A2DPDecoderSBC Class Reference

SBC decode support for the managed A2DP decoder framework: wraps any audio_tools::AudioDecoder that decodes SBC - e.g. audio_tools::SBCDecoder (arduino-libsbc) - and advertises the SBC SEP capability. Construct your decoder of choice, include its codec header yourself (e.g. "AudioTools/AudioCodecs/CodecSBC.h"), and register an A2DPDecoderSBC wrapping it via BluetoothA2DPSink::add_decoder(). More...

#include <A2DPDecoderSBC.h>

Inheritance diagram for A2DPDecoderSBC:

Public Member Functions
	A2DPDecoderSBC (audio_tools::AudioDecoder &decoder)
virtual bool	begin (const esp_a2d_mcc_t &mcc)
void	build_capability (esp_a2d_mcc_t &mcc) override
	Fills in the SEP capability advertised for this codec at registration.
esp_a2d_mct_t	codec_type () override
	A2DP codec type this decoder handles (e.g. ESP_A2D_MCT_SBC)
virtual void	end ()
	Closes the wrapped audio_tools decoder.
audio_tools::AudioInfo	get_audio_info ()
const char *	mime () override
	MIME type of the codec this decoder handles (e.g. "audio/sbc")
virtual size_t	write (const uint8_t *data, size_t len)

Protected Member Functions
void	parse_audio_info (const esp_a2d_mcc_t &mcc) override

Protected Attributes
int	bits_per_sample = 16
int	channels = 2
audio_tools::AudioDecoder *	p_decoder
audio_tools::CallbackStream	pcm_stream
int	sample_rate = 44100

Detailed Description

SBC decode support for the managed A2DP decoder framework: wraps any audio_tools::AudioDecoder that decodes SBC - e.g. audio_tools::SBCDecoder (arduino-libsbc) - and advertises the SBC SEP capability. Construct your decoder of choice, include its codec header yourself (e.g. "AudioTools/AudioCodecs/CodecSBC.h"), and register an A2DPDecoderSBC wrapping it via BluetoothA2DPSink::add_decoder().

Author

Phil Schatzmann

Copyright

Apache License Version 2

Member Function Documentation

begin()

virtual bool A2DPDecoder::begin ( const esp_a2d_mcc_t &  mcc )

inlinevirtualinherited

Opens the wrapped audio_tools decoder for the negotiated SEP capability: calls parse_audio_info(mcc) (implemented per codec - most decoders self-detect sample rate/channels from the encoded stream and can leave sample_rate/channels at their defaults, but codecs whose wire format doesn't carry that info per-frame, e.g. AAC, need it to synthesize the framing their decoder expects - see A2DPDecoderAAC), then wires up the PCM output and audio-info-change notification and starts the decoder.

build_capability()

void A2DPDecoderSBC::build_capability ( esp_a2d_mcc_t &  mcc )

inlineoverridevirtual

Fills in the SEP capability advertised for this codec at registration.

Implements A2DPDecoder.

codec_type()

esp_a2d_mct_t A2DPDecoderSBC::codec_type ( )

inlineoverridevirtual

A2DP codec type this decoder handles (e.g. ESP_A2D_MCT_SBC)

Implements A2DPDecoder.

get_audio_info()

audio_tools::AudioInfo A2DPDecoder::get_audio_info ( )

inlineinherited

Returns the most recently detected sample rate/channels (default AudioInfo values until the wrapped decoder has actually parsed them from the encoded stream)

mime()

const char * A2DPDecoderSBC::mime ( )

inlineoverridevirtual

MIME type of the codec this decoder handles (e.g. "audio/sbc")

Implements A2DPDecoder.

parse_audio_info()

void A2DPDecoderSBC::parse_audio_info ( const esp_a2d_mcc_t &  mcc )

inlineoverrideprotectedvirtual

determines sample_rate/channels from the negotiated SBC capability (a single bit is set per field once negotiation completes); the wrapped decoder also self-detects the same values from the SBC frame header itself once frames start flowing (see A2DPDecoder::get_audio_info())

Implements A2DPDecoder.

write()

virtual size_t A2DPDecoder::write ( const uint8_t *  data, size_t  len  )

inlinevirtualinherited

Feeds raw encoded bytes to the wrapped decoder; decoded PCM is forwarded automatically via pcm_stream

Reimplemented in A2DPDecoderAAC.

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The documentation for this class was generated from the following file:

• src/A2DPDecoderSBC.h