95 lines
3.5 KiB
C
95 lines
3.5 KiB
C
#include "coding.h"
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#include "../util.h"
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void decode_adx(VGMSTREAMCHANNEL* stream, sample_t* outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int32_t frame_size, coding_t coding_type) {
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uint8_t frame[0x12] = {0};
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off_t frame_offset;
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int i, frames_in, sample_count = 0;
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size_t bytes_per_frame, samples_per_frame;
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int scale, coef1, coef2;
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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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/* external interleave (fixed size), mono */
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bytes_per_frame = frame_size;
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samples_per_frame = (bytes_per_frame - 0x02) * 2; /* always 32 */
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frames_in = first_sample / samples_per_frame;
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first_sample = first_sample % samples_per_frame;
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/* parse frame header */
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frame_offset = stream->offset + bytes_per_frame * frames_in;
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read_streamfile(frame, frame_offset, bytes_per_frame, stream->streamfile); /* ignore EOF errors */
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scale = get_s16be(frame+0x00);
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switch(coding_type) {
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case coding_CRI_ADX:
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scale = scale + 1;
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coef1 = stream->adpcm_coef[0];
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coef2 = stream->adpcm_coef[1];
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/* Detect EOF scale (0x8001) found in some ADX of any type, signals "stop decoding" (without this frame?).
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* Normally num_samples stops right before it, but ADXPLAY will honor it even in the middle on a file
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* (may repeat last sample buffer). Some Baroque (SAT) videos set it on file end, but num_samples goes beyond.
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* Just the upper bit triggers it even in encrypted ADX (max is 0x7FFF), but the check only here just in case. */
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if (frame[0] == 0x80 && frame[1] == 0x01) {
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scale = 0; /* fix scaled click, maybe should just exit */
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VGM_LOG("ADX: reached EOF scale\n");
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}
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break;
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case coding_CRI_ADX_exp:
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scale = 1 << (12 - scale);
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coef1 = stream->adpcm_coef[0];
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coef2 = stream->adpcm_coef[1];
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break;
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case coding_CRI_ADX_fixed:
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scale = (scale & 0x1fff) + 1;
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coef1 = stream->adpcm_coef[(frame[0] >> 5)*2 + 0];
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coef2 = stream->adpcm_coef[(frame[0] >> 5)*2 + 1];
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break;
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case coding_CRI_ADX_enc_8:
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case coding_CRI_ADX_enc_9:
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scale = ((scale ^ stream->adx_xor) & 0x1fff) + 1;
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coef1 = stream->adpcm_coef[0];
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coef2 = stream->adpcm_coef[1];
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break;
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default:
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scale = scale + 1;
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coef1 = stream->adpcm_coef[0];
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coef2 = stream->adpcm_coef[1];
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break;
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}
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/* decode nibbles */
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for (i = first_sample; i < first_sample + samples_to_do; i++) {
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int32_t sample = 0;
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uint8_t nibbles = frame[0x02 + i/2];
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sample = i&1 ? /* high nibble first */
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get_low_nibble_signed(nibbles):
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get_high_nibble_signed(nibbles);
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sample = sample * scale + (coef1 * hist1 >> 12) + (coef2 * hist2 >> 12);
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sample = clamp16(sample);
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outbuf[sample_count] = sample;
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sample_count += channelspacing;
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hist2 = hist1;
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hist1 = sample;
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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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if ((coding_type == coding_CRI_ADX_enc_8 || coding_type == coding_CRI_ADX_enc_9) && !(i % 32)) {
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for (i =0; i < stream->adx_channels; i++) {
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adx_next_key(stream);
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}
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}
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}
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void adx_next_key(VGMSTREAMCHANNEL* stream) {
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stream->adx_xor = (stream->adx_xor * stream->adx_mult + stream->adx_add) & 0x7fff;
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}
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