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Tweak AWE32 impl to support Uplift.mid
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@derselbst
derselbst committed Oct 6, 2024
1 parent e35b0a4 commit 6f1778f
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Showing 2 changed files with 30 additions and 32 deletions.
4 changes: 3 additions & 1 deletion src/synth/fluid_chan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -131,7 +131,9 @@ fluid_channel_init_ctrl(fluid_channel_t *chan, int is_all_ctrl_off)
chan->override_gen_default[i].flags = GEN_UNUSED;
chan->override_gen_default[i].val = 0.0f;
}
chan->awe32_filter_coeff = -1;
// Not all MIDIs initialize the IIR filter coefficient, e.g. Uplift.mid.
// A default value is not documented, hence I'm assuming zero here.
chan->awe32_filter_coeff = 0;

if(is_all_ctrl_off)
{
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58 changes: 27 additions & 31 deletions src/synth/fluid_synth.c
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Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,7 @@ static void fluid_synth_stop_LOCAL(fluid_synth_t *synth, unsigned int id);

static int fluid_synth_set_important_channels(fluid_synth_t *synth, const char *channels);

static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan, int gen, int data);
static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan, int gen, int data, int data_lsb);

/* Callback handlers for real-time settings */
static void fluid_synth_handle_gain(void *data, const char *name, double value);
Expand Down Expand Up @@ -1847,11 +1847,11 @@ fluid_synth_cc_LOCAL(fluid_synth_t *synth, int channum, int num)
int gen = fluid_channel_get_cc(chan, NRPN_LSB);
if(synth->verbose)
{
FLUID_LOG(FLUID_INFO, "AWE32 NRPN\t%d\t%d\t%d", channum, gen, data);
FLUID_LOG(FLUID_INFO, "AWE32 NRPN RAW: Chan %d, Gen %d, data %d | 0x%X, MSB: %d, LSB: %d", channum, gen, data, data, msb_value, lsb_value);
}
if(gen <= 26) // Effect 26 (reverb) is the last effect to select
{
fluid_synth_process_awe32_nrpn_LOCAL(synth, channum, gen, data);
fluid_synth_process_awe32_nrpn_LOCAL(synth, channum, gen, data, lsb_value);
}
else
{
Expand Down Expand Up @@ -7673,7 +7673,7 @@ calc_awe32_filter_q(int data, fluid_real_t* fc)
* @param gen the AWE32 effect or generator to manipulate
* @param data the composed value of DATA_MSB and DATA_LSB
*/
static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan, int gen, int data)
static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan, int gen, int data, int data_lsb)
{
static const enum fluid_gen_type awe32_to_sf2_gen[] =
{
Expand Down Expand Up @@ -7711,9 +7711,11 @@ static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan,
enum fluid_gen_type sf2_gen = awe32_to_sf2_gen[gen];
int is_realtime = FALSE, i, coef;
fluid_real_t converted_sf2_generator_value, q;


// The AWE32 NRPN docs say that a value of 8192 is considered to be the middle, i.e. zero.
// However, it looks like for those generators which work in range [0,127], the AWE32 only inspects the DATA_LSB, i.e. and not doing this subtraction. Found while investigating Uplift.mid.
data -= 8192;

switch(sf2_gen)
{
case GEN_MODLFODELAY:
Expand All @@ -7726,8 +7728,8 @@ static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan,

case GEN_MODLFOFREQ:
case GEN_VIBLFOFREQ:
fluid_clip(data, 0, 127);
converted_sf2_generator_value = fluid_hz2ct(data * (fluid_real_t)0.084 /* Hz */);
fluid_clip(data_lsb, 0, 127);
converted_sf2_generator_value = fluid_hz2ct(data_lsb * (fluid_real_t)0.084 /* Hz */);
is_realtime = TRUE;
break;

