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FFmpeg/libavcodec/adpcm.c

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  1. /*

  2.  * ADPCM codecs

  3.  * Copyright (c) 2001-2003 The ffmpeg Project

  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. #include "avcodec.h"

  20. 

  21. /**

  22.  * @file adpcm.c

  23.  * ADPCM codecs.

  24.  * First version by Francois Revol revol@free.fr

  25.  * Fringe ADPCM codecs (e.g., DK3, DK4, Westwood)

  26.  *   by Mike Melanson (melanson@pcisys.net)

  27.  *

  28.  * Features and limitations:

  29.  *

  30.  * Reference documents:

  31.  * http://www.pcisys.net/~melanson/codecs/simpleaudio.html

  32.  * http://www.geocities.com/SiliconValley/8682/aud3.txt

  33.  * http://openquicktime.sourceforge.net/plugins.htm

  34.  * XAnim sources (xa_codec.c) http://www.rasnaimaging.com/people/lapus/download.html

  35.  * http://www.cs.ucla.edu/~leec/mediabench/applications.html

  36.  * SoX source code http://home.sprynet.com/~cbagwell/sox.html

  37.  */

  38. 

  39. #define BLKSIZE 1024

  40. 

  41. #define CLAMP_TO_SHORT(value) \

  42. if (value > 32767) \

  43.     value = 32767; \

  44. else if (value < -32768) \

  45.     value = -32768; \

  46. 

  47. /* step_table[] and index_table[] are from the ADPCM reference source */

  48. /* This is the index table: */

  49. static const int index_table[16] = {

  50.     -1, -1, -1, -1, 2, 4, 6, 8,

  51.     -1, -1, -1, -1, 2, 4, 6, 8,

  52. };

  53. 

  54. /** 

  55.  * This is the step table. Note that many programs use slight deviations from

  56.  * this table, but such deviations are negligible:

  57.  */

  58. static const int step_table[89] = {

  59.     7, 8, 9, 10, 11, 12, 13, 14, 16, 17,

  60.     19, 21, 23, 25, 28, 31, 34, 37, 41, 45,

  61.     50, 55, 60, 66, 73, 80, 88, 97, 107, 118,

  62.     130, 143, 157, 173, 190, 209, 230, 253, 279, 307,

  63.     337, 371, 408, 449, 494, 544, 598, 658, 724, 796,

  64.     876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,

  65.     2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,

  66.     5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,

  67.     15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767

  68. };

  69. 

  70. /* Those are for MS-ADPCM */

  71. /* AdaptationTable[], AdaptCoeff1[], and AdaptCoeff2[] are from libsndfile */

  72. static const int AdaptationTable[] = {

  73.         230, 230, 230, 230, 307, 409, 512, 614,

  74.         768, 614, 512, 409, 307, 230, 230, 230

  75. };

  76. 

  77. static const int AdaptCoeff1[] = {

  78.         256, 512, 0, 192, 240, 460, 392

  79. };

  80. 

  81. static const int AdaptCoeff2[] = {

  82.         0, -256, 0, 64, 0, -208, -232

  83. };

  84. 

  85. /* end of tables */

  86. 

  87. typedef struct ADPCMChannelStatus {

  88.     int predictor;

  89.     short int step_index;

  90.     int step;

  91.     /* for encoding */

  92.     int prev_sample;

  93. 

  94.     /* MS version */

  95.     short sample1;

  96.     short sample2;

  97.     int coeff1;

  98.     int coeff2;

  99.     int idelta;

  100. } ADPCMChannelStatus;

  101. 

  102. typedef struct ADPCMContext {

  103.     int channel; /* for stereo MOVs, decode left, then decode right, then tell it's decoded */

  104.     ADPCMChannelStatus status[2];

  105.     short sample_buffer[32]; /* hold left samples while waiting for right samples */

  106. } ADPCMContext;

  107. 

  108. /* XXX: implement encoding */

  109. 

