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deanm1278deanm1278
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DM: adding mixer gain
1 parent 7dc6b1d commit 008799d

4 files changed

Lines changed: 120 additions & 0 deletions

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‎shared-bindings/audioio/Mixer.c‎

Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -190,6 +190,39 @@ STATIC mp_obj_t audioio_mixer_obj_stop_voice(size_t n_args, const mp_obj_t *pos_
190190
}
191191
MP_DEFINE_CONST_FUN_OBJ_KW(audioio_mixer_stop_voice_obj, 1, audioio_mixer_obj_stop_voice);
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193+
//| .. method:: set_gain(voice, gain)
194+
//|
195+
//| Set the gain of a voice.
196+
//|
197+
//| gain must be a floating point number between 0 and 1
198+
//|
199+
STATIC mp_obj_t audioio_mixer_obj_set_gain(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
200+
enum { ARG_voice, ARG_gain };
201+
static const mp_arg_t allowed_args[] = {
202+
{ MP_QSTR_voice, MP_ARG_INT | MP_ARG_REQUIRED },
203+
{ MP_QSTR_gain, MP_ARG_OBJ | MP_ARG_REQUIRED },
204+
};
205+
audioio_mixer_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
206+
raise_error_if_deinited(common_hal_audioio_mixer_deinited(self));
207+
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
208+
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
209+
210+
#if MICROPY_PY_BUILTINS_FLOAT
211+
float gain = mp_obj_get_float(args[ARG_gain].u_obj);
212+
#else
213+
#error "floating point not supported"
214+
#endif
215+
216+
if (gain > 1 || gain < 0) {
217+
mp_raise_ValueError(translate("gain must be between 0 and 1"));
218+
}
219+
220+
common_hal_audioio_mixer_set_gain(self,args[ARG_voice].u_int, gain);
221+
222+
return mp_const_none;
223+
}
224+
MP_DEFINE_CONST_FUN_OBJ_KW(audioio_mixer_set_gain_obj, 1, audioio_mixer_obj_set_gain);
225+
193226
//| .. attribute:: playing
194227
//|
195228
//| True when any voice is being output. (read-only)
@@ -234,6 +267,7 @@ STATIC const mp_rom_map_elem_t audioio_mixer_locals_dict_table[] = {
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{ MP_ROM_QSTR(MP_QSTR___exit__), MP_ROM_PTR(&audioio_mixer___exit___obj) },
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{ MP_ROM_QSTR(MP_QSTR_play), MP_ROM_PTR(&audioio_mixer_play_obj) },
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{ MP_ROM_QSTR(MP_QSTR_stop_voice), MP_ROM_PTR(&audioio_mixer_stop_voice_obj) },
270+
{ MP_ROM_QSTR(MP_QSTR_set_gain), MP_ROM_PTR(&audioio_mixer_set_gain_obj) },
237271

238272
// Properties
239273
{ MP_ROM_QSTR(MP_QSTR_playing), MP_ROM_PTR(&audioio_mixer_playing_obj) },

‎shared-bindings/audioio/Mixer.h‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -45,6 +45,7 @@ void common_hal_audioio_mixer_deinit(audioio_mixer_obj_t* self);
4545
bool common_hal_audioio_mixer_deinited(audioio_mixer_obj_t* self);
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void common_hal_audioio_mixer_play(audioio_mixer_obj_t* self, mp_obj_t sample, uint8_t voice, bool loop);
4747
void common_hal_audioio_mixer_stop_voice(audioio_mixer_obj_t* self, uint8_t voice);
48+
void common_hal_audioio_mixer_set_gain(audioio_mixer_obj_t* self, uint8_t voice, float gain);
4849

4950
bool common_hal_audioio_mixer_get_playing(audioio_mixer_obj_t* self);
5051
uint32_t common_hal_audioio_mixer_get_sample_rate(audioio_mixer_obj_t* self);

‎shared-module/audioio/Mixer.c‎

Lines changed: 84 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -61,6 +61,7 @@ void common_hal_audioio_mixer_construct(audioio_mixer_obj_t* self,
6161

6262
for (uint8_t i = 0; i < self->voice_count; i++) {
6363
self->voice[i].sample = NULL;
64+
self->voice[i].gain = ((1<<15)-1);
6465
}
6566
}
6667

@@ -131,6 +132,11 @@ void audioio_mixer_reset_buffer(audioio_mixer_obj_t* self,
131132
}
132133
}
133134

