MetaDataFilter Class Reference

Class which filters out ID3v1 and ID3v2 Metadata and provides only the audio data to the decoder. More...

#include <MetaDataFilter.h>

Inheritance diagram for MetaDataFilter:

Classes
struct	ID3v2Header
	ID3 verion 2 TAG Header (10 bytes) More...

Public Member Functions
	MetaDataFilter ()=default
	Default Constructor.
	MetaDataFilter (AudioWriter &out)
	Constructor which assigns the decoder.
	MetaDataFilter (Print &out)
	Constructor which assigns the decoder.
virtual void	addNotifyAudioChange (AudioInfoSupport &bi)
	Adds target to be notified about audio changes.
virtual AudioInfo	audioInfo () override
	provides the actual input AudioInfo
virtual AudioInfo	audioInfoOut ()
virtual int	availableForWrite () override
bool	begin () override
	(Re)starts the processing
virtual bool	begin (AudioInfo info)
virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.
void	end () override
virtual void	flush ()
virtual bool	isDeletable ()
	If true we need to release the related memory in the destructor.
bool	isNotifyActive ()
	Checks if the automatic AudioInfo update is active.
virtual	operator bool ()
virtual bool	removeNotifyAudioChange (AudioInfoSupport &bi)
	Removes a target in order not to be notified about audio changes.
virtual void	setAudioInfo (AudioInfo newInfo) override
	Defines the input AudioInfo.
void	setNotifyActive (bool flag)
	Deactivate/Reactivate automatic AudioInfo updates: (default is active)
void	setOutput (AudioWriter &out)
	Defines the decoder to which we write the data.
void	setOutput (Print &out)
	Defines the decoder to which we write the data.
size_t	write (const uint8_t *data, size_t len) override
	Writes the data to the decoder.
virtual size_t	write (uint8_t ch) override
virtual void	writeSilence (size_t len)

Protected Member Functions
uint32_t	calcSizeID3v2 (uint8_t chars[4])
void	checkID3v2Header (const uint8_t *data, size_t len)
void	flushTail ()
void	notifyAudioChange (AudioInfo info)
size_t	writeOut (const uint8_t *data, size_t len)

Protected Attributes
int	_timeout = 10
AudioInfo	cfg
int	id3v2_skip_remaining = 0
	remaining bytes of a leading ID3v2 tag still to be dropped
bool	is_active = false
bool	is_notify_active = true
Vector< AudioInfoSupport * >	notify_vector
SingleBuffer< uint8_t >	out_buf
	reused scratch buffer for the bytes flushed out of the tail per write()
Print *	p_out = nullptr
AudioWriter *	p_writer = nullptr
RingBuffer< uint8_t >	tail {kMaxTailLen}
SingleBuffer< uint8_t >	tmp {MAX_SINGLE_CHARS}
int	tmpPos = 0
uint64_t	total_pos = 0
	total number of input bytes seen so far (absolute stream position)

Static Protected Attributes
static const int	kID3v1EnhancedLen = 227
static const int	kID3v1Len = 128
static const int	kMaxTailLen = kID3v1Len + kID3v1EnhancedLen

Detailed Description

Class which filters out ID3v1 and ID3v2 Metadata and provides only the audio data to the decoder.

Author

Phil Schatzmann

Copyright

GPLv3

Constructor & Destructor Documentation

MetaDataFilter() [1/3]

MetaDataFilter ( )

default

Default Constructor.

MetaDataFilter() [2/3]

MetaDataFilter ( Print &  out )

inline

Constructor which assigns the decoder.

MetaDataFilter() [3/3]

MetaDataFilter ( AudioWriter &  out )

inline

Constructor which assigns the decoder.

Member Function Documentation

addNotifyAudioChange()

virtual void addNotifyAudioChange ( AudioInfoSupport &  bi )

inlinevirtualinherited

Adds target to be notified about audio changes.

Reimplemented in CodecNOP, EncodedAudioOutput, EncodedAudioStream, AACDecoderFDK, DecoderBasic, CodecChain, MP3DecoderHelix, MP3DecoderMAD, OggContainerDecoder, RTSPClient< TcpClient, UdpSocket >, Pipeline, and Pipeline::ModifyingStreamAdapter.

audioInfo()

virtual AudioInfo audioInfo ( )

inlineoverridevirtualinherited

provides the actual input AudioInfo

Implements AudioInfoSupport.

Reimplemented in AdapterPrintToAudioOutput, EncodedAudioOutput, and AdapterAudioStreamToAudioOutput.

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 MP3EncoderShine, PureDataStream, PWMAudioOutput< PWMDriverT >, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, FormatConverterStream, Pipeline, ResampleStream, and ResampleStreamT< TInterpolator >.

availableForWrite()

virtual int availableForWrite ( )

inlineoverridevirtualinherited

Reimplemented from Print.

