vgmstream/src/coding/adx_decoder.c
halleyscometsw 2a686eeea2 consolidate headers
git-svn-id: https://vgmstream.svn.sourceforge.net/svnroot/vgmstream@89 51a99a44-fe44-0410-b1ba-c3e57ba2b86b
2008-05-06 03:35:37 +00:00

36 lines
1.1 KiB
C

#include "coding.h"
#include "../util.h"
void decode_adx(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
int i;
int32_t sample_count;
int framesin = first_sample/32;
int32_t scale = read_16bitBE(stream->offset+framesin*18,stream->streamfile) + 1;
int32_t hist1 = stream->adpcm_history1_32;
int32_t hist2 = stream->adpcm_history2_32;
int coef1 = stream->adpcm_coef[0];
int coef2 = stream->adpcm_coef[1];
first_sample = first_sample%32;
for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
int sample_byte = read_8bit(stream->offset+framesin*18+2+i/2,stream->streamfile);
outbuf[sample_count] = clamp16(
(i&1?
get_low_nibble_signed(sample_byte):
get_high_nibble_signed(sample_byte)
) * scale +
((coef1 * hist1 + coef2 * hist2) >> 12)
);
hist2 = hist1;
hist1 = outbuf[sample_count];
}
stream->adpcm_history1_32 = hist1;
stream->adpcm_history2_32 = hist2;
}