Doc addition and better mix

Author: gamblor21

shared-bindings/audiodelays/Reverb.c

@@ -17,44 +17,35 @@
 #include "shared-bindings/util.h"
 #include "shared-module/synthio/block.h"
 
-#define DECAY_DEFAULT 0.7f
-#define MIX_DEFAULT 0.5f
-
 //| class Reverb:
 //|     """An Reverb effect"""
 //|
 //|     def __init__(
 //|         self,
-//|         max_delay_ms: int = 500,
-//|         delay_ms: synthio.BlockInput = 250.0,
-//|         decay: synthio.BlockInput = 0.7,
+//|         roomsize: synthio.BlockInput = 0.5,
+//|         damp: synthio.BlockInput = 0.5,
 //|         mix: synthio.BlockInput = 0.5,
 //|         buffer_size: int = 512,
 //|         sample_rate: int = 8000,
 //|         bits_per_sample: int = 16,
 //|         samples_signed: bool = True,
 //|         channel_count: int = 1,
 //|     ) -> None:
-//|         """Create a Reverb effect where you hear the original sample play back, at a lesser volume after
-//|            a set number of millisecond delay. The delay timing of the reverb can be changed at runtime
-//|            with the delay_ms parameter but the delay can never exceed the max_delay_ms parameter. The
-//|            maximum delay you can set is limited by available memory.
-//|
-//|            Each time the reverb plays back the volume is reduced by the decay setting (reverb * decay).
+//|         """Create a Reverb effect simulating the audio taking place in a large room where you get echos
+//|            off of various surfaces at various times. The size of the room can be adjusted as well as how
+//|            much the higher frequencies get absorbed by the walls.
 //|
 //|            The mix parameter allows you to change how much of the unchanged sample passes through to
 //|            the output to how much of the effect audio you hear as the output.
 //|
-//|         :param int max_delay_ms: The maximum time the reverb can be in milliseconds
-//|         :param synthio.BlockInput delay_ms: The current time of the reverb delay in milliseconds. Must be less the max_delay_ms
-//|         :param synthio.BlockInput decay: The rate the reverb fades. 0.0 = instant; 1.0 = never.
+//|         :param synthio.BlockInput roomsize: The size of the room. 0.0 = smallest; 1.0 = largest.
+//|         :param synthio.BlockInput damp: How much the walls absorb. 0.0 = least; 1.0 = most.
 //|         :param synthio.BlockInput mix: The mix as a ratio of the sample (0.0) to the effect (1.0).
 //|         :param int buffer_size: The total size in bytes of each of the two playback buffers to use
 //|         :param int sample_rate: The sample rate to be used
 //|         :param int channel_count: The number of channels the source samples contain. 1 = mono; 2 = stereo.
-//|         :param int bits_per_sample: The bits per sample of the effect
-//|         :param bool samples_signed: Effect is signed (True) or unsigned (False)
-//|         :param bool freq_shift: Do reverbs change frequency as the reverb delay changes
+//|         :param int bits_per_sample: The bits per sample of the effect. Reverb requires 16 bits.
+//|         :param bool samples_signed: Effect is signed (True) or unsigned (False). Reverb requires signed (True).
 //|
 //|         Playing adding an reverb to a synth::
 //|
@@ -66,14 +57,14 @@
 //|
 //|           audio = audiobusio.I2SOut(bit_clock=board.GP20, word_select=board.GP21, data=board.GP22)
 //|           synth = synthio.Synthesizer(channel_count=1, sample_rate=44100)
-//|           reverb = audiodelays.Reverb(max_delay_ms=1000, delay_ms=850, decay=0.65, buffer_size=1024, channel_count=1, sample_rate=44100, mix=0.7, freq_shift=False)
+//|           reverb = audiodelays.Reverb(roomsize=0.7, damp=0.3, buffer_size=1024, channel_count=1, sample_rate=44100, mix=0.7)
 //|           reverb.play(synth)
 //|           audio.play(reverb)
 //|
 //|           note = synthio.Note(261)
 //|           while True:
 //|               synth.press(note)
-//|               time.sleep(0.25)
+//|               time.sleep(0.55)
 //|               synth.release(note)
 //|               time.sleep(5)"""
 //|         ...
@@ -139,7 +130,7 @@ static void check_for_deinit(audiodelays_reverb_obj_t *self) {
 //  Provided by context manager helper.
 
