From e372e19057f54297f5a551ec98e3a50d14fac271 Mon Sep 17 00:00:00 2001 From: bnnm Date: Sat, 21 Sep 2019 18:52:57 +0200 Subject: [PATCH] Fix Yamaha AICA decoding being slightly off and cleanup --- src/coding/yamaha_decoder.c | 149 +++++++++++++++++++++++------------- 1 file changed, 97 insertions(+), 52 deletions(-) diff --git a/src/coding/yamaha_decoder.c b/src/coding/yamaha_decoder.c index 2f4261dc..71d9f9d3 100644 --- a/src/coding/yamaha_decoder.c +++ b/src/coding/yamaha_decoder.c @@ -1,30 +1,88 @@ #include "../util.h" #include "coding.h" -/* fixed point (.8) amount to scale the current step size by */ -/* part of the same series as used in MS ADPCM "ADPCMTable" */ -static const unsigned int scale_step[16] = { +/* fixed point amount to scale the current step size */ +static const unsigned int scale_step_aica[16] = { 230, 230, 230, 230, 307, 409, 512, 614, 230, 230, 230, 230, 307, 409, 512, 614 }; -/* actually implemented with if-else/switchs but that's too goofy */ -static const int scale_step_aska[8] = { +static const int scale_step_adpcmb[16] = { + 57, 57, 57, 57, 77, 102, 128, 153, 57, 57, 57, 57, 77, 102, 128, 153, }; -/* expand an unsigned four bit delta to a wider signed range */ +/* look-up for 'mul' IMA's sign*((code&7) * 2 + 1) for every code */ static const int scale_delta[16] = { 1, 3, 5, 7, 9, 11, 13, 15, -1, -3, -5, -7, -9,-11,-13,-15 }; +/* Yamaha ADPCM-B (aka DELTA-T) expand used in YM2608/YM2610/etc (cross referenced with various sources and .so) */ +static void yamaha_adpcmb_expand_nibble(VGMSTREAMCHANNEL * stream, off_t byte_offset, int nibble_shift, int32_t* hist1, int32_t* step_size, int16_t *out_sample) { + int code, delta, sample; -/* raw Yamaha ADPCM a.k.a AICA as it's prominently used in Naomi/Dreamcast's Yamaha AICA sound chip, - * also found in Windows RIFF and older Yamaha's arcade sound chips. */ + code = (read_8bit(byte_offset,stream->streamfile) >> nibble_shift) & 0xf; + delta = ((((code & 0x7) * 2) + 1) * (*step_size)) >> 3; /* like 'mul' IMA */ + if (code & 8) + delta = -delta; + sample = *hist1 + delta; + + sample = clamp16(sample); /* this may not be needed (not done in Aska) but no byte changes */ + + *step_size = ((*step_size) * scale_step_adpcmb[code]) >> 6; + if (*step_size < 0x7f) *step_size = 0x7f; + else if (*step_size > 0x6000) *step_size = 0x6000; + + *out_sample = sample; + *hist1 = sample; +} + +/* Yamaha AICA expand, slightly filtered vs "ACM" Yamaha ADPCM, same as Creative ADPCM + * (some info from https://github.com/vgmrips/vgmplay, https://wiki.multimedia.cx/index.php/Creative_ADPCM) */ +static void yamaha_aica_expand_nibble(VGMSTREAMCHANNEL * stream, off_t byte_offset, int nibble_shift, int32_t* hist1, int32_t* step_size, int16_t *out_sample) { + int code, delta, sample; + + *hist1 = *hist1 * 254 / 256; /* hist filter is vital to get correct waveform but not done in many emus */ + + code = ((read_8bit(byte_offset,stream->streamfile) >> nibble_shift))&0xf; + delta = (*step_size * scale_delta[code]) / 8; /* 'mul' IMA with table (not sure if part of encoder) */ + sample = *hist1 + delta; + + sample = clamp16(sample); /* apparently done by official encoder */ + + *step_size = ((*step_size) * scale_step_aica[code]) >> 8; + if (*step_size < 0x7f) *step_size = 0x7f; + else if (*step_size > 0x6000) *step_size = 0x6000; + + *out_sample = sample; + *hist1 = sample; +} + + +/* info about Yamaha ADPCM as created by official yadpcm.acm (in 'Yamaha-ADPCM-ACM-Driver-100-j') + * - possibly RIFF codec 0x20 + * - simply called "Yamaha ADPCM Codec" (even though not quite like Yamaha ADPCM-B) + * - block_align = (sample_rate / 0x3C + 0x04) * channels (ex. 0x2E6 for 22050 stereo, probably given in RIFF) + * - low nibble first, stereo or mono modes (no interleave) + * - expand (old IMA 'shift+add' style, not 'mul' style): + * delta = step_size >> 3; + * if (code & 1) delta += step_size >> 2; + * if (code & 2) delta += step_size >> 1; + * if (code & 4) delta += step_size; + * if (code & 8) delta = -delta; + * sample = hist + clamp16(delta); + * though compiled more like: + * sample = hist + (1-2*(code & 8) * (step_size/8 + step_size/2 * (code&2) + step_size/4 * (code&1) + step_size * (code&4)) + * - step_size update: + * step_size = clamp_range(step_size * scale_step_aica[code] >> 8, 0x7F, 0x6000) + */ + + +/* Yamaha AICA ADPCM (also used in YMZ280B with high nibble first) */ void decode_yamaha(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int channel, int is_stereo) { - int i, sample_count; - + int i, sample_count = 0; + int16_t out_sample; int32_t hist1 = stream->adpcm_history1_16; int step_size = stream->adpcm_step_index; @@ -32,8 +90,7 @@ void decode_yamaha(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspac if (step_size < 0x7f) step_size = 0x7f; if (step_size > 0x6000) step_size = 0x6000; - for (i=first_sample,sample_count=0; ioffset + i : /* stereo: one nibble per channel */ stream->offset + i/2; /* mono: consecutive nibbles */ @@ -41,26 +98,20 @@ void decode_yamaha(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspac (!(channel&1) ? 0:4) : /* even = low/L, odd = high/R */ (!(i&1) ? 0:4); /* low nibble first */ - /* Yamaha/AICA expand, but same result as IMA's (((delta * 2 + 1) * step) >> 3) */ - sample_nibble = ((read_8bit(byte_offset,stream->streamfile) >> nibble_shift))&0xf; - sample_delta = (step_size * scale_delta[sample_nibble]) / 8; - sample_decoded = hist1 + sample_delta; - - outbuf[sample_count] = clamp16(sample_decoded); - hist1 = outbuf[sample_count]; - - step_size = (step_size * scale_step[sample_nibble]) >> 8; - if (step_size < 0x7f) step_size = 0x7f; - if (step_size > 0x6000) step_size = 0x6000; + yamaha_aica_expand_nibble(stream, byte_offset, nibble_shift, &hist1, &step_size, &out_sample); + outbuf[sample_count] = out_sample; + sample_count += channelspacing; } stream->adpcm_history1_16 = hist1; stream->adpcm_step_index = step_size; } -/* tri-Ace Aska ADPCM, same-ish with modified step table (reversed from Android SO's .so) */ +/* tri-Ace Aska ADPCM, Yamaha ADPCM-B with headered frames (reversed from Android SO's .so) + * implements table with if-else/switchs too but that's too goofy */ void decode_aska(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int channel) { - int i, sample_count, num_frame; + int i, sample_count = 0, num_frame; + int16_t out_sample; int32_t hist1 = stream->adpcm_history1_32; int step_size = stream->adpcm_step_index; @@ -75,13 +126,13 @@ void decode_aska(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacin hist1 = read_16bitLE(header_offset+0x00,stream->streamfile); step_size = read_16bitLE(header_offset+0x02,stream->streamfile); - if (step_size < 0x7f) step_size = 0x7f; - if (step_size > 0x6000) step_size = 0x6000; + /* in most files 1st frame has step 0 but it seems ok and accounted for */ + //if (step_size < 0x7f) step_size = 0x7f; + //else if (step_size > 0x6000) step_size = 0x6000; } /* decode nibbles (layout: varies) */ - for (i=first_sample,sample_count=0; ioffset + 0x40*num_frame + 0x04*channelspacing) + i : /* stereo: one nibble per channel */ (stream->offset + 0x40*num_frame + 0x04*channelspacing) + i/2; /* mono: consecutive nibbles */ @@ -89,26 +140,19 @@ void decode_aska(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacin (!(channel&1) ? 0:4) : (!(i&1) ? 0:4); /* even = low, odd = high */ - sample_nibble = (read_8bit(byte_offset,stream->streamfile) >> nibble_shift) & 0xf; - sample_delta = ((((sample_nibble & 0x7) * 2) | 1) * step_size) >> 3; /* like 'mul' IMA with 'or' */ - if (sample_nibble & 8) sample_delta = -sample_delta; - sample_decoded = hist1 + sample_delta; - - outbuf[sample_count] = sample_decoded; /* not clamped */ - hist1 = outbuf[sample_count]; - - step_size = (step_size * scale_step_aska[sample_nibble & 0x07]) >> 6; - if (step_size < 0x7f) step_size = 0x7f; - if (step_size > 0x6000) step_size = 0x6000; + yamaha_adpcmb_expand_nibble(stream, byte_offset, nibble_shift, &hist1, &step_size, &out_sample); + outbuf[sample_count] = out_sample; + sample_count += channelspacing; } stream->adpcm_history1_32 = hist1; stream->adpcm_step_index = step_size; } + /* Yamaha ADPCM with unknown expand variation (noisy), step size is double of normal Yamaha? */ void decode_nxap(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) { - int i, sample_count, num_frame; + int i, sample_count = 0, num_frame; int32_t hist1 = stream->adpcm_history1_32; int step_size = stream->adpcm_step_index; @@ -124,26 +168,27 @@ void decode_nxap(VGMSTREAMCHANNEL * stream, sample_t * outbuf, int channelspacin hist1 = read_16bitLE(header_offset+0x00,stream->streamfile); step_size = read_16bitLE(header_offset+0x02,stream->streamfile); if (step_size < 0x7f) step_size = 0x7f; - if (step_size > 0x6000) step_size = 0x6000; + else if (step_size > 0x6000) step_size = 0x6000; } /* decode nibbles (layout: all nibbles from one channel) */ - for (i=first_sample,sample_count=0; ioffset + 0x40*num_frame + 0x04) + i/2; - int nibble_shift = (i&1?4:0); /* low nibble first */ + int nibble_shift = (i&1?4:0); /* low nibble first? */ - /* Yamaha expand? */ - sample_nibble = (read_8bit(byte_offset,stream->streamfile) >> nibble_shift)&0xf; - sample_delta = (step_size * scale_delta[sample_nibble] / 4) / 8; //todo not ok - sample_decoded = hist1 + sample_delta; + code = (read_8bit(byte_offset,stream->streamfile) >> nibble_shift)&0xf; + delta = (step_size * scale_delta[code]) / 8; //todo wrong + sample = hist1 + delta; - outbuf[sample_count] = clamp16(sample_decoded); + outbuf[sample_count] = clamp16(sample); hist1 = outbuf[sample_count]; - step_size = (step_size * scale_step[sample_nibble]) >> 8; + step_size = (step_size * scale_step_aica[code]) / 260.0; //todo wrong if (step_size < 0x7f) step_size = 0x7f; - if (step_size > 0x6000) step_size = 0x6000; + else if (step_size > 0x6000) step_size = 0x6000; + + sample_count += channelspacing; } stream->adpcm_history1_32 = hist1;