/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * $Id$ * * Copyright (C) 2005 Dave Chapman * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ #include "codeclib.h" #include "inttypes.h" CODEC_HEADER /* Macro that sign extends an unsigned byte */ #define SE(x) ((int32_t)((int8_t)(x))) /* This codec support WAVE files with the following formats: * - PCM, up to 32 bits, supporting 32 bits playback when useful. * - ALAW and MULAW (16 bits compressed on 8 bits). * - DVI_ADPCM (16 bits compressed on 3 or 4 bits). * * For a good documentation on WAVE files, see: * http://www.tsp.ece.mcgill.ca/MMSP/Documents/AudioFormats/WAVE/WAVE.html * and * http://www.sonicspot.com/guide/wavefiles.html * * For sample WAV files, see: * http://www.tsp.ece.mcgill.ca/MMSP/Documents/AudioFormats/WAVE/Samples.html * * The most common formats seem to be PCM, ADPCM, DVI_ADPCM, IEEE_FLOAT, * ALAW and MULAW */ /* These constants are from RFC 2361. */ enum { WAVE_FORMAT_UNKNOWN = 0x0000, /* Microsoft Unknown Wave Format */ WAVE_FORMAT_PCM = 0x0001, /* Microsoft PCM Format */ WAVE_FORMAT_ADPCM = 0x0002, /* Microsoft ADPCM Format */ WAVE_FORMAT_IEEE_FLOAT = 0x0003, /* IEEE Float */ WAVE_FORMAT_VSELP = 0x0004, /* Compaq Computer's VSELP */ WAVE_FORMAT_IBM_CVSD = 0x0005, /* IBM CVSD */ WAVE_FORMAT_ALAW = 0x0006, /* Microsoft ALAW */ WAVE_FORMAT_MULAW = 0x0007, /* Microsoft MULAW */ WAVE_FORMAT_OKI_ADPCM = 0x0010, /* OKI ADPCM */ WAVE_FORMAT_DVI_ADPCM = 0x0011, /* Intel's DVI ADPCM */ WAVE_FORMAT_MEDIASPACE_ADPCM = 0x0012, /* Videologic's MediaSpace ADPCM */ WAVE_FORMAT_SIERRA_ADPCM = 0x0013, /* Sierra ADPCM */ WAVE_FORMAT_G723_ADPCM = 0x0014, /* G.723 ADPCM */ WAVE_FORMAT_DIGISTD = 0x0015, /* DSP Solutions' DIGISTD */ WAVE_FORMAT_DIGIFIX = 0x0016, /* DSP Solutions' DIGIFIX */ WAVE_FORMAT_DIALOGIC_OKI_ADPCM = 0x0017, /* Dialogic OKI ADPCM */ WAVE_FORMAT_MEDIAVISION_ADPCM = 0x0018, /* MediaVision ADPCM */ WAVE_FORMAT_CU_CODEC = 0x0019, /* HP CU */ WAVE_FORMAT_YAMAHA_ADPCM = 0x0020, /* Yamaha ADPCM */ WAVE_FORMAT_SONARC = 0x0021, /* Speech Compression's Sonarc */ WAVE_FORMAT_DSP_TRUESPEECH = 0x0022, /* DSP Group's True Speech */ WAVE_FORMAT_ECHOSC1 = 0x0023, /* Echo Speech's EchoSC1 */ WAVE_FORMAT_AUDIOFILE_AF36 = 0x0024, /* Audiofile AF36 */ WAVE_FORMAT_APTX = 0x0025, /* APTX */ WAVE_FORMAT_DOLBY_AC2 = 0x0030, /* Dolby AC2 */ WAVE_FORMAT_GSM610 = 0x0031, /* GSM610 */ WAVE_FORMAT_MSNAUDIO = 0x0032, /* MSNAudio */ WAVE_FORMAT_ANTEX_ADPCME = 0x0033, /* Antex ADPCME */ WAVE_FORMAT_MPEG = 0x0050, /* MPEG */ WAVE_FORMAT_MPEGLAYER3 = 0x0055, /* MPEG layer 3 */ WAVE_FORMAT_LUCENT_G723 = 0x0059, /* Lucent G.723 */ WAVE_FORMAT_G726_ADPCM = 0x0064, /* G.726 ADPCM */ WAVE_FORMAT_G722_ADPCM = 0x0065, /* G.722 ADPCM */ IBM_FORMAT_MULAW = 0x0101, /* same as WAVE_FORMAT_MULAW */ IBM_FORMAT_ALAW = 0x0102, /* same as WAVE_FORMAT_ALAW */ IBM_FORMAT_ADPCM = 0x0103, WAVE_FORMAT_CREATIVE_ADPCM = 0x0200, WAVE_FORMAT_EXTENSIBLE = 0xFFFE }; /* Maximum number of bytes to process in one iteration */ /* for 44.1kHz stereo 16bits, this represents 0.023s ~= 1/50s */ #define WAV_CHUNK_SIZE (1024*2) static const int16_t alaw2linear16[256] ICONST_ATTR = { -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736, -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784, -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368, -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392, -22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944, -30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136, -11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472, -15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568, -344, -328, -376, -360, -280, -264, -312, -296, -472, -456, -504, -488, -408, -392, -440, -424, -88, -72, -120, -104, -24, -8, -56, -40, -216, -200, -248, -232, -152, -136, -184, -168, -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184, -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696, -688, -656, -752, -720, -560, -528, -624, -592, -944, -912, -1008, -976, -816, -784, -880, -848, 5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736, 7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784, 2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368, 3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392, 22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944, 30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136, 11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472, 15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568, 344, 328, 376, 360, 280, 264, 312, 296, 472, 456, 504, 488, 408, 392, 440, 424, 88, 72, 120, 104, 24, 8, 56, 40, 216, 200, 248, 232, 152, 136, 184, 168, 1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184, 1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696, 688, 656, 752, 720, 560, 528, 624, 592, 944, 912, 1008, 976, 816, 784, 880, 848 }; static const int16_t ulaw2linear16[256] ICONST_ATTR = { -32124, -31100, -30076, -29052, -28028, -27004, -25980, -24956, -23932, -22908, -21884, -20860, -19836, -18812, -17788, -16764, -15996, -15484, -14972, -14460, -13948, -13436, -12924, -12412, -11900, -11388, -10876, -10364, -9852, -9340, -8828, -8316, -7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140, -5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092, -3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004, -2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980, -1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436, -1372, -1308, -1244, -1180, -1116, -1052, -988, -924, -876, -844, -812, -780, -748, -716, -684, -652, -620, -588, -556, -524, -492, -460, -428, -396, -372, -356, -340, -324, -308, -292, -276, -260, -244, -228, -212, -196, -180, -164, -148, -132, -120, -112, -104, -96, -88, -80, -72, -64, -56, -48, -40, -32, -24, -16, -8, 0, 32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956, 23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764, 15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412, 11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316, 7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140, 5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092, 3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004, 2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980, 1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436, 1372, 1308, 1244, 1180, 1116, 1052, 988, 924, 876, 844, 812, 780, 748, 716, 684, 652, 620, 588, 556, 524, 492, 460, 428, 396, 372, 356, 340, 324, 308, 292, 276, 260, 244, 228, 212, 196, 180, 164, 148, 132, 120, 