ascii-chat Client Audio Processing Management Interface More...

Functions
void	audio_process_received_samples (const float *samples, int num_samples)
	Process received audio samples from server.

int	audio_client_init (void)
	Initialize audio subsystem.

void	audio_sender_init (void)
	Initialize audio sender thread.

void	audio_sender_cleanup (void)
	Cleanup async audio sender.

void	audio_sender_finalize (void)

int	audio_start_thread (void)
	Start audio capture thread.

void	audio_stop_thread (void)
	Stop audio capture thread.

bool	audio_thread_exited (void)
	Check if audio capture thread has exited.

void	audio_cleanup (void)
	Cleanup audio subsystem.

client_audio_pipeline_t *	audio_get_pipeline (void)
	Get the audio pipeline (for advanced usage)

int	audio_decode_opus (const uint8_t opus_data, size_t opus_len, float output, int max_samples)
	Decode Opus packet using the audio pipeline.

audio_context_t *	audio_get_context (void)
	Get the global audio context for use by other subsystems.

Detailed Description

ascii-chat Client Audio Processing Management Interface

Defines the interface for audio system initialization, capture thread management, and audio sample processing in the ascii-chat client.

The audio subsystem handles bidirectional audio streaming using Opus encoding and PortAudio for platform-independent audio capture and playback.

Audio Pipeline

Capture: Microphone → PortAudio → Opus encoder → Send to server
Playback: Server packet → Opus decoder → Ring buffer → PortAudio → Speaker

Configuration

Options:

--audio: Enable audio (disabled by default)
--audio-device <index>: Select audio input/output device

Parameters:

Sample rate: 44100 Hz
Channels: 1 (mono)
Format: 32-bit float samples
Opus bitrate: Variable (16-48 kbps)
Batch size: 256 samples (~5.8ms at 44.1kHz)
Ring buffer: 8192 samples (~185ms jitter buffer)

Author: Zachary Fogg me@zf.nosp@m.o.gg

Date: 2025

See also: topic_client_audio "Audio Architecture"

Definition in file src/client/audio.h.

Function Documentation

◆ audio_sender_cleanup()

void audio_sender_cleanup ( void )

Cleanup async audio sender.

Signal the asynchronous audio sender to stop before worker threads are joined.

Definition at line 387 of file src/client/audio.c.

                                {
  // Signal thread to exit
  if (lifecycle_is_initialized(&g_audio_send_queue_lc)) {
    atomic_store_bool(&g_audio_sender_should_exit, true);
    mutex_lock(&g_audio_send_queue_mutex);
    cond_signal(&g_audio_send_queue_cond);
    mutex_unlock(&g_audio_send_queue_mutex);
  }
 
  // The worker is joined by thread_pool_stop_all() in protocol_stop_connection().
  // Keep the queue synchronization objects alive until that join completes.
  if (THREAD_IS_CREATED(g_audio_sender_thread_created)) {
    log_debug("Audio sender thread will be joined by thread pool");
  }
}

References atomic_store_bool(), cond_signal(), lifecycle_is_initialized(), log_debug, mutex_lock, mutex_unlock, and THREAD_IS_CREATED.

Referenced by audio_cleanup(), and protocol_stop_connection().

◆ audio_sender_finalize()

void audio_sender_finalize ( void )

Release asynchronous audio sender resources after its worker has been joined.

Definition at line 403 of file src/client/audio.c.

                                 {
  if (!lifecycle_is_initialized(&g_audio_send_queue_lc)) {
    return;
  }
 
  // thread_pool_stop_all() normally joins this worker. If the sender was
  // blocked in transport I/O when the pool timeout elapsed, wait for the
  // shutdown signal to be observed before destroying its queue mutex.
  for (int i = 0; i < 200 && !atomic_load_bool(&g_audio_sender_exited); i++) {
    platform_sleep_us(10 * US_PER_MS_INT);
  }
  if (!atomic_load_bool(&g_audio_sender_exited)) {
    log_warn("Audio sender thread did not exit before queue cleanup");
    return;
  }
 
  mutex_destroy(&g_audio_send_queue_mutex);
  cond_destroy(&g_audio_send_queue_cond);
  lifecycle_shutdown(&g_audio_send_queue_lc);
  g_audio_sender_thread_created = false;
}

References atomic_load_bool(), cond_destroy(), lifecycle_is_initialized(), lifecycle_shutdown(), log_warn, mutex_destroy(), platform_sleep_us(), and US_PER_MS_INT.