Class for decoding of incoming RTP, resampling it to target sample rate and slicing to frames of target size. More...

#include <MpJitterBuffer.h>

Collaboration diagram for MpJitterBuffer:

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Public Member Functions
Creators
	MpJitterBuffer (MpDecoderPayloadMap *pPayloadMap=NULL, const UtlString &resourceName="unknown")
	Constructor. More...

void	init (unsigned int samplesPerSec, unsigned int samplesPerFrame)
	Initialize with given sample rate and frame size. More...

	~MpJitterBuffer ()
	Destructor. More...

Manipulators
void	reset ()
	Reset class to the initial state, preparing for handling new stream. More...

OsStatus	pushPacket (const MpRtpBufPtr &rtpPacket, int minBufferSamples, int wantedBufferSamples, int &decodedSamples, int &adjustment, UtlBoolean &played)
	Push packet into decoder buffer. More...

void	getFrame (MpAudioBufPtr &pFrame, int &numOriginalSamples)
	Get next frame from decoder buffer. More...

void	setCodecList (MpDecoderPayloadMap *pPayloadMap)
	Update list of available decoders. More...

void	setPlc (const UtlString &plcName)
	Change PLC algorithm to one provided. More...

Accessors
void	setFlowGraph (MpFlowGraphBase *pFlowgraph)
	Set the pointer to the parent flowgraph for debug purposes. More...

int	getSamplesNum () const
	Get number of samples, remaining in buffer. More...

OsStatus	setVadParam (const UtlString &name, int value)
	Set parameter on the VAD component. More...

Protected Member Functions
int	adjustStream (MpAudioSample *pBuffer, int bufferSize, unsigned numSamples, int wantedAdjustment)
	Reduce or extend audio fragment. More...

OsStatus	sliceToFrames (int decodedSamples, int codecSampleRate, const MpSpeechParams &speechParams)

Private Types
enum	{ FRAMES_TO_STORE = 32, DECODED_DATA_MAX_LENGTH = 10 * 160 }

Private Member Functions
	MpJitterBuffer (const MpJitterBuffer &rMpJitterBuffer)
	Copy constructor. More...

MpJitterBuffer &	operator= (const MpJitterBuffer &rhs)
	Assignment operator. More...

Private Attributes
UtlString	mPlcName
	Packet Loss Concealer algorithm name. More...

MpPlcBase *	mpPlc
	Packet Loss Concealer instance. More...

MpVadBase *	mpVad
	Voice Activity Detector instance. More...

MpAgcBase *	mpAgc
	Automatic Gain Calculator instance. More...

MpFlowGraphBase *	mpFlowGraph
	Parent flowgraph for debugging. More...

Resampler variables.
int	mStreamSampleRate
	Sample rate of incoming RTP stream. More...

int	mOutputSampleRate

int	mSamplesPerFrame
	Number of samples to put to output buffers. More...

MpAudioSample	mDecodedData [DECODED_DATA_MAX_LENGTH]
	temporarily store decoded data. More...

MpResamplerBase *	mpResampler

Audio buffers variables.
unsigned	mCurFrameNum

unsigned	mRemainingSamplesNum

MpAudioBufPtr	mFrames [FRAMES_TO_STORE]
	Buffer for decoded, resampled and sliced audio. More...

int	mOriginalSamples [FRAMES_TO_STORE]
	before resampling was done. More...

Decoding related variables.
UtlBoolean	mIsFirstPacket
	Have we received our first packet or not. More...

RtpSeq	mStreamSeq
	Sequence number of last played RTP packet. More...

RtpTimestamp	mStreamTimestamp
	Timestamp of last played RTP packet. More...

uint8_t	mStreamRtpPayload
	Payload type of last received RTP packet. More...

MpDecoderPayloadMap *	mpPayloadMap

unsigned	mSamplesPerPacket
	Number of samples in RTP packet. More...

Detailed Description

Class for decoding of incoming RTP, resampling it to target sample rate and slicing to frames of target size.

This class is not thread-safe. For thread-safety it relies on external synchronization mechanisms in MprDecode.

Member Enumeration Documentation

anonymous enum

private

Enumerator
FRAMES_TO_STORE	Number of frames to store in buffer. Should be a power of 2.
DECODED_DATA_MAX_LENGTH	Size of mDecodedData temporary buffer.

Constructor & Destructor Documentation

MpJitterBuffer	(	MpDecoderPayloadMap *	pPayloadMap = `NULL`,
		const UtlString &	resourceName = `"unknown"`
	)

Constructor.

Parameters

[in]	pPayloadMap	- set of decoders, mapped to their RTP payload types.
[in]	resourceName	- name of the resource that this is part of. Used for debugging and logging purposes.

~MpJitterBuffer ( )

Destructor.

MpJitterBuffer ( const MpJitterBuffer & rMpJitterBuffer )

private

Copy constructor.