112, 104, 96, 88, 80, 72, 64, 56, 48, 40, 32, 24, 16, 8, 0 }; static const uint16_t dvi_adpcm_steptab[89] ICONST_ATTR = { 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 19, 21, 23, 25, 28, 31, 34, 37, 41, 45, 50, 55, 60, 66, 73, 80, 88, 97, 107, 118, 130, 143, 157, 173, 190, 209, 230, 253, 279, 307, 337, 371, 408, 449, 494, 544, 598, 658, 724, 796, 876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767 }; static const int dvi_adpcm_indextab4[8] ICONST_ATTR = { -1, -1, -1, -1, 2, 4, 6, 8 }; static const int dvi_adpcm_indextab3[4] ICONST_ATTR = { -1, -1, 1, 2 }; static int32_t samples[WAV_CHUNK_SIZE] IBSS_ATTR; static enum codec_status decode_dvi_adpcm(struct codec_api *ci, const uint8_t *buf, int n, uint16_t channels, uint16_t bitspersample, int32_t *pcmout, size_t *pcmoutsize); /* this is the codec entry point */ enum codec_status codec_main(void) { uint32_t numbytes, bytesdone; uint32_t totalsamples = 0; uint16_t channels = 0; uint16_t samplesperblock = 0; int bytespersample = 0; uint16_t bitspersample; uint32_t i; size_t n; int bufcount; int endofstream; unsigned char *buf; uint8_t *wavbuf; long chunksize; uint16_t formattag = 0; uint16_t blockalign = 0; uint32_t avgbytespersec = 0; off_t firstblockposn; /* position of the first block in file */ /* Generic codec initialisation */ ci->configure(DSP_SET_SAMPLE_DEPTH, 28); ci->configure(CODEC_SET_FILEBUF_WATERMARK, 1024*512); next_track: if (codec_init()) { i = CODEC_ERROR; goto exit; } while (!*ci->taginfo_ready && !ci->stop_codec) ci->sleep(1); codec_set_replaygain(ci->id3); /* Need to save offset for later use (cleared indirectly by advance_buffer) */ bytesdone = ci->id3->offset; /* get RIFF chunk header */ buf = ci->request_buffer(&n, 12); if (n < 12) { i = CODEC_ERROR; goto done; } if ((memcmp(buf, "RIFF", 4) != 0) || (memcmp(&buf[8], "WAVE", 4) != 0)) { i = CODEC_ERROR; goto done; } /* advance to first WAVE chunk */ ci->advance_buffer(12); firstblockposn = 12; bitspersample = 0; numbytes = 0; totalsamples = 0; /* iterate over WAVE chunks until the 'data' chunk, which should be after the 'fmt ' chunk */ while (true) { /* get WAVE chunk header */ buf = ci->request_buffer(&n, 1024); if (n < 8) { /* no more chunks, 'data' chunk must not have been found */ i = CODEC_ERROR; goto done; } /* chunkSize */ i = (buf[4]|(buf[5]<<8)|(buf[6]<<16)|(buf[7]<<24)); if (memcmp(buf, "fmt ", 4) == 0) { if (i < 16) { DEBUGF("CODEC_ERROR: 'fmt ' chunk size=%lu < 16\n", (unsigned long)i); i = CODEC_ERROR; goto done; } /* wFormatTag */ formattag=buf[8]|(buf[9]<<8); /* wChannels */ channels=buf[10]|(buf[11]<<8); /* skipping dwSamplesPerSec */ /* dwAvgBytesPerSec */ avgbytespersec = buf[16]|(buf[17]<<8)|(buf[18]<<16)|(buf[19]<<24); /* wBlockAlign */ blockalign=buf[20]|(buf[21]<<8); /* wBitsPerSample */ bitspersample=buf[22]|(buf[23]<<8); if (formattag != WAVE_FORMAT_PCM) { uint16_t size; if (i < 18) { /* this is not a fatal error with some formats, * we'll see later if we can't decode it */ DEBUGF("CODEC_WARNING: non-PCM WAVE (formattag=0x%x) " "doesn't have ext. fmt descr (chunksize=%ld<18).