sink.h File Reference

Audio output interface. More...

#include "audio_player/audio.h"

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Data Structures
struct	audio_sink_t

Enumerations
enum	{   SINK_CAP_HW_VOLUME = 1u << 0 , SINK_CAP_DOP = 1u << 1 , SINK_CAP_BITPERFECT = 1u << 2 , SINK_CAP_RATE_SWITCH = 1u << 3 ,   SINK_CAP_DITHERS = 1u << 4 }
	Output resolution. More...

Detailed Description

Audio output interface.

Implemented by the ESP32 port (I2S DAC, Bluetooth through esp32-a2dp-xq), by tests (memory/WAV writer) or by the application (any other output).

Enumeration Type Documentation

anonymous enum

anonymous enum

Output resolution.

The negotiated bits describe the format for the bit-perfect check; the capabilities say how many bits of each Q31 sample really reach the DAC, which sets the DSP dither: SINK_CAP_DITHERS -> no DSP dither (Q31 out), SINK_CAP_BITPERFECT -> at least 24 bits, neither -> the negotiated bits.

Enumerator
SINK_CAP_HW_VOLUME	set_volume_db works; DSP software volume stays off
SINK_CAP_DOP	accepts DoP frames
SINK_CAP_BITPERFECT	Passes the Q31 samples unchanged (at least their top 24 bits, e.g. 32-bit I2S slots) whatever the negotiated bits, so it is bit-perfect when the rates match.
SINK_CAP_RATE_SWITCH	can change sample rate between tracks
SINK_CAP_DITHERS	the sink reduces Q31 to its bit depth with its own TPDF dither