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MonoWavefile with speed adjustment #1

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179d284
Add MonoWaveFile with adjustable playback speed
Aug 25, 2024
0608823
Rename stretch_factor to speed
Aug 25, 2024
bbab5cf
WIP: 16bit support. Some issues
Aug 28, 2024
d8f3e9e
Fix sample reading
Aug 29, 2024
67e2a45
WIP: configurable buffer size
Sep 30, 2024
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Rename stretch_factor to speed
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Sundström Valter committed Aug 25, 2024
commit 060882346edf4409d9f8d102b64d373ca98a817c
14 changes: 7 additions & 7 deletions shared-module/audiocore/MonoWaveFile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,9 +16,9 @@
#include "shared-module/audiocore/MonoWaveFile.h"

// Simplified version of WaveFile.
// - Only supports 8bit mono files
// - Only 8bit mono files
// - Static buffer size
// - Suports adjustable playback speed, up to double speed
// - Adjustable playback speed, up to double

#define BITS_PER_SAMPLE 8
#define MAX_BUFFER_LENGTH 256
Expand All @@ -40,19 +40,19 @@ void common_hal_audioio_monowavefile_set_speed(audioio_monowavefile_obj_t *self,
if (speed > 2) {
speed = 2;
}
if (speed < 0) {
if (speed <= 0.1) {
speed = 0.1;
}

LOG("MonoWaveFile: Setting speed: %f\n", (double)speed);
self->stretch_factor = 1 / speed;
self->speed = speed;
}

void common_hal_audioio_monowavefile_construct(audioio_monowavefile_obj_t *self,
pyb_file_obj_t *file,
uint8_t *buffer,
size_t _buffer_size) {
self->stretch_factor = 1.;
self->speed = 1.;
// Load the wave
self->file.handle = file;
uint8_t chunk_header[16];
Expand Down Expand Up @@ -195,7 +195,7 @@ audioio_get_buffer_result_t audioio_monowavefile_get_buffer(
const uint32_t bytes_to_read =
(MAX_BUFFER_LENGTH > self->file.bytes_remaining)
? self->file.bytes_remaining
: (self->stretch_factor * MAX_BUFFER_LENGTH);
: (self->speed * MAX_BUFFER_LENGTH);

LOG("bytes_to_read: %u\n", bytes_to_read);

Expand All @@ -212,7 +212,7 @@ audioio_get_buffer_result_t audioio_monowavefile_get_buffer(

uint32_t target_index = 0;
for (; target_index < MAX_BUFFER_LENGTH; ++target_index) {
const uint32_t source_index = target_index * self->stretch_factor;
const uint32_t source_index = target_index * self->speed;
if (source_index >= read_count) {
break;
}
Expand Down
2 changes: 1 addition & 1 deletion shared-module/audiocore/MonoWaveFile.h
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Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@ typedef struct {
uint16_t buffer_index;

uint32_t sample_rate;
float stretch_factor;
float speed;

} audioio_monowavefile_obj_t;

Expand Down