StreamingDecoder Class Reference

A Streaming Decoder where we provide both the input and output as streams. More...

#include <StreamingDecoder.h>

Inheritance diagram for StreamingDecoder:

Public Member Functions
virtual void	addNotifyAudioChange (AudioInfoSupport &bi)
	Adds target to be notified about audio changes.
virtual AudioInfo	audioInfo ()=0
	Provides the audio information for the current stream.
virtual AudioInfo	audioInfoOut ()
virtual bool	begin ()=0
	Starts the processing.
virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.
virtual bool	copy ()=0
	Process a single read operation - to be called in the loop.
bool	copyAll ()
	Process all available data.
virtual void	end ()=0
	Releases the reserved memory.
bool	isNotifyActive ()
	Checks if the automatic AudioInfo update is active.
virtual const char *	mime ()=0
	Provides the MIME type of the audio format handled by this decoder.
virtual	operator bool ()=0
	Checks if the class is active.
virtual bool	removeNotifyAudioChange (AudioInfoSupport &bi)
	Removes a target in order not to be notified about audio changes.
void	setInput (Stream &inStream)
	Stream Interface: Decode directly by taking data from the stream.
void	setNotifyActive (bool flag)
	Deactivate/Reactivate automatic AudioInfo updates: (default is active)
virtual void	setOutput (AudioOutput &out_stream)
	Defines the output streams and register to be notified.
virtual void	setOutput (AudioStream &out_stream)
	Defines the output streams and register to be notified.
virtual void	setOutput (Print &out_stream)
	Defines the output Stream.

Protected Member Functions
void	notifyAudioChange (AudioInfo info)
virtual size_t	readBytes (uint8_t *data, size_t len)=0
	Reads bytes from the input stream.
void	setAudioInfo (AudioInfo newInfo) override
	Defines the input AudioInfo.

Protected Attributes
AudioInfo	info
bool	is_notify_active = true
Vector< AudioInfoSupport * >	notify_vector
Stream *	p_input = nullptr
	Input stream for encoded audio data.
Print *	p_print = nullptr
	Output stream for decoded PCM data.

Detailed Description

A Streaming Decoder where we provide both the input and output as streams.

This is the base class for all streaming decoders that process audio data by reading from an input stream and writing decoded PCM data to an output stream. Unlike AudioDecoder which uses a write-based interface, StreamingDecoder uses a pull-based approach where you call copy() to process data.

Note

This is more efficient than the write-based AudioDecoder interface for streaming scenarios where you have direct access to input and output streams.

Author

Phil Schatzmann

Copyright

GPLv3

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, Pipeline, and Pipeline::ModifyingStreamAdapter.

audioInfo()

virtual AudioInfo audioInfo ( )

pure virtual

Provides the audio information for the current stream.

Returns audio format information such as sample rate, channels, and bits per sample that was determined from the decoded audio stream.

Returns

AudioInfo structure containing format information

Implements AudioInfoSupport.

Implemented in FLACDecoder, VorbisDecoder, StreamingDecoderAdapter, MultiStreamingDecoder, and VorbisDecoder.

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()

virtual bool begin ( )

pure virtual

Starts the processing.

Initializes the decoder and prepares it for processing audio data. Must be called before any copy() operations.

Returns

true if initialization was successful, false otherwise

Implemented in FLACDecoder, VorbisDecoder, StreamingDecoderAdapter, MultiStreamingDecoder, and VorbisDecoder.

copy()

virtual bool copy ( )

pure virtual

Process a single read operation - to be called in the loop.

Reads a chunk of data from the input stream, decodes it, and writes the decoded PCM data to the output stream.

Returns

true if data was processed successfully, false if no more data is available or an error occurred

Implemented in FLACDecoder, VorbisDecoder, StreamingDecoderAdapter, and MultiStreamingDecoder.

copyAll()

bool copyAll ( )

inline

Process all available data.

Convenience method that calls copy() repeatedly until all available data has been processed.

Returns

true if any data was processed, false if no data was available

end()

virtual void end ( )

pure virtual

Releases the reserved memory.

Cleans up any resources allocated by the decoder and stops processing.

Implemented in FLACDecoder, VorbisDecoder, StreamingDecoderAdapter, MultiStreamingDecoder, and VorbisDecoder.

mime()

virtual const char * mime ( )

pure virtual

Provides the MIME type of the audio format handled by this decoder.

Returns

C-string containing the MIME type (e.g., "audio/mpeg", "audio/flac")

Implemented in FLACDecoder, VorbisDecoder, StreamingDecoderAdapter, and MultiStreamingDecoder.

operator bool()

virtual operator bool ( )

pure virtual

Checks if the class is active.

Returns

true if the decoder is ready and active, false otherwise

Implemented in FLACDecoder, VorbisDecoder, StreamingDecoderAdapter, MultiStreamingDecoder, and VorbisDecoder.

readBytes()

virtual size_t readBytes ( uint8_t *  data, size_t  len  )

protectedpure virtual

Reads bytes from the input stream.

Derived classes must implement this to read data from their input source.

Parameters

data	Buffer to store the read data
len	Maximum number of bytes to read

Returns

Number of bytes actually read

Implemented in FLACDecoder, VorbisDecoder, StreamingDecoderAdapter, and MultiStreamingDecoder.

setAudioInfo()

void setAudioInfo ( AudioInfo  info )

inlineoverrideprotectedvirtual

Defines the input AudioInfo.

Implements AudioInfoSupport.

setInput()

void setInput ( Stream &  inStream )

inline

Stream Interface: Decode directly by taking data from the stream.

This is more efficient than feeding the decoder with write: just call copy() in the loop to process data from the input stream.

Parameters

inStream

The input stream containing encoded audio data

setOutput() [1/3]

virtual void setOutput ( AudioOutput &  out_stream )

inlinevirtual

Defines the output streams and register to be notified.

Sets the output stream and registers for audio info change notifications.

Parameters

out_stream

The AudioOutput to write decoded audio data to

Reimplemented in MultiStreamingDecoder.

setOutput() [2/3]

virtual void setOutput ( AudioStream &  out_stream )

inlinevirtual

Defines the output streams and register to be notified.

Sets the output stream and registers for audio info change notifications.

Parameters

out_stream

The AudioStream to write decoded audio data to

Reimplemented in MultiStreamingDecoder.

setOutput() [3/3]

virtual void setOutput ( Print &  out_stream )

inlinevirtual

Defines the output Stream.

Sets where the decoded PCM audio data will be written to.

Parameters

out_stream

The Print stream to write decoded audio data to

Reimplemented in StreamingDecoderAdapter, and MultiStreamingDecoder.

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

• src/AudioTools/AudioCodecs/StreamingDecoder.h