JitterBuffer: Adaptive jitter buffer

Classes
struct	_JitterBufferPacket
Defines
#define	JITTER_BUFFER_OK   0
#define	JITTER_BUFFER_MISSING   1
#define	JITTER_BUFFER_INCOMPLETE   2
#define	JITTER_BUFFER_INTERNAL_ERROR   -1
#define	JITTER_BUFFER_BAD_ARGUMENT   -2
#define	JITTER_BUFFER_SET_MARGIN   0
#define	JITTER_BUFFER_GET_MARGIN   1
#define	JITTER_BUFFER_GET_AVALIABLE_COUNT   3
#define	JITTER_BUFFER_ADJUST_INTERPOLATE   -1
#define	JITTER_BUFFER_ADJUST_OK   0
#define	JITTER_BUFFER_ADJUST_DROP   1
Typedefs
typedef JitterBuffer_	JitterBuffer
typedef _JitterBufferPacket	JitterBufferPacket
Functions
JitterBuffer *	jitter_buffer_init (int tick)
void	jitter_buffer_reset (JitterBuffer *jitter)
void	jitter_buffer_destroy (JitterBuffer *jitter)
void	jitter_buffer_put (JitterBuffer *jitter, const JitterBufferPacket *packet)
int	jitter_buffer_get (JitterBuffer *jitter, JitterBufferPacket *packet, spx_int32_t *start_offset)
int	jitter_buffer_get_pointer_timestamp (JitterBuffer *jitter)
void	jitter_buffer_tick (JitterBuffer *jitter)
int	jitter_buffer_ctl (JitterBuffer *jitter, int request, void *ptr)
int	jitter_buffer_update_delay (JitterBuffer *jitter, JitterBufferPacket *packet, spx_int32_t *start_offset)

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Detailed Description

This is the jitter buffer that reorders UDP/RTP packets and adjusts the buffer size to maintain good quality and low latency.

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Define Documentation

#define JITTER_BUFFER_BAD_ARGUMENT   -2

Invalid argument

#define JITTER_BUFFER_GET_AVALIABLE_COUNT   3

Get the amount of avaliable packets currently buffered

#define JITTER_BUFFER_GET_MARGIN   1

Get minimum amount of extra buffering required (margin)

#define JITTER_BUFFER_INCOMPLETE   2

Packet is incomplete (does not cover the entive tick

#define JITTER_BUFFER_INTERNAL_ERROR   -1

There was an error in the jitter buffer

#define JITTER_BUFFER_MISSING   1

Packet is missing

#define JITTER_BUFFER_OK   0

Packet has been retrieved

#define JITTER_BUFFER_SET_MARGIN   0

Set minimum amount of extra buffering required (margin)

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Typedef Documentation

typedef struct JitterBuffer_ JitterBuffer

Generic adaptive jitter buffer state

typedef struct _JitterBufferPacket JitterBufferPacket

Definition of an incoming packet

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Function Documentation

int jitter_buffer_ctl	(	JitterBuffer *	jitter,
		int	request,
		void *	ptr
	)

Used like the ioctl function to control the jitter buffer parameters

Parameters:

	jitter	Jitter buffer state
	request	ioctl-type request (one of the JITTER_BUFFER_* macros)
	ptr	Data exchanged to-from function

Returns:

0 if no error, -1 if request in unknown

void jitter_buffer_destroy

(

JitterBuffer *

jitter

)

Destroys jitter buffer

Parameters:

jitter

Jitter buffer state

int jitter_buffer_get	(	JitterBuffer *	jitter,
		JitterBufferPacket *	packet,
		spx_int32_t *	start_offset
	)

Get one packet from the jitter buffer

Parameters:

	jitter	Jitter buffer state
	packet	Returned packet
	current_timestamp	Timestamp for the returned packet

int jitter_buffer_get_pointer_timestamp

(

JitterBuffer *

jitter

)

Get pointer timestamp of jitter buffer

Parameters:

jitter

Jitter buffer state

JitterBuffer* jitter_buffer_init

(

int

tick

)

Initialises jitter buffer

Parameters:

tick

Number of samples per "tick", i.e. the time period of the elements that will be retrieved

Returns:

Newly created jitter buffer state

void jitter_buffer_put	(	JitterBuffer *	jitter,
		const JitterBufferPacket *	packet
	)

Put one packet into the jitter buffer

Parameters:

	jitter	Jitter buffer state
	packet	Incoming packet

void jitter_buffer_reset

(

JitterBuffer *

jitter

)

Restores jitter buffer to its original state

Parameters:

jitter

Jitter buffer state

void jitter_buffer_tick

(

JitterBuffer *

jitter

)

Advance by one tick

Parameters:

jitter

Jitter buffer state

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