MP3EncoderLAME Class Reference

Encodes PCM data to the MP3 format and writes the result to a stream This is basically just a wrapper using https://github.com/pschatzmann/codec-lame. More...

#include <CodecMP3LAME.h>

Inheritance diagram for MP3EncoderLAME:

Classes
class	FrameWriter
	Receives the output of LAME and passes it on in complete MP3 frames. More...

Public Member Functions
	MP3EncoderLAME (bool splitFrames=false)
	MP3EncoderLAME (Print &out_stream, bool splitFrames=false)
	~MP3EncoderLAME ()
AudioInfo	audioInfo () override
	provides the actual input AudioInfo
AudioInfoLAME &	audioInfoExt ()
virtual AudioInfo	audioInfoOut ()
bool	begin ()
virtual bool	begin (AudioInfo info)
bool	begin (AudioInfoLAME from)
AudioInfoLAME	defaultConfig ()
liblame::MP3EncoderLAME *	driver ()
void	end ()
virtual uint32_t	frameDurationUs ()
	Optional rtsp function: provide the frame duration in microseconds.
virtual int	frameSize ()
const char *	mime ()
	Provides the mime type of the encoded result.
virtual	operator bool ()
virtual uint16_t	samplesPerFrame ()
	Optional rtsp function: provide samples per the frame.
void	setAudioInfo (AudioInfo from)
	Defines the Audio Info.
void	setAudioInfo (AudioInfoLAME from)
	Defines the Audio Info.
void	setOutput (Print &out_stream)
	Defines the output stream.
size_t	write (const uint8_t *data, size_t len)

Protected Member Functions
void	createEnc ()
void	writeBlocking (Print *out, uint8_t *data, size_t len)

Protected Attributes
liblame::MP3EncoderLAME *	enc =nullptr
FrameWriter	frame_writer {frames}
HeaderParserMP3	frames
AudioInfo	info
AudioInfoLAME	lame_info
Print *	p_print =nullptr
bool	split_frames = false

Static Protected Attributes
static constexpr int	kMaxFrameSize = 2048
	Buffer size for the frame splitting: bigger than the largest MP3 frame.

Detailed Description

Encodes PCM data to the MP3 format and writes the result to a stream This is basically just a wrapper using https://github.com/pschatzmann/codec-lame.

LAME delivers its output in arbitrary chunks (zero, one or several MP3 frames per write()). Pass splitFrames = true to the constructor to get exactly one complete MP3 frame per write() to the output instead - as e.g. the video muxers (MuxerMTS, MuxerAVI, ...) expect it.

Author

Phil Schatzmann

Copyright

GPLv3

Constructor & Destructor Documentation

MP3EncoderLAME() [1/2]

MP3EncoderLAME ( bool  splitFrames = false )

inline

Parameters

splitFrames

true: write exactly one complete MP3 frame per write()

MP3EncoderLAME() [2/2]

MP3EncoderLAME ( Print &  out_stream, bool  splitFrames = false  )

inline

Parameters

splitFrames

true: write exactly one complete MP3 frame per write()

~MP3EncoderLAME()

~MP3EncoderLAME ( )

inline

Member Function Documentation

audioInfo()

AudioInfo audioInfo ( )

inlineoverridevirtualinherited

provides the actual input AudioInfo

Implements AudioInfoSupport.

Reimplemented in CodecNOP, MP3EncoderShine, BinaryContainerEncoder, and MP3ParserEncoder.

audioInfoExt()

AudioInfoLAME & audioInfoExt ( )

inline

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, ResampleStreamT< TInterpolator >, and SupportedRatesStream.

begin() [1/3]

bool begin ( )

inlinevirtual

Implements AudioWriter.

begin() [2/3]

virtual bool begin ( AudioInfo  info )

inlinevirtualinherited

Reimplemented in OpusOggEncoder, OggContainerEncoder, DecoderBasic, AudioDecoder, AACEncoderFAAC, AACEncoderFDK, AACEncoderVO, OggContainerDecoder, and MetaDataFilterEncoder.

begin() [3/3]

bool begin ( AudioInfoLAME  from )

inline

createEnc()

void createEnc ( )

inlineprotected

defaultConfig()

AudioInfoLAME defaultConfig ( )

inline

driver()

liblame::MP3EncoderLAME * driver ( )

inline

end()

void end ( )

inlinevirtual

Implements AudioWriter.

frameDurationUs()

virtual uint32_t frameDurationUs ( )

inlinevirtualinherited

Optional rtsp function: provide the frame duration in microseconds.

Reimplemented in ADPCMEncoder, MP3EncoderShine, OpusOggEncoder, MP3ParserEncoder, and MetaDataFilterEncoder.

frameSize()

virtual int frameSize ( )

inlinevirtualinherited

Optional rtsp function: provide the encoded size (in bytes) of one frame, once known (e.g. after the encoder has seen real data). Lets an RTSPFormat size its RTP fragments to match one frame instead of a fixed guess, so throughput actually tracks frameDurationUs() - a fragment size covering several frames' worth of bytes sent at one-frame timing overruns real-time bandwidth and, over UDP (no flow control), causes packet loss. Returns 0 if not yet known/not applicable (fixed-frame-size codecs have no need to override this).

Reimplemented in ADPCMEncoder, EncoderALAC, AMRNBEncoder, AMRWBEncoder, and MP3ParserEncoder.

mime()

const char * mime ( )

inlinevirtual

Provides the mime type of the encoded result.

Implements AudioEncoder.

operator bool()

virtual operator bool ( )

inlinevirtual

Implements AudioWriter.

samplesPerFrame()

virtual uint16_t samplesPerFrame ( )

inlinevirtualinherited

Optional rtsp function: provide samples per the frame.

Reimplemented in OpusAudioEncoder, OpusMultiStreamAudioEncoder, MP3EncoderShine, MP3ParserEncoder, and MetaDataFilterEncoder.

setAudioInfo() [1/2]

void setAudioInfo ( AudioInfo  from )

inlinevirtual

Defines the Audio Info.

Reimplemented from AudioEncoder.

setAudioInfo() [2/2]

void setAudioInfo ( AudioInfoLAME  from )

inline

Defines the Audio Info.

setOutput()

void setOutput ( Print &  out_stream )

inlinevirtual

Defines the output stream.

Reimplemented from AudioEncoder.

write()

size_t write ( const uint8_t *  data, size_t  len  )

inlinevirtual

Implements AudioWriter.

writeBlocking()

void writeBlocking ( Print *  out, uint8_t *  data, size_t  len  )

inlineprotectedinherited

Member Data Documentation

enc

liblame::MP3EncoderLAME* enc =nullptr

protected

frame_writer

FrameWriter frame_writer {frames}

protected

frames

HeaderParserMP3 frames

protected

info

AudioInfo info

protectedinherited

kMaxFrameSize

constexpr int kMaxFrameSize = 2048

staticconstexprprotected

Buffer size for the frame splitting: bigger than the largest MP3 frame.

lame_info

AudioInfoLAME lame_info

protected

p_print

Print* p_print =nullptr

protected

split_frames

bool split_frames = false

protected

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

• src/AudioTools/AudioCodecs/CodecMP3LAME.h