  110. static int adpcm_encode_init(AVCodecContext *avctx)

  111. {

  112.     if (avctx->channels > 2)

  113.         return -1; /* only stereo or mono =) */

  114.     switch(avctx->codec->id) {

  115.     case CODEC_ID_ADPCM_IMA_QT:

  116.         fprintf(stderr, "ADPCM: codec admcp_ima_qt unsupported for encoding !\n");

  117.         avctx->frame_size = 64; /* XXX: can multiple of avctx->channels * 64 (left and right blocks are interleaved) */

  118.         return -1;

  119.         break;

  120.     case CODEC_ID_ADPCM_IMA_WAV:

  121.         avctx->frame_size = (BLKSIZE - 4 * avctx->channels) * 8 / (4 * avctx->channels) + 1; /* each 16 bits sample gives one nibble */

  122.                                                              /* and we have 4 bytes per channel overhead */

  123.         avctx->block_align = BLKSIZE;

  124.         /* seems frame_size isn't taken into account... have to buffer the samples :-( */

  125.         break;

  126.     case CODEC_ID_ADPCM_MS:

  127.         fprintf(stderr, "ADPCM: codec admcp_ms unsupported for encoding !\n");

  128.         return -1;

  129.         break;

  130.     default:

  131.         return -1;

  132.         break;

  133.     }

  134. 

  135.     avctx->coded_frame= avcodec_alloc_frame();

  136.     avctx->coded_frame->key_frame= 1;

  137. 

  138.     return 0;

  139. }

  140. 

  141. static int adpcm_encode_close(AVCodecContext *avctx)

  142. {

  143.     av_freep(&avctx->coded_frame);

  144. 

  145.     return 0;

  146. }

  147. 

  148. 

  149. static inline unsigned char adpcm_ima_compress_sample(ADPCMChannelStatus *c, short sample)

  150. {

  151.     int step_index;

  152.     unsigned char nibble;

  153.     

  154.     int sign = 0; /* sign bit of the nibble (MSB) */

  155.     int delta, predicted_delta;

  156. 

  157.     delta = sample - c->prev_sample;

  158. 

  159.     if (delta < 0) {

  160.         sign = 1;

  161.         delta = -delta;

  162.     }

  163. 

  164.     step_index = c->step_index;

  165. 

  166.     /* nibble = 4 * delta / step_table[step_index]; */

  167.     nibble = (delta << 2) / step_table[step_index];

  168. 

  169.     if (nibble > 7)

  170.         nibble = 7;

  171. 

  172.     step_index += index_table[nibble];

  173.     if (step_index < 0)

  174.         step_index = 0;

  175.     if (step_index > 88)

  176.         step_index = 88;

  177. 

  178.     /* what the decoder will find */

  179.     predicted_delta = ((step_table[step_index] * nibble) / 4) + (step_table[step_index] / 8);

  180. 

  181.     if (sign)

  182.         c->prev_sample -= predicted_delta;

  183.     else

  184.         c->prev_sample += predicted_delta;

  185. 

  186.     CLAMP_TO_SHORT(c->prev_sample);

  187. 

  188. 

  189.     nibble += sign << 3; /* sign * 8 */   

  190. 

  191.     /* save back */

  192.     c->step_index = step_index;

  193. 

  194.     return nibble;

  195. }

  196. 

  197. static int adpcm_encode_frame(AVCodecContext *avctx,

  198. 			    unsigned char *frame, int buf_size, void *data)

  199. {

  200.     int n;

  201.     short *samples;

  202.     unsigned char *dst;

  203.     ADPCMContext *c = avctx->priv_data;

  204. 

  205.     dst = frame;

  206.     samples = (short *)data;

  207. /*    n = (BLKSIZE - 4 * avctx->channels) / (2 * 8 * avctx->channels); */

  208. 

  209.     switch(avctx->codec->id) {

  210.     case CODEC_ID_ADPCM_IMA_QT: /* XXX: can't test until we get .mov writer */

  211.         break;

  212.     case CODEC_ID_ADPCM_IMA_WAV:

  213.         n = avctx->frame_size / 8;

  214.             c->status[0].prev_sample = (signed short)samples[0]; /* XXX */

  215. /*            c->status[0].step_index = 0; *//* XXX: not sure how to init the state machine */

  216.             *dst++ = (c->status[0].prev_sample) & 0xFF; /* little endian */

  217.             *dst++ = (c->status[0].prev_sample >> 8) & 0xFF;

  218.             *dst++ = (unsigned char)c->status[0].step_index;

  219.             *dst++ = 0; /* unknown */

  220.             samples++;

  221.             if (avctx->channels == 2) {

  222.                 c->status[1].prev_sample = (signed short)samples[0];

  223. /*                c->status[1].step_index = 0; */

  224.                 *dst++ = (c->status[1].prev_sample) & 0xFF;

  225.                 *dst++ = (c->status[1].prev_sample >> 8) & 0xFF;

  226.                 *dst++ = (unsigned char)c->status[1].step_index;

  227.                 *dst++ = 0;

  228.                 samples++;

  229.             }

  230.         

