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https://github.com/RaySollium99/picodrive.git
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sound, prepare FM filtering
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kub
parent
882f697ad4
commit
e2e2b6ad1b
8 changed files with 1180 additions and 3 deletions
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@ -14,6 +14,12 @@
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#include "mix.h"
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#include "emu2413/emu2413.h"
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#ifdef USE_BLIPPER
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#include "blipper.h"
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#else
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#include "resampler.h"
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#endif
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void (*PsndMix_32_to_16l)(s16 *dest, s32 *src, int count) = mix_32_to_16l_stereo;
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// master int buffer to mix to
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@ -32,6 +38,11 @@ OPLL old_opll;
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static OPLL *opll = NULL;
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unsigned YM2413_reg;
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#ifdef USE_BLIPPER
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static blipper_t *fmlblip, *fmrblip;
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#else
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static resampler_t *fmresampler;
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#endif
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PICO_INTERNAL void PsndInit(void)
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{
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@ -44,6 +55,13 @@ PICO_INTERNAL void PsndExit(void)
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{
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OPLL_delete(opll);
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opll = NULL;
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#ifdef USE_BLIPPER
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blipper_free(fmlblip); fmlblip = NULL;
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blipper_free(fmrblip); fmrblip = NULL;
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#else
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resampler_free(fmresampler); fmresampler = NULL;
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#endif
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}
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PICO_INTERNAL void PsndReset(void)
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@ -53,6 +71,111 @@ PICO_INTERNAL void PsndReset(void)
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timers_reset();
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}
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int (*PsndFMUpdate)(s32 *buffer, int length, int stereo, int is_buf_empty);
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// FM polyphase FIR resampling
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#ifdef USE_BLIPPER
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#define FMFIR_TAPS 11
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// resample FM from its native 53267Hz/52781Hz with the blipper library
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static u32 ymmulinv;
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int YM2612UpdateFIR(s32 *buffer, int length, int stereo, int is_buf_empty)
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{
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int mul = Pico.snd.fm_fir_mul, div = Pico.snd.fm_fir_div;
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s32 *p = buffer, *q = buffer;
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int ymlen;
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int ret = 0;
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if (length <= 0) return ret;
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// FM samples needed: (length*div + div-blipper_read_phase(fmlblip)) / mul
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ymlen = ((length*div + div-blipper_read_phase(fmlblip)) * ymmulinv) >> 32;
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if (ymlen > 0)
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ret = YM2612UpdateOne(p, ymlen, stereo, is_buf_empty);
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if (stereo) {
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blipper_push_long_samples(fmlblip, p , ymlen, 2, mul);
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blipper_push_long_samples(fmrblip, p+1, ymlen, 2, mul);
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blipper_read_long(fmlblip, q , blipper_read_avail(fmlblip), 2);
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blipper_read_long(fmrblip, q+1, blipper_read_avail(fmrblip), 2);
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} else {
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blipper_push_long_samples(fmlblip, p , ymlen, 1, mul);
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blipper_read_long(fmlblip, q , blipper_read_avail(fmlblip), 1);
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}
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return ret;
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}
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static void YM2612_setup_FIR(int inrate, int outrate, int stereo)
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{
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int mindiff = 999;
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int diff, mul, div;
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int maxdecim = 1500/FMFIR_TAPS;
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// compute filter ratio with smallest error for a decent number of taps
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for (div = maxdecim/2; div <= maxdecim; div++) {
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mul = (outrate*div + inrate/2) / inrate;
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diff = outrate*div/mul - inrate;
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if (abs(diff) < abs(mindiff)) {
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mindiff = diff;
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Pico.snd.fm_fir_mul = mul;
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Pico.snd.fm_fir_div = div;
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}
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}
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ymmulinv = 0x100000000ULL / mul; /* 1/mul in Q32 */
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printf("FM polyphase FIR ratio=%d/%d error=%.3f%%\n",
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Pico.snd.fm_fir_mul, Pico.snd.fm_fir_div, 100.0*mindiff/inrate);
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// create blipper (modified for polyphase resampling). Not really perfect for
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// FM, but has SINC generator, a good window, and computes the filter in Q16.
