From 305c396ea75aad1462c604297beec90840dfbc16 Mon Sep 17 00:00:00 2001 From: Damien George Date: Mon, 9 Sep 2024 13:14:32 +1000 Subject: [PATCH] codal_port/modaudio: Improve feeding of audio pipeline. Signed-off-by: Damien George --- src/codal_port/modaudio.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/src/codal_port/modaudio.c b/src/codal_port/modaudio.c index b4b7c70..e22cf37 100644 --- a/src/codal_port/modaudio.c +++ b/src/codal_port/modaudio.c @@ -37,7 +37,7 @@ #define audio_source_iter MP_STATE_PORT(audio_source_iter_state) #ifndef AUDIO_OUTPUT_BUFFER_SIZE -#define AUDIO_OUTPUT_BUFFER_SIZE (32) +#define AUDIO_OUTPUT_BUFFER_SIZE (64) #endif #define DEFAULT_AUDIO_FRAME_SIZE (32) @@ -56,6 +56,8 @@ static size_t audio_source_frame_offset; static uint32_t audio_current_sound_level; static mp_sched_node_t audio_data_fetcher_sched_node; +static void audio_data_schedule_fetch(void); + static inline bool audio_is_running(void) { return audio_source_frame != NULL || audio_source_track != NULL || audio_source_iter != MP_OBJ_NULL; } @@ -169,7 +171,7 @@ static void audio_data_fetcher(mp_sched_node_t *node) { if (audio_output_buffer_offset < AUDIO_OUTPUT_BUFFER_SIZE) { // Output buffer not full yet, so attempt to pull more data from the source. - mp_sched_schedule_node(&audio_data_fetcher_sched_node, audio_data_fetcher); + audio_data_schedule_fetch(); } else { // Output buffer is full, process it and prepare for next buffer fill. audio_output_buffer_offset = 0; @@ -192,6 +194,18 @@ static void audio_data_fetcher(mp_sched_node_t *node) { } } +static void audio_data_schedule_fetch(void) { + if (audio_source_track != NULL && audio_source_frame_offset < audio_source_track->size) { + // An existing AudioTrack is being played, and still has some data remaining, + // so fetch that immediately. This helps to keep audio playback smooth when the + // playback rate is large. + audio_data_fetcher(&audio_data_fetcher_sched_node); + } else { + // Schedule audio_data_fetcher to be executed ASAP to try and fetch more data. + mp_sched_schedule_node(&audio_data_fetcher_sched_node, audio_data_fetcher); + } +} + void microbit_hal_audio_raw_ready_callback(void) { if (audio_output_state == AUDIO_OUTPUT_STATE_DATA_READY) { // there is data ready to send out to the audio pipeline, so send it @@ -202,8 +216,8 @@ void microbit_hal_audio_raw_ready_callback(void) { audio_output_state = AUDIO_OUTPUT_STATE_IDLE; } - // schedule audio_data_fetcher to be executed to prepare the next buffer - mp_sched_schedule_node(&audio_data_fetcher_sched_node, audio_data_fetcher); + // Schedule the next fetch of audio data. + audio_data_schedule_fetch(); } static void audio_init(uint32_t sample_rate) {