  231.             /* stereo: 4 bytes (8 samples) for left, 4 bytes for right, 4 bytes left, ... */

  232.             for (; n>0; n--) {

  233.                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[0]) & 0x0F;

  234.                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels]) << 4) & 0xF0;

  235.                 dst++;

  236.                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 2]) & 0x0F;

  237.                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 3]) << 4) & 0xF0;

  238.                 dst++;

  239.                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 4]) & 0x0F;

  240.                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 5]) << 4) & 0xF0;

  241.                 dst++;

  242.                 *dst = adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 6]) & 0x0F;

  243.                 *dst |= (adpcm_ima_compress_sample(&c->status[0], samples[avctx->channels * 7]) << 4) & 0xF0;

  244.                 dst++;

  245.                 /* right channel */

  246.                 if (avctx->channels == 2) {

  247.                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[1]);

  248.                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[3]) << 4;

  249.                     dst++;

  250.                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[5]);

  251.                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[7]) << 4;

  252.                     dst++;

  253.                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[9]);

  254.                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[11]) << 4;

  255.                     dst++;

  256.                     *dst = adpcm_ima_compress_sample(&c->status[1], samples[13]);

  257.                     *dst |= adpcm_ima_compress_sample(&c->status[1], samples[15]) << 4;

  258.                     dst++;

  259.                 }

  260.                 samples += 8 * avctx->channels;

  261.             }

  262.         break;

  263.     default:

  264.         return -1;

  265.     }

  266.     return dst - frame;

  267. }

  268. 

  269. static int adpcm_decode_init(AVCodecContext * avctx)

  270. {

  271.     ADPCMContext *c = avctx->priv_data;

  272. 

  273.     c->channel = 0;

  274.     c->status[0].predictor = c->status[1].predictor = 0;

  275.     c->status[0].step_index = c->status[1].step_index = 0;

  276.     c->status[0].step = c->status[1].step = 0;

  277. 

  278.     switch(avctx->codec->id) {

  279.     default:

  280.         break;

  281.     }

  282.     return 0;

  283. }

  284. 

  285. static inline short adpcm_ima_expand_nibble(ADPCMChannelStatus *c, char nibble)

  286. {

  287.     int step_index;

  288.     int predictor;

  289.     int sign, delta, diff, step;

  290. 

  291.     step = step_table[c->step_index];

  292.     step_index = c->step_index + index_table[(unsigned)nibble];

  293.     if (step_index < 0) step_index = 0;

  294.     else if (step_index > 88) step_index = 88;

  295. 

  296.     sign = nibble & 8;

  297.     delta = nibble & 7;

  298.     /* perform direct multiplication instead of series of jumps proposed by

  299.      * the reference ADPCM implementation since modern CPUs can do the mults

  300.      * quickly enough */

  301.     diff = ((2 * delta + 1) * step) >> 3;

  302.     predictor = c->predictor;

  303.     if (sign) predictor -= diff;

  304.     else predictor += diff;

  305. 

  306.     CLAMP_TO_SHORT(predictor);

  307.     c->predictor = predictor;

  308.     c->step_index = step_index;

  309. 

  310.     return (short)predictor;

  311. }

  312. 

  313. static inline short adpcm_4xa_expand_nibble(ADPCMChannelStatus *c, char nibble)

  314. {

  315.     int step_index;

  316.     int predictor;

  317.     int sign, delta, diff, step;

  318. 

  319.     step = step_table[c->step_index];

  320.     step_index = c->step_index + index_table[(unsigned)nibble];

  321.     if (step_index < 0) step_index = 0;

  322.     else if (step_index > 88) step_index = 88;

  323. 

  324.     sign = nibble & 8;

  325.     delta = nibble & 7;

  326.     

  327.     diff = (delta*step + (step>>1))>>3; // difference to code above

  328.     

  329.     predictor = c->predictor;

  330.     if (sign) predictor -= diff;

  331.     else predictor += diff;

  332. 

  333.     CLAMP_TO_SHORT(predictor);

  334.     c->predictor = predictor;

  335.     c->step_index = step_index;

  336. 

  337.     return (short)predictor;

  338. }

  339. 