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blipper_free(fmlblip);
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blipper_free(fmrblip);
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fmlblip = blipper_new(FMFIR_TAPS, 0.85, 8.5, Pico.snd.fm_fir_div, 1000, NULL);
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if (!stereo) return;
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fmrblip = blipper_new(FMFIR_TAPS, 0.85, 8.5, Pico.snd.fm_fir_div, 1000, NULL);
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}
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#else
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#define FMFIR_TAPS 8
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// resample FM from its native 53267Hz/52781Hz with polyphase FIR filter
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static int ymchans;
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static void YM2612Update(s32 *buffer, int length, int stereo)
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{
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ymchans = YM2612UpdateOne(buffer, length, stereo, 1);
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}
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int YM2612UpdateFIR(s32 *buffer, int length, int stereo, int is_buf_empty)
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{
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resampler_update(fmresampler, buffer, length, YM2612Update);
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return ymchans;
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}
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static void YM2612_setup_FIR(int inrate, int outrate, int stereo)
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{
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int mindiff = 999;
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int diff, mul, div;
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int maxmult = 30; // max interpolation factor
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// compute filter ratio with largest multiplier for smallest error
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for (mul = maxmult/2; mul <= maxmult; mul++) {
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div = (inrate*mul + outrate/2) / outrate;
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diff = outrate*div/mul - inrate;
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if (abs(diff) <= abs(mindiff)) {
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mindiff = diff;
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Pico.snd.fm_fir_mul = mul;
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Pico.snd.fm_fir_div = div;
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}
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}
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printf("FM polyphase FIR ratio=%d/%d error=%.3f%%\n",
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Pico.snd.fm_fir_mul, Pico.snd.fm_fir_div, 100.0*mindiff/inrate);
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resampler_free(fmresampler);
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fmresampler = resampler_new(FMFIR_TAPS, Pico.snd.fm_fir_mul, Pico.snd.fm_fir_div,
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0.85, 2.35, 2*inrate/50, stereo);
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}
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#endif
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// to be called after changing sound rate or chips
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void PsndRerate(int preserve_state)
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@ -60,6 +183,7 @@ void PsndRerate(int preserve_state)
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void *state = NULL;
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int target_fps = Pico.m.pal ? 50 : 60;
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int target_lines = Pico.m.pal ? 313 : 262;
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int ym2612_clock = Pico.m.pal ? OSC_PAL/7 : OSC_NTSC/7;
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if (preserve_state) {
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state = malloc(0x204);
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@ -67,9 +191,19 @@ void PsndRerate(int preserve_state)
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ym2612_pack_state();
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memcpy(state, YM2612GetRegs(), 0x204);
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}
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YM2612Init(Pico.m.pal ? OSC_PAL/7 : OSC_NTSC/7, PicoIn.sndRate,
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if (PicoIn.opt & POPT_EN_FM_FILTER) {
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int ym2612_rate = (ym2612_clock+(6*24)/2) / (6*24);
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YM2612Init(ym2612_clock, ym2612_rate,
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((PicoIn.opt&POPT_DIS_FM_SSGEG) ? 0 : ST_SSG) |
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((PicoIn.opt&POPT_EN_FM_DAC) ? ST_DAC : 0));
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YM2612_setup_FIR(ym2612_rate, PicoIn.sndRate, PicoIn.opt & POPT_EN_STEREO);
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PsndFMUpdate = YM2612UpdateFIR;
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} else {
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YM2612Init(ym2612_clock, PicoIn.sndRate,
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((PicoIn.opt&POPT_DIS_FM_SSGEG) ? 0 : ST_SSG) |
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((PicoIn.opt&POPT_EN_FM_DAC) ? ST_DAC : 0));
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PsndFMUpdate = YM2612UpdateOne;
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}
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if (preserve_state) {
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// feed it back it's own registers, just like after loading state
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memcpy(YM2612GetRegs(), state, 0x204);
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@ -267,7 +401,7 @@ PICO_INTERNAL void PsndDoFM(int cyc_to)
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pos <<= 1;
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}
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if (PicoIn.opt & POPT_EN_FM)
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YM2612UpdateOne(PsndBuffer + pos, len, stereo, 1);
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PsndFMUpdate(PsndBuffer + pos, len, stereo, 1);
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}
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// cdda
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@ -383,7 +517,7 @@ static int PsndRender(int offset, int length)
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s32 *fmbuf = buf32 + ((fmlen-offset) << stereo);
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Pico.snd.fm_pos += (length-fmlen) << 20;
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if (PicoIn.opt & POPT_EN_FM)
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YM2612UpdateOne(fmbuf, length-fmlen, stereo, 1);
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PsndFMUpdate(fmbuf, length-fmlen, stereo, 1);
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}
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// CD: PCM sound
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