if (le) *src += bps - 2;
00361     for(;n>0;n--) {
00362         register int v;
00363         if (le) v = AV_RL16(*src);
00364         else    v = AV_RB16(*src);
00365         v += usum;
00366         *(*samples)++ = v;
00367         *src += bps;
00368     }
00369     if (le) *src -= bps - 2;
00370 }
00371 
00372 static int pcm_decode_frame(AVCodecContext *avctx,
00373                             void *data, int *data_size,
00374                             uint8_t *buf, int buf_size)
00375 {
00376     PCMDecode *s = avctx->priv_data;
00377     int n;
00378     short *samples;
00379     uint8_t *src;
00380 
00381     samples = data;
00382     src = buf;
00383 
00384     n= av_get_bits_per_sample(avctx->codec_id)/8;
00385     if(n && buf_size % n){
00386         av_log(avctx, AV_LOG_ERROR, "invalid PCM packet\n");
00387         return -1;
00388     }
00389 
00390     buf_size= FFMIN(buf_size, *data_size/2);
00391     *data_size=0;
00392 
00393     switch(avctx->codec->id) {
00394     case CODEC_ID_PCM_S32LE:
00395         decode_to16(4, 1, 0, &src, &samples, buf_size);
00396         break;
00397     case CODEC_ID_PCM_S32BE:
00398         decode_to16(4, 0, 0, &src, &samples, buf_size);
00399         break;
00400     case CODEC_ID_PCM_U32LE:
00401         decode_to16(4, 1, 1, &src, &samples, buf_size);
00402         break;
00403     case CODEC_ID_PCM_U32BE:
00404         decode_to16(4, 0, 1, &src, &samples, buf_size);
00405         break;
00406     case CODEC_ID_PCM_S24LE:
00407         decode_to16(3, 1, 0, &src, &samples, buf_size);
00408         break;
00409     case CODEC_ID_PCM_S24BE:
00410         decode_to16(3, 0, 0, &src, &samples, buf_size);
00411         break;
00412     case CODEC_ID_PCM_U24LE:
00413         decode_to16(3, 1, 1, &src, &samples, buf_size);
00414         break;
00415     case CODEC_ID_PCM_U24BE:
00416         decode_to16(3, 0, 1, &src, &samples, buf_size);
00417         break;
00418     case CODEC_ID_PCM_S24DAUD:
00419         n = buf_size / 3;
00420         for(;n>0;n--) {
00421           uint32_t v = bytestream_get_be24(&src);
00422           v >>= 4; // sync flags are here
00423           *samples++ = ff_reverse[(v >> 8) & 0xff] +
00424                        (ff_reverse[v & 0xff] << 8);
00425         }
00426         break;
00427     case CODEC_ID_PCM_S16LE:
00428         n = buf_size >> 1;
00429         for(;n>0;n--) {
00430             *samples++ = bytestream_get_le16(&src);
00431         }
00432         break;
00433     case CODEC_ID_PCM_S16BE:
00434         n = buf_size >> 1;
00435         for(;n>0;n--) {
00436             *samples++ = bytestream_get_be16(&src);
00437         }
00438         break;
00439     case CODEC_ID_PCM_U16LE:
00440         n = buf_size >> 1;
00441         for(;n>0;n--) {
00442             *samples++ = bytestream_get_le16(&src) - 0x8000;
00443         }
00444         break;
00445     case CODEC_ID_PCM_U16BE:
00446         n = buf_size >> 1;
00447         for(;n>0;n--) {
00448             *samples++ = bytestream_get_be16(&src) - 0x8000;
00449         }
00450         break;
00451     case CODEC_ID_PCM_S8:
00452         n = buf_size;
00453         for(;n>0;n--) {
00454             *samples++ = *src++ << 8;
00455         }
00456         break;
00457     case CODEC_ID_PCM_U8:
00458         n = buf_size;
00459         for(;n>0;n--) {
00460             *samples++ = ((int)*src++ - 128) << 8;
00461         }
00462         break;
00463     case CODEC_ID_PCM_ZORK:
00464         n = buf_size;
00465         for(;n>0;n--) {
00466             int x= *src++;
00467             if(x&128) x-= 128;
00468             else      x = -x;
00469             *samples++ = x << 8;
00470         }
00471         break;
00472     case CODEC_ID_PCM_ALAW:
00473     case CODEC_ID_PCM_MULAW:
00474         n = buf_size;
00475         for(;n>0;n--) {
00476             *samples++ = s->table[*src++];
00477         }
00478         break;
00479     default:
00480         return -1;
00481     }
00482     *data_size = (uint8_t *)samples - (uint8_t *)data;
00483     return src - buf;
00484 }
00485 
00486 #ifdef CONFIG_ENCODERS
00487 #define PCM_ENCODER(id,name)                    \
00488 AVCodec name ## _encoder = {                    \
00489     #name,                                      \
00490     CODEC_TYPE_AUDIO,                           \
00491     id,                                         \
00492     0,                                          \
00493     pcm_encode_init,                            \
00494     pcm_encode_frame,                           \
00495     pcm_encode_close,                           \
00496     NULL,                                       \
00497 };
00498 #else
00499 #define PCM_ENCODER(id,name)
00500 #endif
00501 
00502 #ifdef CONFIG_DECODERS
00503 #define PCM_DECODER(id,name)                    \
00504 AVCodec name ## _decoder = {                    \
00505     #name,                                      \
00506     CODEC_TYPE_AUDIO,                           \
00507     id,                                         \
00508     sizeof(PCMDecode),                          \
00509     pcm_decode_init,                            \
00510     NULL,                                       \
00511     NULL,                                       \
00512     pcm_decode_frame,                           \
00513 };
00514 #else
00515 #define PCM_DECODER(id,name)
00516 #endif
00517 
00518 #define PCM_CODEC(id, name)                     \
00519 PCM_ENCODER(id,name) PCM_DECODER(id,name)
00520 
00521 PCM_CODEC(CODEC_ID_PCM_S32LE, pcm_s32le);
00522 PCM_CODEC(CODEC_ID_PCM_S32BE, pcm_s32be);
00523 PCM_CODEC(CODEC_ID_PCM_U32LE, pcm_u32le);
00524 PCM_CODEC(CODEC_ID_PCM_U32BE, pcm_u32be);
00525 PCM_CODEC(CODEC_ID_PCM_S24LE, pcm_s24le);
00526 PCM_CODEC(CODEC_ID_PCM_S24BE, pcm_s24be);
00527 PCM_CODEC(CODEC_ID_PCM_U24LE, pcm_u24le);
00528 PCM_CODEC(CODEC_ID_PCM_U24BE, pcm_u24be);
00529 PCM_CODEC(CODEC_ID_PCM_S24DAUD, pcm_s24daud);
00530 PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
00531 PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
00532 PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
00533 PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
00534 PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
00535 PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
00536 PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
00537 PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
00538 PCM_CODEC(CODEC_ID_PCM_ZORK, pcm_zork);