EncoderALAC Class Reference

ALAC (Apple Lossless Audio Codec) encoder. This class is responsible for encoding audio data into ALAC format. The implementaion is based on https://github.com/macosforge/alac. More...

#include <CodecALAC.h>

Inheritance diagram for EncoderALAC:

Public Member Functions
	EncoderALAC (int frameSize=kALACDefaultFrameSize)
	Default constructor: you can define your own optimized frame size.
AudioInfo	audioInfo () override
	provides the actual input AudioInfo
virtual AudioInfo	audioInfoOut ()
bool	begin () override
virtual bool	begin (AudioInfo info)
ALACBinaryConfig &	binaryConfig ()
	Provide the magic coookie for the decoder.
ALACSpecificConfig	config ()
	Provide the configuration of the encoder.
void	end () override
virtual uint32_t	frameDurationUs ()
	Optional rtsp function: provide the frame duration in microseconds.
int	frameSize ()
	Determins the actually defined number of frames.
const char *	mime () override
	Mime type: returns audio/alac.
	operator bool ()
	Check if the encoder is ready to encode.
virtual uint16_t	samplesPerFrame ()
	Optional rtsp function: provide samples per the frame.
void	setAudioInfo (AudioInfo from) override
	Defines the sample rate, number of channels and bits per sample.
void	setFastMode (bool fast)
	Defines if the encoder should use fast mode.
void	setFrameSize (int frames)
	Defines the frame size for the decoder: default is 4096 frames.
void	setOutput (Print &out_stream) override
	Default output assignment (encoders may override to store Print reference)
size_t	write (const uint8_t *data, size_t len) override
	Encode the audio samples into ALAC format.

Protected Types
enum	{ kFormatFlag_16BitSourceData = 1 , kFormatFlag_20BitSourceData = 2 , kFormatFlag_24BitSourceData = 3 , kFormatFlag_32BitSourceData = 4 }

Protected Member Functions
AudioFormatDescription	getInputFormat ()
AudioFormatDescription	getOutputFormat ()
uint32_t	getOutputFormatFlags (uint32_t bits)
void	writeBlocking (Print *out, uint8_t *data, size_t len)

Protected Attributes
ALACBinaryConfig	bin
ALACSpecificConfig	cfg
ALACEncoder	enc
int	frame_size = kALACDefaultFrameSize
SingleBuffer< uint8_t >	in_buffer
AudioInfo	info
AudioFormatDescription	input_format
bool	is_started = false
Vector< uint8_t >	out_buffer
AudioFormatDescription	out_format
Print *	p_print = nullptr

Detailed Description

ALAC (Apple Lossless Audio Codec) encoder. This class is responsible for encoding audio data into ALAC format. The implementaion is based on https://github.com/macosforge/alac.

Author

Phil Schatzmann

Member Function Documentation

audioInfo()

AudioInfo audioInfo ( )

inlineoverridevirtualinherited

provides the actual input AudioInfo

Implements AudioInfoSupport.

Reimplemented in CodecNOP, BinaryContainerEncoder, and MP3ParserEncoder.

audioInfoOut()

virtual AudioInfo audioInfoOut ( )

inlinevirtualinherited

provides the actual output AudioInfo: this is usually the same as audioInfo() unless we use a transforming stream

Reimplemented in PureDataStream, PWMAudioOutput, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, FormatConverterStream, Pipeline, ResampleStream, and ResampleStreamT< TInterpolator >.

begin() [1/2]

bool begin ( )

inlineoverridevirtual

Implements AudioWriter.

begin() [2/2]

virtual bool begin ( AudioInfo  info )

inlinevirtualinherited

Reimplemented in AACEncoderFDK.

end()

void end ( )

inlineoverridevirtual

Implements AudioWriter.

frameDurationUs()

virtual uint32_t frameDurationUs ( )

inlinevirtualinherited

Optional rtsp function: provide the frame duration in microseconds.

Reimplemented in ADPCMEncoder, OpusOggEncoder, MP3ParserEncoder, and MetaDataFilterEncoder.

mime()

const char * mime ( )

inlineoverridevirtual

Mime type: returns audio/alac.

Implements AudioEncoder.

operator bool()

operator bool ( )

inlinevirtual

Check if the encoder is ready to encode.

Implements AudioWriter.

samplesPerFrame()

virtual uint16_t samplesPerFrame ( )

inlinevirtualinherited

Optional rtsp function: provide samples per the frame.

Reimplemented in MP3ParserEncoder, and MetaDataFilterEncoder.

setAudioInfo()

void setAudioInfo ( AudioInfo  from )

inlineoverridevirtualinherited

Defines the sample rate, number of channels and bits per sample.

Implements AudioWriter.

Reimplemented in MP3EncoderLAME, EncoderBasic, CodecChain, FLACEncoder, OpusAudioEncoder, WAVEncoder, CodecNOP, G7xxEncoder, BinaryContainerEncoder, OggContainerEncoder, OSCContainerEncoder, and MetaDataFilterEncoder.

setOutput()

void setOutput ( Print &  out_stream )

inlineoverridevirtual

Default output assignment (encoders may override to store Print reference)

Reimplemented from AudioEncoder.

write()

size_t write ( const uint8_t *  data, size_t  len  )

inlineoverridevirtual

Encode the audio samples into ALAC format.

Implements AudioWriter.

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

• src/AudioTools/AudioCodecs/CodecALAC.h