Packet Lost Concealment (PLC)

Packet lost compensation algorithm. More...

Typedefs
typedef struct pjmedia_plc	pjmedia_plc

Functions
pj_status_t	pjmedia_plc_create (pj_pool_t *pool, unsigned clock_rate, unsigned samples_per_frame, unsigned options, pjmedia_plc **p_plc)
pj_status_t	pjmedia_plc_save (pjmedia_plc *plc, pj_int16_t *frame)
pj_status_t	pjmedia_plc_generate (pjmedia_plc *plc, pj_int16_t *frame)

Detailed Description

This section describes PJMEDIA's implementation of Packet Lost Concealment algorithm. This algorithm is used to implement PLC for codecs that do not have built-in support for one (e.g. G.711 or GSM codecs).

The PLC algorithm (either built-in or external) is embedded in PJMEDIA codec instance, and application can conceal lost frames by calling recover() member of the codec's member operation (pjmedia_codec_op).

See also Concealing Lost Frames for more info.

Typedef Documentation

pjmedia_plc

typedef struct pjmedia_plc pjmedia_plc

Opaque declaration for PLC.

Function Documentation

pjmedia_plc_create()

pj_status_t pjmedia_plc_create	(	pj_pool_t *	pool,
		unsigned	clock_rate,
		unsigned	samples_per_frame,
		unsigned	options,
		pjmedia_plc **	p_plc
	)

Create PLC session. This function will select the PLC algorithm to use based on the arguments.

Parameters

pool	Pool to allocate memory for the PLC.
clock_rate	Media sampling rate.
samples_per_frame	Number of samples per frame.
options	Must be zero for now.
p_plc	Pointer to receive the PLC instance.

Returns

PJ_SUCCESS on success.

pjmedia_plc_save()

pj_status_t pjmedia_plc_save	(	pjmedia_plc *	plc,
		pj_int16_t *	frame
	)

Save a good frame to PLC.

Parameters

plc	The PLC session.
frame	The good frame to be stored to PLC. This frame must have the same length as the configured samples per frame.

Returns

PJ_SUCCESS on success.

pjmedia_plc_generate()

pj_status_t pjmedia_plc_generate	(	pjmedia_plc *	plc,
		pj_int16_t *	frame
	)

Generate a replacement for lost frame.

Parameters

plc	The PLC session.
frame	Buffer to receive the generated frame. This buffer must be able to store the frame.

Returns

PJ_SUCCESS on success.

References PJ_END_DECL.