Member Function Documentation

void init	(	unsigned int	samplesPerSec,
		unsigned int	samplesPerFrame
	)

Initialize with given sample rate and frame size.

Should be called only once upon construction of an object.

void reset ( )

Reset class to the initial state, preparing for handling new stream.

OsStatus pushPacket	(	const MpRtpBufPtr &	rtpPacket,
		int	minBufferSamples,
		int	wantedBufferSamples,
		int &	decodedSamples,
		int &	adjustment,
		UtlBoolean &	played
	)

Push packet into decoder buffer.

Packet will be decoded and decoded data will be copied to internal buffer. If no decoder is available for this packet's payload type packet will be ignored.

Parameters

[in]	rtpPacket	- RTP packet to be decoded.
[in]	minBufferSamples	- minimum number of samples to remain in buffer after decoding and applying adjustment. This is useful, when we do not want to decode more packets at this moment, but need a frame of audio for processing.
[in]	wantedBufferSamples	- number of samples we want to have in buffer after decoding packet. Note, this value may be negative - this means we want to shorten our buffer as much as possible.
[out]	decodedSamples	- number of samples, decoded from packet.
[out]	adjustment	- how many samples were added or removed from stream to fulfil `wantedBufferSamples` request.
[out]	played	- was passed RTP packet decoded and added to decoder buffer, or it was dropped or used just to update PLC history. I.e. if `played=FALSE` then number of samples in buffer was not increased.

Note: This implementation behave unpredictable if packets come reordered.; Valid RTP packet MUST be passed with first call to this function.

Return values

OS_SUCCESS	if RTP packet was successfully decoded.
OS_FAILED	in case of any problems.

void getFrame	(	MpAudioBufPtr &	pFrame,
		int &	numOriginalSamples
	)

Get next frame from decoder buffer.

Note: pFrame must be NULL before passing to this method!

Parameters

[out]	pFrame	- pointer to returned frame.
[out]	numOriginalSamples	- number of samples in returned frame would be without resampling.

void setCodecList ( MpDecoderPayloadMap * pPayloadMap )

Update list of available decoders.

void setPlc ( const UtlString & plcName )

Change PLC algorithm to one provided.

void setFlowGraph ( MpFlowGraphBase * pFlowgraph )

Set the pointer to the parent flowgraph for debug purposes.

int getSamplesNum ( ) const

inline

Get number of samples, remaining in buffer.

OsStatus setVadParam	(	const UtlString &	name,
		int	value
	)

Set parameter on the VAD component.

int adjustStream	(	MpAudioSample *	pBuffer,
		int	bufferSize,
		unsigned	numSamples,
		int	wantedAdjustment
	)

protected

Reduce or extend audio fragment.

OsStatus sliceToFrames	(	int	decodedSamples,
		int	codecSampleRate,
		const MpSpeechParams &	speechParams
	)

protected

MpJitterBuffer& operator= ( const MpJitterBuffer & rhs )

private

Assignment operator.

Member Data Documentation

int mStreamSampleRate

private

Sample rate of incoming RTP stream.

int mOutputSampleRate

private

Output sample rate for decoded data. Samples from codecs with different sample rates will be resampled to this sample rate.

int mSamplesPerFrame

private

Number of samples to put to output buffers.

MpAudioSample mDecodedData[DECODED_DATA_MAX_LENGTH]

private

temporarily store decoded data.

Buffer, used to

MpResamplerBase* mpResampler

private

Resampler instance to convert codec sample rate to flowgraph sample rate.

unsigned mCurFrameNum

private

Internal sequence number of oldest frame in mFrames[]. It is also used as a base for frames index calculation.

unsigned mRemainingSamplesNum

private

Total number of samples still residing in mFrames[].

MpAudioBufPtr mFrames[FRAMES_TO_STORE]

private

Buffer for decoded, resampled and sliced audio.

int mOriginalSamples[FRAMES_TO_STORE]

private

before resampling was done.

Numbers of samples in frames

UtlBoolean mIsFirstPacket

private

Have we received our first packet or not.

RtpSeq mStreamSeq

private

Sequence number of last played RTP packet.

RtpTimestamp mStreamTimestamp

private

Timestamp of last played RTP packet.

uint8_t mStreamRtpPayload

private

Payload type of last received RTP packet.

MpDecoderPayloadMap* mpPayloadMap

private

Map of RTP payload types to decoders. Note, we do not own instance of this map, we only store pointer to it.

unsigned mSamplesPerPacket

private

Number of samples in RTP packet.

UtlString mPlcName

private

Packet Loss Concealer algorithm name.

MpPlcBase* mpPlc

private

Packet Loss Concealer instance.

MpVadBase* mpVad

private

Voice Activity Detector instance.

MpAgcBase* mpAgc

private

Automatic Gain Calculator instance.

MpFlowGraphBase* mpFlowGraph

private

Parent flowgraph for debugging.

Public Member Functions

Protected Member Functions

Private Types

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation