diff options
Diffstat (limited to 'lib/rbcodec/codecs/libpcm/ms_adpcm.c')
| -rw-r--r-- | lib/rbcodec/codecs/libpcm/ms_adpcm.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libpcm/ms_adpcm.c b/lib/rbcodec/codecs/libpcm/ms_adpcm.c new file mode 100644 index 0000000000..a385d6c99f --- /dev/null +++ b/lib/rbcodec/codecs/libpcm/ms_adpcm.c @@ -0,0 +1,168 @@ +/*************************************************************************** + * __________ __ ___. + * Open \______ \ ____ ____ | | _\_ |__ _______ ___ + * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / + * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < + * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ + * \/ \/ \/ \/ \/ + * $Id$ + * + * Copyright (C) 2010 Yoshihisa Uchida + * + * 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 "support_formats.h" + +/* + * Microsoft ADPCM + * + * References + * [1] Microsoft, New Multimedia Data Types and Data Techniques Revision 3.0, 1994 + * [2] MulitimediaWiki, Microsoft ADPCM, 2006 + * (http://wiki.multimedia.cx/index.php?title=Microsoft_ADPCM) + * [3] ffmpeg source code, libavcodec/adpcm.c + */ + +#define ADPCM_NUM_COEFF 7 + +static int16_t dec_coeff[2][2]; +static uint16_t delta[2]; +static int16_t sample[2][2]; + +static struct pcm_format *fmt; + +static const int16_t adaptation_table[] ICONST_ATTR = { + 230, 230, 230, 230, 307, 409, 512, 614, + 768, 614, 512, 409, 307, 230, 230, 230 +}; + +static bool set_format(struct pcm_format *format) +{ + fmt = format; + + if (fmt->bitspersample != 4) + { + DEBUGF("CODEC_ERROR: microsoft adpcm must be 4 bitspersample: %d\n", + fmt->bitspersample); + return false; + } + + fmt->chunksize = fmt->blockalign; + + return true; +} + +static struct pcm_pos *get_seek_pos(uint32_t seek_val, int seek_mode, + uint8_t *(*read_buffer)(size_t *realsize)) +{ + static struct pcm_pos newpos; + uint32_t newblock = (seek_mode == PCM_SEEK_TIME) ? + ((uint64_t)seek_val * ci->id3->frequency / 1000LL) + / fmt->samplesperblock : + seek_val / fmt->blockalign; + + (void)read_buffer; + newpos.pos = newblock * fmt->blockalign; + newpos.samples = newblock * fmt->samplesperblock; + return &newpos; +} + +static int16_t create_pcmdata(int ch, uint8_t nibble) +{ + int32_t pcmdata; + + pcmdata = (sample[ch][0] * dec_coeff[ch][0] + + sample[ch][1] * dec_coeff[ch][1]) / 256; + pcmdata += (delta[ch] * (nibble - ((nibble & 0x8) << 1))); + + CLIP(pcmdata, -32768, 32767); + + sample[ch][1] = sample[ch][0]; + sample[ch][0] = pcmdata; + + delta[ch] = (adaptation_table[nibble] * delta[ch]) >> 8; + if (delta[ch] < 16) + delta[ch] = 16; + + return (int16_t)pcmdata; +} + +static int decode(const uint8_t *inbuf, size_t inbufsize, + int32_t *outbuf, int *outbufcount) +{ + int ch; + size_t nsamples = 0; + int size = fmt->samplesperblock; + + /* read block header */ + for (ch = 0; ch < fmt->channels; ch++) + { + if (*inbuf >= ADPCM_NUM_COEFF) + { + DEBUGF("CODEC_ERROR: microsoft adpcm illegal initial coeff=%d > 7\n", + *inbuf); + return CODEC_ERROR; + } + dec_coeff[ch][0] = fmt->coeffs[*inbuf][0]; + dec_coeff[ch][1] = fmt->coeffs[*inbuf][1]; + inbuf++; + } + + for (ch = 0; ch < fmt->channels; ch++) + { + delta[ch] = inbuf[0] | (SE(inbuf[1]) << 8); + inbuf += 2; + } + + for (ch = 0; ch < fmt->channels; ch++) + { + sample[ch][0] = inbuf[0] | (SE(inbuf[1]) << 8); + inbuf += 2; + } + + for (ch = 0; ch < fmt->channels; ch++) + { + sample[ch][1] = inbuf[0] | (SE(inbuf[1]) << 8); + inbuf += 2; + } + + inbufsize -= 7 * fmt->channels; + ch = fmt->channels - 1; + + while (size-- > 0) + { + *outbuf++ = create_pcmdata(0, *inbuf >> 4 ) << (PCM_OUTPUT_DEPTH - 16); + *outbuf++ = create_pcmdata(ch, *inbuf & 0xf) << (PCM_OUTPUT_DEPTH - 16); + nsamples += 2; + + inbuf++; + inbufsize--; + if (inbufsize <= 0) + break; + } + + if (fmt->channels == 2) + nsamples >>= 1; + *outbufcount = nsamples; + + return CODEC_OK; +} + +static const struct pcm_codec codec = { + set_format, + get_seek_pos, + decode, + }; + +const struct pcm_codec *get_ms_adpcm_codec(void) +{ + return &codec; +} |