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https://github.com/vgmstream/vgmstream.git
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2a686eeea2
git-svn-id: https://vgmstream.svn.sourceforge.net/svnroot/vgmstream@89 51a99a44-fe44-0410-b1ba-c3e57ba2b86b
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
#include "coding.h"
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#include "../util.h"
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void decode_ngc_dtk(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int channel) {
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int i=first_sample;
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int32_t sample_count;
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int framesin = first_sample/28;
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uint8_t q = read_8bit(framesin*32+stream->offset+channel,stream->streamfile);
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int32_t hist1 = stream->adpcm_history1_32;
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int32_t hist2 = stream->adpcm_history2_32;
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first_sample = first_sample%28;
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for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
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int sample_byte = read_8bit(framesin*32+stream->offset+4+i,stream->streamfile);
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int32_t hist=0;
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switch (q>>4)
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{
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case 0:
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hist = 0;
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break;
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case 1:
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hist = (hist1 * 0x3c);
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break;
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case 2:
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hist = (hist1 * 0x73) - (hist2 * 0x34);
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break;
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case 3:
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hist = (hist1 * 0x62) - (hist2 * 0x37);
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break;
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}
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hist = (hist+0x20)>>6;
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if (hist > 0x1fffff) hist = 0x1fffff;
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if (hist < -0x200000) hist = -0x200000;
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hist2 = hist1;
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hist1 = ((((channel==0?
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get_low_nibble_signed(sample_byte):
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get_high_nibble_signed(sample_byte)
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) << 12) >> (q & 0xf)) << 6) + hist;
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outbuf[sample_count] = clamp16(hist1 >> 6);
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}
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stream->adpcm_history1_32 = hist1;
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stream->adpcm_history2_32 = hist2;
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}
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