  340. static inline short adpcm_ms_expand_nibble(ADPCMChannelStatus *c, char nibble)

  341. {

  342.     int predictor;

  343. 

  344.     predictor = (((c->sample1) * (c->coeff1)) + ((c->sample2) * (c->coeff2))) / 256;

  345.     predictor += (signed)((nibble & 0x08)?(nibble - 0x10):(nibble)) * c->idelta;

  346.     CLAMP_TO_SHORT(predictor);

  347. 

  348.     c->sample2 = c->sample1;

  349.     c->sample1 = predictor;

  350.     c->idelta = (AdaptationTable[(int)nibble] * c->idelta) / 256;

  351.     if (c->idelta < 16) c->idelta = 16;

  352. 

  353.     return (short)predictor;

  354. }

  355. 

  356. /* DK3 ADPCM support macro */

  357. #define DK3_GET_NEXT_NIBBLE() \

  358.     if (decode_top_nibble_next) \

  359.     { \

  360.         nibble = (last_byte >> 4) & 0x0F; \

  361.         decode_top_nibble_next = 0; \

  362.     } \

  363.     else \

  364.     { \

  365.         last_byte = *src++; \

  366.         if (src >= buf + buf_size) break; \

  367.         nibble = last_byte & 0x0F; \

  368.         decode_top_nibble_next = 1; \

  369.     }

  370. 

  371. static int adpcm_decode_frame(AVCodecContext *avctx,

  372. 			    void *data, int *data_size,

  373. 			    uint8_t *buf, int buf_size)

  374. {

  375.     ADPCMContext *c = avctx->priv_data;

  376.     ADPCMChannelStatus *cs;

  377.     int n, m, channel, i;

  378.     int block_predictor[2];

  379.     short *samples;

  380.     uint8_t *src;

  381.     int st; /* stereo */

  382. 

  383.     /* DK3 ADPCM accounting variables */

  384.     unsigned char last_byte = 0;

  385.     unsigned char nibble;

  386.     int decode_top_nibble_next = 0;

  387.     int diff_channel;

  388. 

  389.     samples = data;

  390.     src = buf;

  391. 

  392.     st = avctx->channels == 2;

  393. 

  394.     switch(avctx->codec->id) {

  395.     case CODEC_ID_ADPCM_IMA_QT:

  396.         n = (buf_size - 2);/* >> 2*avctx->channels;*/

  397.         channel = c->channel;

  398.         cs = &(c->status[channel]);

  399.         /* (pppppp) (piiiiiii) */

  400. 

  401.         /* Bits 15-7 are the _top_ 9 bits of the 16-bit initial predictor value */

  402.         cs->predictor = (*src++) << 8;

  403.         cs->predictor |= (*src & 0x80);

  404.         cs->predictor &= 0xFF80;

  405. 

  406.         /* sign extension */

  407.         if(cs->predictor & 0x8000)

  408.             cs->predictor -= 0x10000;

  409. 

  410.         CLAMP_TO_SHORT(cs->predictor);

  411. 

  412.         cs->step_index = (*src++) & 0x7F;

  413. 

  414.         if (cs->step_index > 88) fprintf(stderr, "ERROR: step_index = %i\n", cs->step_index);

  415.         if (cs->step_index > 88) cs->step_index = 88;

  416. 

  417.         cs->step = step_table[cs->step_index];

  418. 

  419.         if (st && channel)

  420.             samples++;

  421. 

  422.         *samples++ = cs->predictor;

  423.         samples += st;

  424. 

  425.         for(m=32; n>0 && m>0; n--, m--) { /* in QuickTime, IMA is encoded by chuncks of 34 bytes (=64 samples) */

  426.             *samples = adpcm_ima_expand_nibble(cs, src[0] & 0x0F);

  427.             samples += avctx->channels;

  428.             *samples = adpcm_ima_expand_nibble(cs, (src[0] >> 4) & 0x0F);

  429.             samples += avctx->channels;

  430.             src ++;

  431.         }

  432. 