\n", formattag, (long)i); } size = buf[24]|(buf[25]<<8); if (formattag == WAVE_FORMAT_DVI_ADPCM) { if (size < 2) { DEBUGF("CODEC_ERROR: dvi_adpcm is missing " "SamplesPerBlock value\n"); i = CODEC_ERROR; goto done; } samplesperblock = buf[26]|(buf[27]<<8); } else if (formattag == WAVE_FORMAT_EXTENSIBLE) { if (size < 22) { DEBUGF("CODEC_ERROR: WAVE_FORMAT_EXTENSIBLE is " "missing extension\n"); i = CODEC_ERROR; goto done; } /* wValidBitsPerSample */ bitspersample = buf[26]|(buf[27]<<8); /* skipping dwChannelMask (4bytes) */ /* SubFormat (only get the first two bytes) */ formattag = buf[32]|(buf[33]<<8); } } } else if (memcmp(buf, "data", 4) == 0) { numbytes = i; /* advance to start of data */ ci->advance_buffer(8); firstblockposn += 8; break; } else if (memcmp(buf, "fact", 4) == 0) { /* dwSampleLength */ if (i >= 4) totalsamples = (buf[8]|(buf[9]<<8)|(buf[10]<<16)|(buf[11]<<24)); } else { DEBUGF("unknown WAVE chunk: '%c%c%c%c', size=%lu\n", buf[0], buf[1], buf[2], buf[3], (unsigned long)i); } /* go to next chunk (even chunk sizes must be padded) */ if (i & 0x01) i++; ci->advance_buffer(i+8); firstblockposn += i + 8; } if (channels == 0) { DEBUGF("CODEC_ERROR: 'fmt ' chunk not found or 0-channels file\n"); i = CODEC_ERROR; goto done; } if (numbytes == 0) { DEBUGF("CODEC_ERROR: 'data' chunk not found or has zero-length\n"); i = CODEC_ERROR; goto done; } if (formattag != WAVE_FORMAT_PCM && totalsamples == 0) { /* This is non-fatal for some formats */ DEBUGF("CODEC_WARNING: non-PCM WAVE doesn't have a 'fact' chunk\n"); } if (formattag == WAVE_FORMAT_ALAW || formattag == WAVE_FORMAT_MULAW || formattag == IBM_FORMAT_ALAW || formattag == IBM_FORMAT_MULAW) { if (bitspersample != 8) { DEBUGF("CODEC_ERROR: alaw and mulaw must have 8 bitspersample\n"); i = CODEC_ERROR; goto done; } bytespersample = channels; } if (formattag == WAVE_FORMAT_DVI_ADPCM && bitspersample != 4 && bitspersample != 3) { DEBUGF("CODEC_ERROR: dvi_adpcm must have 3 or 4 bitspersample\n"); i = CODEC_ERROR; goto done; } if (formattag == WAVE_FORMAT_PCM && bitspersample > 32) { DEBUGF("CODEC_ERROR: pcm with more than 32 bitspersample " "is unsupported\n"); i = CODEC_ERROR; goto done; } ci->configure(DSP_SWITCH_FREQUENCY, ci->id3->frequency); if (channels == 2) { ci->configure(DSP_SET_STEREO_MODE, STEREO_INTERLEAVED); } else if (channels == 1) { ci->configure(DSP_SET_STEREO_MODE, STEREO_MONO); } else { DEBUGF("CODEC_ERROR: more than 2 channels\n"); i = CODEC_ERROR; goto done; } if (totalsamples == 0) { if (formattag == WAVE_FORMAT_PCM || formattag == WAVE_FORMAT_ALAW || formattag == WAVE_FORMAT_MULAW || formattag == IBM_FORMAT_ALAW || formattag == IBM_FORMAT_MULAW) { /* for PCM and derived formats only */ bytespersample = (((bitspersample - 1)/8 + 1)*channels); totalsamples = numbytes/bytespersample; } else { DEBUGF("CODEC_ERROR: cannot compute totalsamples\n"); i = CODEC_ERROR; goto done; } } /* make sure we're at the correct offset */ if (bytesdone > (uint32_t) firstblockposn) { /* Round down to previous block */ uint32_t offset = bytesdone - bytesdone % blockalign; ci->advance_buffer(offset-firstblockposn); bytesdone = offset - firstblockposn; } else { /* already where we need to be */ bytesdone = 0; } /* The main decoder loop */ endofstream = 0; /* chunksize is computed so that one chunk is about 1/50s. * this make 4096 for 44.1kHz 16bits stereo. * It also has to be a multiple of blockalign */ chunksize = (1 + avgbytespersec / (50*blockalign))*blockalign; /* check that the output buffer is big enough (convert to samplespersec, then round to the blockalign multiple below) */ if (((uint64_t)chunksize*ci->id3->frequency*channels*2) /(uint64_t)avgbytespersec >= WAV_CHUNK_SIZE) { chunksize = ((uint64_t)WAV_CHUNK_SIZE*avgbytespersec /((uint64_t)ci->id3->frequency*channels*2 *blockalign))*blockalign; } while (!endofstream) { ci->yield(); if (ci->stop_codec || ci->new_track) { break; } if (ci->seek_time) { uint32_t newpos; /* use avgbytespersec to round to the closest blockalign multiple, add firstblockposn. 64-bit casts to avoid overflows. */ newpos = (((uint64_t)avgbytespersec*(ci->seek_time - 1)) / (1000LL*blockalign))*blockalign; if (newpos > numbytes) break; if (ci->seek_buffer(firstblockposn + newpos)) bytesdone = newpos; ci->seek_complete(); } wavbuf = (uint8_t *)ci->request_buffer(&n, chunksize); if (n == 0) break; /* End of stream */ if (bytesdone + n > numbytes) { n = numbytes - bytesdone; endofstream = 1; } if (formattag == WAVE_FORMAT_PCM) { if (bitspersample > 24) { for (i = 0; i < n; i += 4) { samples[i/4] = (wavbuf[i] >> 3)| (wavbuf[i + 1]<<5)|(wavbuf[i + 2]<<13)| (SE(wavbuf[i + 3])<<21); } bufcount = n >> 2; } else if (bitspersample > 16) { for (i = 0; i < n; i += 3) { samples[i/3] = (wavbuf[i]<<5)| (wavbuf[i + 1]<<13)|(SE(wavbuf[i + 2])<<21); } bufcount = n/3; } else if (bitspersample > 8) { for (i = 0; i < n; i += 2) { samples[i/2] = (wavbuf[i]<<13)|(SE(wavbuf[i + 1])<<21); } bufcount = n >> 1; } else { for (i = 0; i < n; i++) { samples[i] = (wavbuf[i] - 0x80)<<21; } bufcount = n; } if (channels == 2) bufcount >>= 1; } else if (formattag == WAVE_FORMAT_ALAW || formattag == IBM_FORMAT_ALAW) { for (i = 0; i < n; i++) samples[i] = alaw2linear16[wavbuf[i]] << 13; bufcount = (channels == 2) ? (n >> 1) : n; } else if (formattag == WAVE_FORMAT_MULAW || formattag == IBM_FORMAT_MULAW) { for (i = 0; i < n; i++) samples[i] = ulaw2linear16[wavbuf[i]] << 13; bufcount = (channels == 2) ? (n >> 1) : n; } else if (formattag == WAVE_FORMAT_DVI_ADPCM) { unsigned int nblocks = chunksize/blockalign; for (i = 0; i < nblocks; i++) { size_t decodedsize = samplesperblock*channels; if (decode_dvi_adpcm(ci, wavbuf + i*blockalign, blockalign, channels, bitspersample, samples + i*samplesperblock*channels, &decodedsize) != CODEC_OK) { i = CODEC_ERROR; goto done; } } bufcount = nblocks*samplesperblock; } else { DEBUGF("CODEC_ERROR: unsupported format %x\n", formattag); i = CODEC_ERROR; goto done; } ci->pcmbuf_insert(samples, NULL, bufcount); ci->advance_buffer(n); bytesdone += n; if (bytesdone >= numbytes) endofstream = 1; ci->set_elapsed(bytesdone*1000LL/avgbytespersec); } i = CODEC_OK; done: if (ci->request_next_track()) goto next_track; exit: return i; } static enum codec_status decode_dvi_adpcm(struct codec_api *ci, const uint8_t *buf, int n, uint16_t channels, uint16_t bitspersample, int32_t *pcmout, size_t *pcmoutsize) { size_t nsamples = 0; int sample[2]; int samplecode[32][2]; int i; int stepindex[2]; int c; int diff; int step; int codem; int code; (void)ci; if (bitspersample != 4 && bitspersample != 3) { DEBUGF("decode_dvi_adpcm: wrong bitspersample\n"); return CODEC_ERROR; } /* decode block header */ for (c = 0; c < channels && n >= 4; c++) { /* decode + push first sample */ sample[c] = (short)(buf[0]|(buf[1]<<8));/* need cast for sign-extend */ pcmout[c] = sample[c] << 13; nsamples++; stepindex[c] = buf[2]; /* check for step table index overflow */ if (stepindex[c] > 88) { DEBUGF("decode_dvi_adpcm: stepindex[%d]=%d>88\n",c,stepindex[c]); return CODEC_ERROR; } buf += 4; n -= 4; } if (bitspersample == 4) { while (n>= channels*4 && (nsamples + 8*channels) <= *pcmoutsize) { for (c = 0; c < channels; c++) { samplecode[0][c] = buf[0]&0xf; samplecode[1][c] = buf[0]>>4; samplecode[2][c] = buf[1]&0xf; samplecode[3][c] = buf[1]>>4; samplecode[4][c] = buf[2]&0xf; samplecode[5][c] = buf[2]>>4; samplecode[6][c] = buf[3]&0xf; samplecode[7][c] = buf[3]>>4; buf += 4; n -= 4; } for (i = 0; i < 8; i++) { for (c = 0; c < channels; c++) { step = dvi_adpcm_steptab[stepindex[c]]; codem = samplecode[i][c]; code = codem & 0x07; /* adjust the step table index */ stepindex[c] += dvi_adpcm_indextab4[code]; /* check for step table index overflow and underflow */ if (stepindex[c] > 88) stepindex[c] = 88; else if (stepindex[c] < 0) stepindex[c] = 0; /* calculate the difference */ #ifdef STRICT_IMA diff = 0; if (code & 4) diff += step; step = step >> 1; if (code & 2) diff += step; step = step >> 1; if (code & 1) diff += step; step = step >> 1; diff += step; #else diff = ((code + code + 1) * step) >> 3; /* faster */ #endif /* check the sign bit */ /* check for overflow and underflow errors */ if (code != codem) { sample[c] -= diff; if (sample[c] < -32768) sample[c] = -32768; } else { sample[c] += diff; if (sample[c] > 32767) sample[c] = 32767; } /* output the new sample */ pcmout[nsamples] = sample[c] << 13; nsamples++; } } } } else { /* bitspersample == 3 */ while (n >= channels*12 && (nsamples + 32*channels) <= *pcmoutsize) { for (c = 0; c < channels; c++) { uint16_t bitstream = 0; int bitsread = 0; for (i = 0; i < 32 && n > 0; i++) { if (bitsread < 3) { /* read 8 more bits */ bitstream |= buf[0]<>3; bitsread -= 3; } if (bitsread != 0) { /* 32*3 = 3 words, so we should end with bitsread==0 */ DEBUGF("decode_dvi_adpcm: error in implementation\n"); return CODEC_ERROR; } } for (i = 0; i < 32; i++) { for (c = 0; c < channels; c++) { step = dvi_adpcm_steptab[stepindex[c]]; codem = samplecode[i][c]; code = codem & 0x03; /* adjust the step table index */ stepindex[c] += dvi_adpcm_indextab3[code]; /* check for step table index overflow and underflow */ if (stepindex[c] > 88) stepindex[c] = 88; else if (stepindex[c] < 0) stepindex[c] = 0; /* calculate the difference */ #ifdef STRICT_IMA diff = 0; if (code & 2) diff += step; step = step >> 1; if (code & 1) diff += step; step = step >> 1; diff += step; #else diff = ((code + code + 1) * step) >> 3; /* faster */ #endif /* check the sign bit */ /* check for overflow and underflow errors */ if (code != codem) { sample[c] -= diff; if (sample[c] < -32768) sample[c] = -32768; } else { sample[c] += diff; if (sample[c] > 32767) sample[c] = 32767; } /* output the new sample */ pcmout[nsamples] = sample[c] << 13; nsamples++; } } } } if (nsamples > *pcmoutsize) { DEBUGF("decode_dvi_adpcm: output buffer overflow!\n"); return CODEC_ERROR; } *pcmoutsize = nsamples; if (n != 0) { DEBUGF("decode_dvi_adpcm: n=%d unprocessed bytes\n", n); } return CODEC_OK; }