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/* $Header: /pjproject-0.3/pjmedia/src/pjmedia/jbuf.h 7 10/14/05 12:23a Bennylp $ */
#ifndef __PJMEDIA_JBUF_H__
#define __PJMEDIA_JBUF_H__
/**
* @file jbuf.h
* @brief Adaptive jitter buffer implementation.
*/
/**
* @defgroup PJMED_JBUF Adaptive jitter buffer
* @ingroup PJMEDIA
* @{
*/
#include <pj/types.h>
PJ_BEGIN_DECL
/**
* Opaque declaration of internal frame type used by jitter buffer.
*/
struct pj_jbframe;
/**
* Miscelaneous operation result/status.
*/
typedef enum jb_op_status
{
PJ_JB_STATUS_TOO_OLD = -2, /** The packet is too old. */
PJ_JB_STATUS_TOO_SOON = -3, /** The packet is too soon. */
PJ_JB_STATUS_FRAME_NULL = -4, /** No packet can be retrieved */
PJ_JB_STATUS_FRAME_MISSING = -5, /** The specified packet is missing/lost */
} jb_op_status;
/*
* Frame list, container abstraction for ordered list with fixed maximum
* size. It is used internally by the jitter buffer.
*/
typedef struct pj_jbframelist
{
unsigned head, count, maxcount;
struct pj_jbframe *frames;
} pj_jbframelist;
/**
* Jitter buffer implementation.
*/
typedef struct pj_jitter_buffer
{
pj_jbframelist lst; /** The frame list. */
int level; /** Current, real-time jitter level. */
int max_level; /** Maximum level for the period. */
unsigned prefetch; /** Prefetch count currently used. */
unsigned get_cnt; /** Number of get operation during prefetch state. */
unsigned min; /** Minimum jitter size, in packets. */
unsigned max; /** Maximum jitter size, in packets. */
pj_uint32_t lastseq; /** Last sequence number put to jitter buffer. */
unsigned upd_count; /** Internal counter to manage update interval. */
int state; /** Jitter buffer state (1==operational) */
int last_op; /** Last jitter buffer operation. */
} pj_jitter_buffer;
/**
* Initialize jitter buffer with the specified parameters.
* This function will allocate internal frame buffer from the specified pool.
* @param jb The jitter buffer to be initialized.
* @param pool Pool where memory will be allocated for the frame buffer.
* @param min The minimum value of jitter buffer, in packets.
* @param max The maximum value of jitter buffer, in packets.
* @param maxcount The maximum number of delay, in packets, which must be
* greater than max.
* @return PJ_SUCCESS on success.
*/
PJ_DECL(pj_status_t) pj_jb_init(pj_jitter_buffer *jb, pj_pool_t *pool,
unsigned min, unsigned max, unsigned maxcount);
/**
* Reset jitter buffer according to the parameters specified when the jitter
* buffer was initialized. Any packets currently in the buffer will be
* discarded.
*/
PJ_DECL(void) pj_jb_reset(pj_jitter_buffer *jb);
/**
* Put a pointer to the buffer with the specified sequence number. The pointer
* normally points to a buffer held by application, and this pointer will be
* returned later on when pj_jb_get() is called. The jitter buffer will not try
* to interpret the content of this pointer.
* @return:
* - PJ_SUCCESS on success.
* - PJ_JB_STATUS_TOO_OLD when the packet is too old.
* - PJ_JB_STATUS_TOO_SOON when the packet is too soon.
*/
PJ_DECL(pj_status_t) pj_jb_put( pj_jitter_buffer *jb, pj_uint32_t extseq, void *buf );
/**
* Get the earliest data from the jitter buffer. ONLY when the operation succeeds,
* the function returns both sequence number and a pointer in the parameters.
* This returned data corresponds to sequence number and pointer that were
* given to jitter buffer in the previous pj_jb_put operation.
* @return
* - PJ_SUCCESS on success
* - PJ_JB_STATUS_FRAME_NULL when there is no frames to be returned.
* - PJ_JB_STATUS_FRAME_MISSING if the jitter buffer detects that the packet
* is lost. Application may run packet concealment algorithm when it
* receives this status.
*/
PJ_DECL(pj_status_t) pj_jb_get( pj_jitter_buffer *jb, pj_uint32_t *extseq, void **buf );
PJ_END_DECL
/**
* @}
*/
#endif /* __PJMEDIA_JBUF_H__ */
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