Expand All @@ -7753,8 +7755,8 @@ static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan,

case GEN_MODENVSUSTAIN:
case GEN_VOLENVSUSTAIN:
fluid_clip(data, 0, 127);
converted_sf2_generator_value = data * (fluid_real_t)(0.75 /* dB */ * 10) /* cB */;
fluid_clip(data_lsb, 0, 127);
converted_sf2_generator_value = data_lsb * (fluid_real_t)(0.75 /* dB */ * 10) /* cB */;
break;

case GEN_PITCH:
Expand All @@ -7775,22 +7777,24 @@ static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan,
break;

case GEN_MODLFOTOVOL:
fluid_clip(data, 0, 127);
converted_sf2_generator_value = data * (fluid_real_t)(0.1875 /* dB */ * 10.0) /* cB */;
fluid_clip(data_lsb, 0, 127);
converted_sf2_generator_value = data_lsb * (fluid_real_t)(0.1875 /* dB */ * 10.0) /* cB */;
is_realtime = TRUE;
break;

case GEN_FILTERFC:
fluid_clip(data, 0, 127);
fluid_clip(data_lsb, 0, 127);
// Yes, DO NOT use data here, Uplift.mid doesn't set MSB=64, therefore we would always get a negative value after subtracting 8192.
// Since Uplift.mid sounds fine on hardware though, it seems like AWE32 only inspects DATA_LSB in this case.
// conversion continues below!
converted_sf2_generator_value = (data * 62 /* Hz */);
converted_sf2_generator_value = (data_lsb * 62 /* Hz */);
FLUID_LOG(FLUID_DBG, "AWE32 IIR Fc: %f Hz",converted_sf2_generator_value);
is_realtime = TRUE;
break;

case GEN_FILTERQ:
FLUID_LOG(FLUID_DBG, "AWE32 IIR Q Tab: %d",data);
synth->channel[chan]->awe32_filter_coeff = data;
FLUID_LOG(FLUID_DBG, "AWE32 IIR Q Tab: %d",data_lsb);
synth->channel[chan]->awe32_filter_coeff = data_lsb;
return;

case GEN_MODLFOTOFILTERFC:
Expand Down Expand Up @@ -7835,21 +7839,14 @@ static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan,
{
// The cutoff at fc seems to be very steep for SoundBlaster! hardware. Listening tests have shown that lowering the cutoff frequency by 500Hz gives a closer signal to the SB! hardware filter...
converted_sf2_generator_value -= 500;
if(coef != -1)
{
q = calc_awe32_filter_q(coef, &converted_sf2_generator_value);
FLUID_LOG(FLUID_DBG, "AWE32 IIR Fc (corrected): %f Hz", converted_sf2_generator_value);
FLUID_LOG(FLUID_DBG, "AWE32 IIR Q: %f cB", q);
q = calc_awe32_filter_q(coef, &converted_sf2_generator_value);
FLUID_LOG(FLUID_DBG, "AWE32 IIR Fc (corrected): %f Hz", converted_sf2_generator_value);
FLUID_LOG(FLUID_DBG, "AWE32 IIR Q: %f cB", q);

converted_sf2_generator_value = fluid_hz2ct(converted_sf2_generator_value /* Hz */);
converted_sf2_generator_value = fluid_hz2ct(converted_sf2_generator_value /* Hz */);

// Safe the "true initial Q"
fluid_channel_set_override_gen_default(synth->channel[chan], GEN_FILTERQ, q);
}
else
{
converted_sf2_generator_value = fluid_hz2ct(converted_sf2_generator_value /* Hz */);
}
// Safe the "true initial Q"
fluid_channel_set_override_gen_default(synth->channel[chan], GEN_FILTERQ, q);
}

fluid_channel_set_override_gen_default(synth->channel[chan], sf2_gen, converted_sf2_generator_value);
Expand All @@ -7860,8 +7857,7 @@ static void fluid_synth_process_awe32_nrpn_LOCAL(fluid_synth_t *synth, int chan,

if (fluid_voice_is_playing(voice) && fluid_voice_get_channel(voice) == chan)
{
int coef = synth->channel[chan]->awe32_filter_coeff;
if(sf2_gen == GEN_FILTERFC && coef != -1)
if(sf2_gen == GEN_FILTERFC)
{
// sets the adjusted fc
fluid_voice_gen_set(voice, sf2_gen, converted_sf2_generator_value);
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