135+
void common_hal_audioio_mixer_set_gain(audioio_mixer_obj_t* self, uint8_t voice, float gain) {
136+
audioio_mixer_voice_t* v = &self->voice[voice];
137+
v->gain = gain * ((1 << 15)-1);
138+
}
139+
134140
uint32_t add8signed(uint32_t a, uint32_t b) {
135141
#if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
136142
return __QADD8(a, b);
@@ -215,6 +221,68 @@ uint32_t add16unsigned(uint32_t a, uint32_t b) {
215221
#endif
216222
}
217223

224+
//TODO:
225+
static inline uint32_t mult8unsigned(uint32_t val, int32_t mul) {
226+
#if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
227+
return val;
228+
val = __USUB8(val, 0x80808080);
229+
#else
230+
uint32_t result = 0;
231+
for (int8_t i = 0; i < 4; i++) {
232+
int8_t ai = (val >> (sizeof(uint8_t) * 8 * i)) - 128;
233+
}
234+
return result;
235+
#endif
236+
}
237+
238+
//TODO:
239+
static inline uint32_t mult8signed(uint32_t val, int32_t mul) {
240+
#if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
241+
return val;
242+
#else
243+
uint32_t result = 0;
244+
for (int8_t i = 0; i < 4; i++) {
245+
int8_t ai = val >> (sizeof(int8_t) * 8 * i);
246+
}
247+
return result;
248+
#endif
249+
}
250+
251+
//TODO:
252+
static inline uint32_t mult16unsigned(uint32_t val, int32_t mul) {
253+
#if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
254+
return val;
255+
val = __USUB16(val, 0x80008000);
256+
#else
257+
uint32_t result = 0;
258+
for (int8_t i = 0; i < 2; i++) {
259+
int16_t ai = (val >> (sizeof(uint16_t) * 8 * i)) - 0x8000;
260+
}
261+
return result;
262+
#endif
263+
}
264+
265+
static inline uint32_t mult16signed(uint32_t val, int32_t mul) {
266+
#if (defined (__ARM_FEATURE_DSP) && (__ARM_FEATURE_DSP == 1))
267+
int32_t hi, lo;
268+
int32_t bits = 16; // saturate to 16 bits
269+
int32_t shift = 0; // shift is done automatically
270+
asm volatile("smulwb %0, %1, %2" : "=r" (lo) : "r" (mul), "r" (val));
271+
asm volatile("smulwt %0, %1, %2" : "=r" (hi) : "r" (mul), "r" (val));
272+
asm volatile("ssat %0, %1, %2, asr %3" : "=r" (lo) : "I" (bits), "r" (lo), "I" (shift));
273+
asm volatile("ssat %0, %1, %2, asr %3" : "=r" (hi) : "I" (bits), "r" (hi), "I" (shift));
274+
asm volatile("pkhbt %0, %1, %2, lsl #16" : "=r" (val) : "r" (lo), "r" (hi)); // pack
275+
return val;
276+
#else
277+
uint32_t result = 0;
278+
//TODO:
279+
for (int8_t i = 0; i < 2; i++) {
280+
int16_t ai = val >> (sizeof(int16_t) * 8 * i);
281+
}
282+
return result;
283+
#endif
284+
}
285+
218286
audioio_get_buffer_result_t audioio_mixer_get_buffer(audioio_mixer_obj_t* self,
219287
bool single_channel,
220288
uint8_t channel,
@@ -285,6 +353,22 @@ audioio_get_buffer_result_t audioio_mixer_get_buffer(audioio_mixer_obj_t* self,
285353
sample_value = voice->remaining_buffer[j];
286354
}
287355

356+
// apply the mixer gain
357+
if (!self->samples_signed) {
358+
if (self->bits_per_sample == 8) {
359+
sample_value = mult8unsigned(sample_value, voice->gain);
360+
} else {
361+
sample_value = mult16unsigned(sample_value, voice->gain);
362+
}
363+
}
364+
else{
365+
if (self->bits_per_sample == 8) {
366+
sample_value = mult8signed(sample_value, voice->gain);
367+
} else {
368+
sample_value = mult16signed(sample_value, voice->gain);
369+
}
370+
}
371+
288372
if (!voices_active) {
289373
word_buffer[i] = sample_value;
290374
} else {

‎shared-module/audioio/Mixer.h‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -37,6 +37,7 @@ typedef struct {
3737
bool more_data;
3838
uint32_t* remaining_buffer;
3939
uint32_t buffer_length;
40+
int16_t gain;
4041
} audioio_mixer_voice_t;
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4243
typedef struct {

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