Bluetooth A2DP audio sink: bridge the push pipeline to the pull A2DP source. More...

#include "sink_bluetooth.h"
#include "bluetooth.h"
#include "decoder.h"
#include "freertos/FreeRTOS.h"
#include "freertos/stream_buffer.h"
#include "freertos/task.h"
#include "freertos/timers.h"
#include "freertos/semphr.h"
#include "esp_attr.h"
#include <string.h>
#include <stdint.h>

Macros
#define	SINK_BT_RB_BYTES (21 * 1024)
#define	SINK_BT_WRITE_TO_MS 100 /* give up on a full ring after this (stalled link) */
#define	SINK_BT_FRAME_BYTES 4 /* one 16-bit stereo frame in the ring */
#define	SINK_BT_SUSPEND_DELAY_MS 3000 /* stop->SUSPEND grace: rides out skips and short pauses */

Functions
const audio_sink_t *	sink_bluetooth_get (void)
	Get the Bluetooth A2DP sink (PCM -> ring buffer -> A2DP source -> speaker).

Detailed Description

Bluetooth A2DP audio sink: bridge the push pipeline to the pull A2DP source.

The pipeline pushes PCM via write(); the A2DP source pulls PCM from its own task. A stream buffer decouples the two: write() paces the pipeline by accepting only what fits (the Bluetooth link is the real-time clock). The stack encodes SBC and paces transmission.

The media session outlives one start/stop pair: stop() only arms a deferred SUSPEND and start() cancels it, so a track change (stop+start back-to-back) keeps the stream running. The SUSPEND/CHECK_SRC_RDY/START media commands are asynchronous and unserialised in the stack; issuing a pair of them per skip both added ~1 s of latency and could interleave so the session ended up suspended while the player believed it was playing (silent tracks).

Note: Développé avec l'assistance de Claude Opus 4.8 (Anthropic), sous la direction de Y. Dos Santos : spécification, revue et validation sur cible par l'auteur.

Macro Definition Documentation

◆ SINK_BT_FRAME_BYTES

#define SINK_BT_FRAME_BYTES 4 /* one 16-bit stereo frame in the ring */

◆ SINK_BT_RB_BYTES

#define SINK_BT_RB_BYTES (21 * 1024)

◆ SINK_BT_SUSPEND_DELAY_MS

#define SINK_BT_SUSPEND_DELAY_MS 3000 /* stop->SUSPEND grace: rides out skips and short pauses */

◆ SINK_BT_WRITE_TO_MS

#define SINK_BT_WRITE_TO_MS 100 /* give up on a full ring after this (stalled link) */

Function Documentation

◆ sink_bluetooth_get()

const audio_sink_t * sink_bluetooth_get ( void )

Get the Bluetooth A2DP sink (PCM -> ring buffer -> A2DP source -> speaker).

Returns: Pointer to the static sink vtable (never NULL). start() requires a live Bluetooth connection (see bluetooth_connect()).

Macros

Functions