Reimplemented in AudioESP32ULP, RTSPOutput< Platform >, SPIAudioMaster, EncodedAudioOutput, AudioServerEx, AudioSyncWriter, AdapterAudioStreamToAudioOutput, CsvOutput< T >, MemoryOutput, and PWMAudioOutput< PWMDriverT >.

begin() [1/2]

bool begin ( )

inlineoverridevirtual

(Re)starts the processing

Reimplemented from AudioOutput.

begin() [2/2]

virtual bool begin ( AudioInfo  info )

inlinevirtualinherited

Reimplemented in AudioESP32ULP, RTSPOutput< Platform >, RTTTLOutput< T >, ChannelsSelectOutput, CsvOutput< T >, and EncodedAudioOutput.

calcSizeID3v2()

uint32_t calcSizeID3v2 ( uint8_t  chars[4] )

inlineprotected

checkID3v2Header()

void checkID3v2Header ( const uint8_t *  data, size_t  len  )

inlineprotected

checks for a ID3v2 header at the start of the stream and, if found, arranges for its bytes (header + body) to be skipped

clearNotifyAudioChange()

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

end()

void end ( )

inlineoverridevirtual

Reimplemented from AudioOutput.

flush()

virtual void flush ( )

inlinevirtualinherited

Reimplemented from Print.

Reimplemented in MultiOutput, and HexDumpOutput.

flushTail()

void flushTail ( )

inlineprotected

checks the buffered tail (the real end of the stream) for a trailing ID3v1 ("TAG") tag, optionally preceded by an enhanced ("TAG+") tag, and writes out whatever is left over as regular audio data

isDeletable()

virtual bool isDeletable ( )

inlinevirtualinherited

If true we need to release the related memory in the destructor.

Reimplemented in AdapterPrintToAudioOutput, and AdapterAudioStreamToAudioOutput.

isNotifyActive()

bool isNotifyActive ( )

inlineinherited

Checks if the automatic AudioInfo update is active.

notifyAudioChange()

void notifyAudioChange ( AudioInfo  info )

inlineprotectedinherited

operator bool()

virtual operator bool ( )

inlinevirtualinherited

Reimplemented in RTSPOutput< Platform >, EncodedAudioOutput, and AdapterAudioStreamToAudioOutput.

removeNotifyAudioChange()

virtual bool removeNotifyAudioChange ( AudioInfoSupport &  bi )

inlinevirtualinherited

Removes a target in order not to be notified about audio changes.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

setAudioInfo()

virtual void setAudioInfo ( AudioInfo  info )

inlineoverridevirtualinherited

Defines the input AudioInfo.

Implements AudioInfoSupport.

Reimplemented in ChannelsSelectOutput, AdapterPrintToAudioOutput, MultiOutput, SPIAudioMaster, AdapterAudioStreamToAudioOutput, CsvOutput< T >, PWMAudioOutput< PWMDriverT >, and EncodedAudioOutput.

setNotifyActive()

void setNotifyActive ( bool  flag )

inlineinherited

Deactivate/Reactivate automatic AudioInfo updates: (default is active)

setOutput() [1/2]

void setOutput ( AudioWriter &  out )

inline

Defines the decoder to which we write the data.

setOutput() [2/2]

void setOutput ( Print &  out )

inline

Defines the decoder to which we write the data.

write() [1/2]

size_t write ( const uint8_t *  data, size_t  len  )

inlineoverridevirtual

Writes the data to the decoder.

Implements AudioOutput.

write() [2/2]

virtual size_t write ( uint8_t  ch )

inlineoverridevirtualinherited

Reimplemented in MetaDataOutput, and MultiOutput.

writeOut()

size_t writeOut ( const uint8_t *  data, size_t  len  )

inlineprotected

writeSilence()

virtual void writeSilence ( size_t  len )

inlinevirtualinherited

Writes n 0 values (= silence)

Parameters

len

Member Data Documentation

_timeout

int _timeout = 10

protectedinherited

cfg

AudioInfo cfg

protectedinherited

id3v2_skip_remaining

int id3v2_skip_remaining = 0

protected

remaining bytes of a leading ID3v2 tag still to be dropped

is_active

bool is_active = false

protectedinherited

is_notify_active

bool is_notify_active = true

protectedinherited

kID3v1EnhancedLen

const int kID3v1EnhancedLen = 227

staticprotected

kID3v1Len

const int kID3v1Len = 128

staticprotected

kMaxTailLen

const int kMaxTailLen = kID3v1Len + kID3v1EnhancedLen

staticprotected

notify_vector

Vector<AudioInfoSupport*> notify_vector

protectedinherited

out_buf

SingleBuffer<uint8_t> out_buf

protected

reused scratch buffer for the bytes flushed out of the tail per write()

p_out

Print* p_out = nullptr

protected

p_writer

AudioWriter* p_writer = nullptr

protected

tail

RingBuffer<uint8_t> tail {kMaxTailLen}

protected

delay line holding the last (at most) kMaxTailLen bytes: needed because a trailing ID3v1/TAG+ tag can only be recognized once we know we are at the actual end of the stream

tmp

SingleBuffer<uint8_t> tmp {MAX_SINGLE_CHARS}

protectedinherited

tmpPos

int tmpPos = 0

protectedinherited

total_pos

uint64_t total_pos = 0

protected

total number of input bytes seen so far (absolute stream position)

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

• src/AudioTools/CoreAudio/AudioMetaData/MetaDataFilter.h