  433.         if(st) { /* handle stereo interlacing */

  434.             c->channel = (channel + 1) % 2; /* we get one packet for left, then one for right data */

  435.             if(channel == 0) { /* wait for the other packet before outputing anything */

  436.                 *data_size = 0;

  437.                 return src - buf;

  438.             }

  439.         }

  440.         break;

  441.     case CODEC_ID_ADPCM_IMA_WAV:

  442.         if (buf_size > BLKSIZE) {

  443.             if (avctx->block_align != 0)

  444.                 buf_size = avctx->block_align;

  445.             else

  446.                 buf_size = BLKSIZE;

  447.         }

  448. 	// XXX: do as per-channel loop

  449.         cs = &(c->status[0]);

  450.         cs->predictor = (*src++) & 0x0FF;

  451.         cs->predictor |= ((*src++) << 8) & 0x0FF00;

  452.         if(cs->predictor & 0x8000)

  453.             cs->predictor -= 0x10000;

  454.         CLAMP_TO_SHORT(cs->predictor);

  455. 

  456. 	// XXX: is this correct ??: *samples++ = cs->predictor;

  457. 

  458. 	cs->step_index = *src++;

  459.         if (cs->step_index < 0) cs->step_index = 0;

  460.         if (cs->step_index > 88) cs->step_index = 88;

  461.         if (*src++) fprintf(stderr, "unused byte should be null !!\n"); /* unused */

  462. 

  463.         if (st) {

  464.             cs = &(c->status[1]);

  465.             cs->predictor = (*src++) & 0x0FF;

  466.             cs->predictor |= ((*src++) << 8) & 0x0FF00;

  467.             if(cs->predictor & 0x8000)

  468.                 cs->predictor -= 0x10000;

  469.             CLAMP_TO_SHORT(cs->predictor);

  470. 

  471. 	    // XXX: is this correct ??: *samples++ = cs->predictor;

  472. 

  473. 	    cs->step_index = *src++;

  474.             if (cs->step_index < 0) cs->step_index = 0;

  475.             if (cs->step_index > 88) cs->step_index = 88;

  476.             src++; /* if != 0  -> out-of-sync */

  477.         }

  478. 

  479.         for(m=4; src < (buf + buf_size);) {

  480. 	    *samples++ = adpcm_ima_expand_nibble(&c->status[0], src[0] & 0x0F);

  481.             if (st)

  482.                 *samples++ = adpcm_ima_expand_nibble(&c->status[1], src[4] & 0x0F);

  483.             *samples++ = adpcm_ima_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F);

  484. 	    if (st) {

  485.                 *samples++ = adpcm_ima_expand_nibble(&c->status[1], (src[4] >> 4) & 0x0F);

  486. 		if (!--m) {

  487. 		    m=4;

  488. 		    src+=4;

  489. 		}

  490. 	    }

  491. 	    src++;

  492. 	}

  493.         break;

  494.     case CODEC_ID_ADPCM_4XM:

  495.         cs = &(c->status[0]);

  496.         c->status[0].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;

  497.         if(st){

  498.             c->status[1].predictor= (int16_t)(src[0] + (src[1]<<8)); src+=2;

  499.         }

  500.         c->status[0].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;

  501.         if(st){

  502.             c->status[1].step_index= (int16_t)(src[0] + (src[1]<<8)); src+=2;

  503.         }

  504. //            if (cs->step_index < 0) cs->step_index = 0;

  505. //            if (cs->step_index > 88) cs->step_index = 88;

  506. 

  507.         m= (buf_size - (src - buf))>>st;

  508. //printf("%d %d %d %d\n", st, m, c->status[0].predictor, c->status[0].step_index);

  509.         //FIXME / XXX decode chanels individual & interleave samples

  510.         for(i=0; i<m; i++) {

  511. 	    *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] & 0x0F);

  512.             if (st)

  513.                 *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] & 0x0F);

  514.             *samples++ = adpcm_4xa_expand_nibble(&c->status[0], src[i] >> 4);

  515. 	    if (st)

  516.                 *samples++ = adpcm_4xa_expand_nibble(&c->status[1], src[i+m] >> 4);

  517. 	}

  518. 

  519.         src += m<<st;

  520. 

  521.         break;

  522.     case CODEC_ID_ADPCM_MS:

  523. 