 //|     roomsize: synthio.BlockInput
-//|     """TODO. Apparent roomsize 0.0-1.0"""
+//|     """Apparent size of the room 0.0-1.0"""
 static mp_obj_t audiodelays_reverb_obj_get_roomsize(mp_obj_t self_in) {
     return common_hal_audiodelays_reverb_get_roomsize(self_in);
 }
@@ -157,7 +148,7 @@ MP_PROPERTY_GETSET(audiodelays_reverb_roomsize_obj,
     (mp_obj_t)&audiodelays_reverb_set_roomsize_obj);
 
 //|     damp: synthio.BlockInput
-//|     """TODO. How reverbrent the area is. 0.0-1.0"""
+//|     """How reverbrent the area is. 0.0-1.0"""
 static mp_obj_t audiodelays_reverb_obj_get_damp(mp_obj_t self_in) {
     return common_hal_audiodelays_reverb_get_damp(self_in);
 }

shared-module/audiodelays/Reverb.c

@@ -173,6 +173,12 @@ void common_hal_audiodelays_reverb_set_mix(audiodelays_reverb_obj_t *self, mp_ob
     synthio_block_assign_slot(mix, &self->mix, MP_QSTR_mix);
 }
 
+void audiodelays_reverb_get_mix_fixedpoint(mp_float_t mix, int16_t *mix_sample, int16_t *mix_effect) {
+    mix = mix * MICROPY_FLOAT_CONST(2.0);
+    *mix_sample = MIN(MICROPY_FLOAT_CONST(2.0) - mix, MICROPY_FLOAT_CONST(1.0)) * 32767;
+    *mix_effect = MIN(mix, MICROPY_FLOAT_CONST(1.0)) * 32767;
+}
+
 void audiodelays_reverb_reset_buffer(audiodelays_reverb_obj_t *self,
     bool single_channel_output,
     uint8_t channel) {
@@ -277,7 +283,10 @@ audioio_get_buffer_result_t audiodelays_reverb_get_buffer(audiodelays_reverb_obj
         mp_float_t damp = synthio_block_slot_get_limited(&self->damp, MICROPY_FLOAT_CONST(0.0), MICROPY_FLOAT_CONST(1.0));
         int16_t damp1, damp2;
         audiodelays_reverb_get_damp_fixedpoint(damp, &damp1, &damp2);
+
         mp_float_t mix = synthio_block_slot_get_limited(&self->mix, MICROPY_FLOAT_CONST(0.0), MICROPY_FLOAT_CONST(1.0));
+        int16_t mix_sample, mix_effect;
+        audiodelays_reverb_get_mix_fixedpoint(mix, &mix_sample, &mix_effect);
 
         mp_float_t roomsize = synthio_block_slot_get_limited(&self->roomsize, MICROPY_FLOAT_CONST(0.0), MICROPY_FLOAT_CONST(1.0));
         int16_t feedback = audiodelays_reverb_get_roomsize_fixedpoint(roomsize);
@@ -320,7 +329,7 @@ audioio_get_buffer_result_t audiodelays_reverb_get_buffer(audiodelays_reverb_obj
 
             word = output * 30;
 
-            word = (sample_word * (MICROPY_FLOAT_CONST(1.0) - mix)) + (word * mix);
+            word = sat16(sample_word * mix_sample, 15) + sat16(word * mix_effect, 15);
             word = synthio_mix_down_sample(word, SYNTHIO_MIX_DOWN_SCALE(2));
             word_buffer[i] = (int16_t)word;
 

shared-module/audiodelays/Reverb.h

@@ -53,3 +53,4 @@ audioio_get_buffer_result_t audiodelays_reverb_get_buffer(audiodelays_reverb_obj
 
 int16_t audiodelays_reverb_get_roomsize_fixedpoint(mp_float_t n);
 void audiodelays_reverb_get_damp_fixedpoint(mp_float_t n, int16_t *damp1, int16_t *damp2);
+void audiodelays_reverb_get_mix_fixedpoint(mp_float_t mix, int16_t *mix_sample, int16_t *mix_effect);