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https://github.com/vgmstream/vgmstream.git
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ec94c0d3c5
git-svn-id: https://vgmstream.svn.sourceforge.net/svnroot/vgmstream@316 51a99a44-fe44-0410-b1ba-c3e57ba2b86b
107 lines
3.7 KiB
C
107 lines
3.7 KiB
C
#include "coding.h"
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#include "../util.h"
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void decode_ngc_dsp(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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int framesin = first_sample/14;
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int8_t header = read_8bit(framesin*8+stream->offset,stream->streamfile);
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int32_t scale = 1 << (header & 0xf);
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int coef_index = (header >> 4) & 0xf;
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int32_t hist1 = stream->adpcm_history1_16;
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int32_t hist2 = stream->adpcm_history2_16;
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int coef1 = stream->adpcm_coef[coef_index*2];
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int coef2 = stream->adpcm_coef[coef_index*2+1];
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first_sample = first_sample%14;
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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*8+stream->offset+1+i/2,stream->streamfile);
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#ifdef DEBUG
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if (hist1==stream->loop_history1 && hist2==stream->loop_history2) fprintf(stderr,"yo! %#x (start %#x) %d\n",stream->offset+framesin*8+i/2,stream->channel_start_offset,stream->samples_done);
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stream->samples_done++;
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#endif
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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)<<11) + 1024 +
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(coef1 * hist1 + coef2 * hist2))>>11
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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_16 = hist1;
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stream->adpcm_history2_16 = hist2;
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}
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/* read from memory rather than a file */
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void decode_ngc_dsp_mem(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, uint8_t * mem) {
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int i=first_sample;
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int32_t sample_count;
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int framesin = first_sample/14;
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int8_t header = mem[framesin*8];
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int32_t scale = 1 << (header & 0xf);
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int coef_index = (header >> 4) & 0xf;
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int32_t hist1 = stream->adpcm_history1_16;
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int32_t hist2 = stream->adpcm_history2_16;
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int coef1 = stream->adpcm_coef[coef_index*2];
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int coef2 = stream->adpcm_coef[coef_index*2+1];
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first_sample = first_sample%14;
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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 = mem[framesin*8+1+i/2];
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#ifdef DEBUG
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if (hist1==stream->loop_history1 && hist2==stream->loop_history2) fprintf(stderr,"yo! %#x (start %#x) %d\n",stream->offset+framesin*8+i/2,stream->channel_start_offset,stream->samples_done);
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stream->samples_done++;
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#endif
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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)<<11) + 1024 +
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(coef1 * hist1 + coef2 * hist2))>>11
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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_16 = hist1;
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stream->adpcm_history2_16 = hist2;
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}
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/*
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* The original DSP spec uses nibble counts for loop points, and some
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* variants don't have a proper sample count, so we (who are interested
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* in sample counts) need to do this conversion occasionally.
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*/
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int32_t dsp_nibbles_to_samples(int32_t nibbles) {
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int32_t whole_frames = nibbles/16;
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int32_t remainder = nibbles%16;
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/*
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fprintf(stderr,"%d (%#x) nibbles => %x bytes and %d samples\n",nibbles,nibbles,whole_frames*8,remainder);
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*/
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#if 0
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if (remainder > 0 && remainder < 14)
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return whole_frames*14 + remainder;
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else if (remainder >= 14)
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fprintf(stderr,"***** last frame %d leftover nibbles makes no sense\n",remainder);
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#endif
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if (remainder>0) return whole_frames*14+remainder-2;
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else return whole_frames*14;
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}
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