  524.         if (buf_size > BLKSIZE) {

  525.             if (avctx->block_align != 0)

  526.                 buf_size = avctx->block_align;

  527.             else

  528.                 buf_size = BLKSIZE;

  529.         }

  530.         n = buf_size - 7 * avctx->channels;

  531.         if (n < 0)

  532.             return -1;

  533.         block_predictor[0] = (*src++); /* should be bound */

  534.         block_predictor[0] = (block_predictor[0] < 0)?(0):((block_predictor[0] > 7)?(7):(block_predictor[0]));

  535.         block_predictor[1] = 0;

  536.         if (st)

  537.             block_predictor[1] = (*src++);

  538.         block_predictor[1] = (block_predictor[1] < 0)?(0):((block_predictor[1] > 7)?(7):(block_predictor[1]));

  539.         c->status[0].idelta = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));

  540.         if (c->status[0].idelta & 0x08000)

  541.             c->status[0].idelta -= 0x10000;

  542.         src+=2;

  543.         if (st)

  544.             c->status[1].idelta = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));

  545.         if (st && c->status[1].idelta & 0x08000)

  546.             c->status[1].idelta |= 0xFFFF0000;

  547.         if (st)

  548.             src+=2;

  549.         c->status[0].coeff1 = AdaptCoeff1[block_predictor[0]];

  550.         c->status[0].coeff2 = AdaptCoeff2[block_predictor[0]];

  551.         c->status[1].coeff1 = AdaptCoeff1[block_predictor[1]];

  552.         c->status[1].coeff2 = AdaptCoeff2[block_predictor[1]];

  553.         

  554.         c->status[0].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));

  555.         src+=2;

  556.         if (st) c->status[1].sample1 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));

  557.         if (st) src+=2;

  558.         c->status[0].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));

  559.         src+=2;

  560.         if (st) c->status[1].sample2 = ((*src & 0xFF) | ((src[1] << 8) & 0xFF00));

  561.         if (st) src+=2;

  562. 

  563.         *samples++ = c->status[0].sample1;

  564.         if (st) *samples++ = c->status[1].sample1;

  565.         *samples++ = c->status[0].sample2;

  566.         if (st) *samples++ = c->status[1].sample2;

  567.         for(;n>0;n--) {

  568.             *samples++ = adpcm_ms_expand_nibble(&c->status[0], (src[0] >> 4) & 0x0F);

  569.             *samples++ = adpcm_ms_expand_nibble(&c->status[st], src[0] & 0x0F);

  570.             src ++;

  571.         }

  572.         break;

  573.     case CODEC_ID_ADPCM_IMA_DK4:

  574.         if (buf_size > BLKSIZE) {

  575.             if (avctx->block_align != 0)

  576.                 buf_size = avctx->block_align;

  577.             else

  578.                 buf_size = BLKSIZE;

  579.         }

  580.         c->status[0].predictor = (src[0] | (src[1] << 8));

  581.         c->status[0].step_index = src[2];

  582.         src += 4;

  583.         if(c->status[0].predictor & 0x8000)

  584.             c->status[0].predictor -= 0x10000;

  585.         *samples++ = c->status[0].predictor;

  586.         if (st) {

  587.             c->status[1].predictor = (src[0] | (src[1] << 8));

  588.             c->status[1].step_index = src[2];

  589.             src += 4;

  590.             if(c->status[1].predictor & 0x8000)

  591.                 c->status[1].predictor -= 0x10000;

  592.             *samples++ = c->status[1].predictor;

  593.         }

  594.         while (src < buf + buf_size) {

  595. 

  596.             /* take care of the top nibble (always left or mono channel) */

  597.             *samples++ = adpcm_ima_expand_nibble(&c->status[0], 

  598.                 (src[0] >> 4) & 0x0F);

  599. 

  600.             /* take care of the bottom nibble, which is right sample for

  601.              * stereo, or another mono sample */

  602.             if (st)

  603.                 *samples++ = adpcm_ima_expand_nibble(&c->status[1], 

  604.                     src[0] & 0x0F);

  605.             else

  606.                 *samples++ = adpcm_ima_expand_nibble(&c->status[0], 

  607.                     src[0] & 0x0F);

  608. 

  609.             src++;

  610.         }

  611.         break;

  612.     case CODEC_ID_ADPCM_IMA_DK3:

  613.         if (buf_size > BLKSIZE) {

  614.             if (avctx->block_align != 0)

  615.                 buf_size = avctx->block_align;

  616.             else

  617.                 buf_size = BLKSIZE;

  618.         }

  619.         c->status[0].predictor = (src[10] | (src[11] << 8));

  620.         c->status[1].predictor = (src[12] | (src[13] << 8));

  621.         c->status[0].step_index = src[14];

  622.         c->status[1].step_index = src[15];

  623.         /* sign extend the predictors */

  624.         if(c->status[0].predictor & 0x8000)

  625.             c->status[0].predictor -= 0x10000;

  626.         if(c->status[1].predictor & 0x8000)

  627.             c->status[1].predictor -= 0x10000;

  628.         src += 16;

  629.         diff_channel = c->status[1].predictor;

  630. 

