A simple Arduino API for the libhelix AAC decoder. The data us provided with the help of write() calls. The decoded result is available either via a callback method or via an output stream. More...

#include <AACDecoderHelix.h>

Inheritance diagram for libhelix::AACDecoderHelix:

Public Member Functions
	AACDecoderHelix (Print &output)

	AACDecoderHelix (AACDataCallback dataCallback)

void	setInfoCallback (AACInfoCallback cb, void *caller=nullptr)

void	setDataCallback (AACDataCallback cb)

_AACFrameInfo	audioInfo ()
	Provides the last available _AACFrameInfo_t.

virtual void	end () override
	Releases the reserved memory.

size_t	maxFrameSize () override

size_t	maxPCMSize () override

void	setAudioInfo (int channels, int samplerate)
	Used by M3A format.

void	setOutput (Print &output)

virtual bool	begin ()
	Starts the processing.

virtual size_t	write (const void *in_ptr, size_t in_size)
	decodes the next segments from the input. The data can be provided in one big or in small incremental pieces. It is suggested to be called in the Arduino Loop. If the provided data does not fit into the buffer it is split up into small pieces that fit

	operator bool ()
	returns true if active

uint64_t	timeOfLastWrite ()
	Provides the timestamp in ms of last write.

uint64_t	timeOfLastResult ()
	Provides the timestamp in ms of last decoded result.

void	flush ()
	Decode all open packets.

void	setMaxFrameSize (size_t len)
	Define your optimized maximum frame size in bytes.

void	setMaxPCMSize (size_t len)
	Define your optimized maximum pcm buffer size in bytes.

void	setReference (void *ref)
	Define some additional information which will be provided back in the callbacks.

Protected Member Functions
virtual bool	allocateDecoder () override
	Allocate the decoder.

int	findSynchWord (int offset=0) override
	finds the sync word in the buffer

int	decode () override
	decods the data and removes the decoded frame from the buffer

void	provideResult (_AACFrameInfo &info)

bool	presync ()
	make sure that we start with a valid sync: remove ID3 data

bool	resynch (int rc)

bool	removeInvalidData (int pos)

virtual size_t	writeChunk (const void *in_ptr, size_t in_size)
	Decoding Loop: We decode the procided data until we run out of data.

virtual int	minFrameBufferSize ()
	Provides the actual minimum frame buffer size.

virtual void	setMinFrameBufferSize (int size)
	Defines the minimum frame buffer size which is required before starting the decoding.

Protected Attributes
HAACDecoder	decoder = nullptr

AACDataCallback	pcmCallback = nullptr

AACInfoCallback	infoCallback = nullptr

_AACFrameInfo	aacFrameInfo

void *	p_caller_data = nullptr

bool	active = false

bool	is_raw = false

Vector< uint8_t >	pcm_buffer {0}

SingleBuffer< uint8_t >	frame_buffer {0}

size_t	max_frame_size = 0

size_t	max_pcm_size = 0

size_t	frame_counter = 0

int	delay_ms = -1

int	parse_0_count = 0

int	min_frame_buffer_size = 0

uint64_t	time_last_write = 0

uint64_t	time_last_result = 0

void *	p_caller_ref = nullptr

Print *	out = nullptr

Detailed Description

A simple Arduino API for the libhelix AAC decoder. The data us provided with the help of write() calls. The decoded result is available either via a callback method or via an output stream.

Author: Phil Schatzmann

Copyright: GPLv3

Member Function Documentation

◆ maxFrameSize()

size_t libhelix::AACDecoderHelix::maxFrameSize ( )

inlineoverridevirtual

Provides the maximum frame size in bytes - this is allocated on the heap and you can reduce the heap size my minimizing this value

Implements libhelix::CommonHelix.

◆ maxPCMSize()

size_t libhelix::AACDecoderHelix::maxPCMSize ( )

inlineoverridevirtual

Provides the maximum pcm buffer size in bytes - this is allocated on the heap and you can reduce the heap size my minimizing this value

Implements libhelix::CommonHelix.

◆ removeInvalidData()

bool libhelix::CommonHelix::removeInvalidData ( int pos )

inlineprotectedinherited

removes invalid data not starting with a synch word.

Returns: Returns true if we still have data to be played

◆ resynch()

bool libhelix::CommonHelix::resynch ( int rc )

inlineprotectedinherited

advance on invalid data, returns true if we need to continue the processing

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

src/AACDecoderHelix.h

Public Member Functions