Merge pull request #9994 from relic-se/audiodelays_mix_fix

Change mix calculation on `audiodelays.Echo` to allow full range.

Author: dhalbert

shared-bindings/audiodelays/Echo.c

@@ -17,9 +17,6 @@
 #include "shared-bindings/util.h"
 #include "shared-module/synthio/block.h"
 
-#define DECAY_DEFAULT 0.7f
-#define MIX_DEFAULT 0.5f
-
 //| class Echo:
 //|     """An Echo effect"""
 //|
@@ -28,7 +25,7 @@
 //|         max_delay_ms: int = 500,
 //|         delay_ms: synthio.BlockInput = 250.0,
 //|         decay: synthio.BlockInput = 0.7,
-//|         mix: synthio.BlockInput = 0.5,
+//|         mix: synthio.BlockInput = 0.25,
 //|         buffer_size: int = 512,
 //|         sample_rate: int = 8000,
 //|         bits_per_sample: int = 16,
@@ -163,7 +160,7 @@ MP_PROPERTY_GETSET(audiodelays_echo_delay_ms_obj,
     (mp_obj_t)&audiodelays_echo_set_delay_ms_obj);
 
 //|     decay: synthio.BlockInput
-//|     """The rate the echo decays between 0 and 1 where 1 is forever and 0 is no echo."""
+//|     """The rate the echo fades between 0 and 1 where 0 is instant and 1 is never."""
 static mp_obj_t audiodelays_echo_obj_get_decay(mp_obj_t self_in) {
     return common_hal_audiodelays_echo_get_decay(self_in);
 }
@@ -181,7 +178,7 @@ MP_PROPERTY_GETSET(audiodelays_echo_decay_obj,
     (mp_obj_t)&audiodelays_echo_set_decay_obj);
 
 //|     mix: synthio.BlockInput
-//|     """The rate the echo mix between 0 and 1 where 0 is only sample and 1 is all effect."""
+//|     """The rate the echo mix between 0 and 1 where 0 is only sample, 0.5 is an equal mix of the sample and the effect and 1 is all effect."""
 static mp_obj_t audiodelays_echo_obj_get_mix(mp_obj_t self_in) {
     return common_hal_audiodelays_echo_get_mix(self_in);
 }

shared-bindings/audiofilters/Filter.c

@@ -17,8 +17,6 @@
 #include "shared-bindings/util.h"
 #include "shared-module/synthio/block.h"
 
-#define MIX_DEFAULT 1.0f
-
 //| class Filter:
 //|     """A Filter effect"""
 //|

shared-module/audiodelays/Echo.c

@@ -71,7 +71,7 @@ void common_hal_audiodelays_echo_construct(audiodelays_echo_obj_t *self, uint32_
     synthio_block_assign_slot(delay_ms, &self->delay_ms, MP_QSTR_delay_ms);
 
     if (mix == MP_OBJ_NULL) {
-        mix = mp_obj_new_float(MICROPY_FLOAT_CONST(0.5));
+        mix = mp_obj_new_float(MICROPY_FLOAT_CONST(0.25));
     }
     synthio_block_assign_slot(mix, &self->mix, MP_QSTR_mix);
 
@@ -268,7 +268,7 @@ audioio_get_buffer_result_t audiodelays_echo_get_buffer(audiodelays_echo_obj_t *
 
         // get the effect values we need from the BlockInput. These may change at run time so you need to do bounds checking if required
         shared_bindings_synthio_lfo_tick(self->base.sample_rate, n / self->base.channel_count);
-        mp_float_t mix = synthio_block_slot_get_limited(&self->mix, MICROPY_FLOAT_CONST(0.0), MICROPY_FLOAT_CONST(1.0));
+        mp_float_t mix = synthio_block_slot_get_limited(&self->mix, MICROPY_FLOAT_CONST(0.0), MICROPY_FLOAT_CONST(1.0)) * MICROPY_FLOAT_CONST(2.0);
         mp_float_t decay = synthio_block_slot_get_limited(&self->decay, MICROPY_FLOAT_CONST(0.0), MICROPY_FLOAT_CONST(1.0));
 
         mp_float_t f_delay_ms = synthio_block_slot_get(&self->delay_ms);
@@ -323,7 +323,7 @@ audioio_get_buffer_result_t audiodelays_echo_get_buffer(audiodelays_echo_obj_t *
                         echo_buffer[self->echo_buffer_write_pos++] = word;
                     }
 
-                    word = (int16_t)(echo * mix);
+                    word = (int16_t)(echo * MIN(mix, MICROPY_FLOAT_CONST(1.0)));
 
                     if (MP_LIKELY(self->base.bits_per_sample == 16)) {
                         word_buffer[i] = word;
@@ -414,16 +414,17 @@ audioio_get_buffer_result_t audiodelays_echo_get_buffer(audiodelays_echo_obj_t *
                         }
                     }
 
-                    word = echo + sample_word;
+                    word = (int32_t)((sample_word * MIN(MICROPY_FLOAT_CONST(2.0) - mix, MICROPY_FLOAT_CONST(1.0)))
+                        + (echo * MIN(mix, MICROPY_FLOAT_CONST(1.0))));
                     word = synthio_mix_down_sample(word, SYNTHIO_MIX_DOWN_SCALE(2));
 
                     if (MP_LIKELY(self->base.bits_per_sample == 16)) {
-                        word_buffer[i] = (int16_t)((sample_word * (MICROPY_FLOAT_CONST(1.0) - mix)) + (word * mix));
+                        word_buffer[i] = (int16_t)word;
                         if (!self->base.samples_signed) {
                             word_buffer[i] ^= 0x8000;
                         }
                     } else {
-                        int8_t mixed = (int16_t)((sample_word * (MICROPY_FLOAT_CONST(1.0) - mix)) + (word * mix));
+                        int8_t mixed = (int16_t)word;
                         if (self->base.samples_signed) {
                             hword_buffer[i] = mixed;
                         } else {