plc.h File Reference

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Classes
struct	plc_state_t
Defines
#define	_SPANDSP_PLC_H_
#define	PLC_PITCH_MIN   120
#define	PLC_PITCH_MAX   40
#define	PLC_PITCH_OVERLAP_MAX   (PLC_PITCH_MIN >> 2)
#define	CORRELATION_SPAN   160
#define	PLC_HISTORY_LEN   (CORRELATION_SPAN + PLC_PITCH_MIN)
Functions
int	plc_rx (plc_state_t *s, int16_t amp[], int len)
	Process a block of received audio samples for PLC.
int	plc_fillin (plc_state_t *s, int16_t amp[], int len)
	Fill-in a block of missing audio samples.
plc_state_t *	plc_init (plc_state_t *s)
	Initialise a PLC context.
int	plc_release (plc_state_t *s)

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Detailed Description

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Define Documentation

#define CORRELATION_SPAN   160

The length over which the AMDF function looks for similarity (20 ms)

#define PLC_HISTORY_LEN   (CORRELATION_SPAN + PLC_PITCH_MIN)

History buffer length. The buffer much also be at leat 1.25 times PLC_PITCH_MIN, but that is much smaller than the buffer needs to be for the pitch assessment.

#define PLC_PITCH_MAX   40

Maximum allowed pitch (200 Hz)

#define PLC_PITCH_MIN   120

Minimum allowed pitch (66 Hz)

#define PLC_PITCH_OVERLAP_MAX   (PLC_PITCH_MIN >> 2)

Maximum pitch OLA window

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Function Documentation

int plc_fillin (  plc_state_t *  s, int16_t  amp[], int  len )

Fill-in a block of missing audio samples. Fill-in a block of missing audio samples. Parameters: s  The packet loss concealer context. amp  The audio sample buffer. len  The number of samples to be synthesised. Returns: The number of samples synthesized.

plc_state_t* plc_init (  plc_state_t *  s  )

Initialise a PLC context. Initialise a packet loss concealer context. Parameters: s  The packet loss concealer context. Returns: A pointer to the the packet loss concealer context.

int plc_release (  plc_state_t *  s  )

Free a packet loss concealer context. Parameters: s  The packet loss concealer context. Returns: 0 for OK.

int plc_rx (  plc_state_t *  s, int16_t  amp[], int  len )

Process a block of received audio samples for PLC. Process a block of received audio samples for PLC. Parameters: s  The packet loss concealer context. amp  The audio sample buffer. len  The number of samples in the buffer. Returns: The number of samples in the buffer.

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