libhelix::AACDecoderHelix Class Reference

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 short 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
virtual void	setDelay (int delayMs)
	Defines the delay that is added at each segment.
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 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	setRaw (bool)
	Obsolete!

Protected Member Functions
int	minFrameBufferSize () override
	Prevent error in underflow detection of decode.
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)

Protected Attributes
HAACDecoder	decoder = nullptr
AACDataCallback	pcmCallback = nullptr
AACInfoCallback	infoCallback = nullptr
_AACFrameInfo	aacFrameInfo
void *	p_caller_ref = nullptr
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
uint64_t	time_last_write = 0
uint64_t	time_last_result = 0
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

writeChunk()

virtual size_t libhelix::CommonHelix::writeChunk ( const void *  in_ptr, size_t  in_size  )

inlineprotectedvirtualinherited

Prevent bug in underflow detection for AAC

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

• src/AACDecoderHelix.h