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32 lines
1.0 KiB
C
32 lines
1.0 KiB
C
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#include "adx.h"
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#include "../util.h"
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void decode_adx(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
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int i=first_sample;
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int32_t sample_count;
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int32_t scale = read_16bitBE(stream->offset,stream->streamfile) + 1;
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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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int coef1 = stream->adpcm_coef[0];
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int coef2 = stream->adpcm_coef[1];
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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(stream->offset+2+i/2,stream->streamfile);
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outbuf[sample_count] = clamp16(
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(i&1?
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get_low_nibble_signed(sample_byte):
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get_high_nibble_signed(sample_byte)
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) * scale +
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((coef1 * hist1 + coef2 * hist2) >> 12)
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);
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hist2 = hist1;
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hist1 = outbuf[sample_count];
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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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