  631.         /* the DK3_GET_NEXT_NIBBLE macro issues the break statement when

  632.          * the buffer is consumed */

  633.         while (1) {

  634. 

  635.             /* for this algorithm, c->status[0] is the sum channel and

  636.              * c->status[1] is the diff channel */

  637. 

  638.             /* process the first predictor of the sum channel */

  639.             DK3_GET_NEXT_NIBBLE();

  640.             adpcm_ima_expand_nibble(&c->status[0], nibble);

  641. 

  642.             /* process the diff channel predictor */

  643.             DK3_GET_NEXT_NIBBLE();

  644.             adpcm_ima_expand_nibble(&c->status[1], nibble);

  645. 

  646.             /* process the first pair of stereo PCM samples */

  647.             diff_channel = (diff_channel + c->status[1].predictor) / 2;

  648.             *samples++ = c->status[0].predictor + c->status[1].predictor;

  649.             *samples++ = c->status[0].predictor - c->status[1].predictor;

  650. 

  651.             /* process the second predictor of the sum channel */

  652.             DK3_GET_NEXT_NIBBLE();

  653.             adpcm_ima_expand_nibble(&c->status[0], nibble);

  654. 

  655.             /* process the second pair of stereo PCM samples */

  656.             diff_channel = (diff_channel + c->status[1].predictor) / 2;

  657.             *samples++ = c->status[0].predictor + c->status[1].predictor;

  658.             *samples++ = c->status[0].predictor - c->status[1].predictor;

  659.         }

  660.         break;

  661.     case CODEC_ID_ADPCM_IMA_WS:

  662.         /* no per-block initialization; just start decoding the data */

  663.         while (src < buf + buf_size) {

  664. 

  665.             if (st) {

  666.                 *samples++ = adpcm_ima_expand_nibble(&c->status[0], 

  667.                     (src[0] >> 4) & 0x0F);

  668.                 *samples++ = adpcm_ima_expand_nibble(&c->status[1], 

  669.                     src[0] & 0x0F);

  670.             } else {

  671.                 *samples++ = adpcm_ima_expand_nibble(&c->status[0], 

  672.                     (src[0] >> 4) & 0x0F);

  673.                 *samples++ = adpcm_ima_expand_nibble(&c->status[0], 

  674.                     src[0] & 0x0F);

  675.             }

  676. 

  677.             src++;

  678.         }

  679.         break;

  680.     default:

  681.         *data_size = 0;

  682.         return -1;

  683.     }

  684.     *data_size = (uint8_t *)samples - (uint8_t *)data;

  685.     return src - buf;

  686. }

  687. 

  688. #define ADPCM_CODEC(id, name)                   \

  689. AVCodec name ## _encoder = {                    \

  690.     #name,                                      \

  691.     CODEC_TYPE_AUDIO,                           \

  692.     id,                                         \

  693.     sizeof(ADPCMContext),                       \

  694.     adpcm_encode_init,                          \

  695.     adpcm_encode_frame,                         \

  696.     adpcm_encode_close,                         \

  697.     NULL,                                       \

  698. };                                              \

  699. AVCodec name ## _decoder = {                    \

  700.     #name,                                      \

  701.     CODEC_TYPE_AUDIO,                           \

  702.     id,                                         \

  703.     sizeof(ADPCMContext),                       \

  704.     adpcm_decode_init,                          \

  705.     NULL,                                       \

  706.     NULL,                                       \

  707.     adpcm_decode_frame,                         \

  708. };

  709. 

  710. ADPCM_CODEC(CODEC_ID_ADPCM_IMA_QT, adpcm_ima_qt);

  711. ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WAV, adpcm_ima_wav);

  712. ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK3, adpcm_ima_dk3);

  713. ADPCM_CODEC(CODEC_ID_ADPCM_IMA_DK4, adpcm_ima_dk4);

  714. ADPCM_CODEC(CODEC_ID_ADPCM_IMA_WS, adpcm_ima_ws);

  715. ADPCM_CODEC(CODEC_ID_ADPCM_MS, adpcm_ms);

  716. ADPCM_CODEC(CODEC_ID_ADPCM_4XM, adpcm_4xm);

  717. 

  718. #undef ADPCM_CODEC