/* * jitterbuf: an application-independent jitterbuffer * * Copyrights: * Copyright (C) 2004-2005, Horizon Wimba, Inc. * * Contributors: * Steve Kann * Jesse Kaijen (history calc.) * * This program is free software, distributed under the terms of * the GNU Lesser (Library) General Public License * * Copyright on this file is disclaimed to Digium for inclusion in Asterisk */ #ifndef _JITTERBUF_H_ #define _JITTERBUF_H_ #ifdef __cplusplus extern "C" { #endif /* configuration constants */ /* Number of historical timestamps to use in calculating jitter and drift */ #define JB_HISTORY_SZ 250 /* amount of jitterbuffer slack to include */ #define JB_TARGET_EXTRA 0 /* ms between growing and shrinking; may not be honored if jitterbuffer runs out of space */ #define JB_ADJUST_DELAY 40 /* return codes */ #define JB_OK 0 #define JB_EMPTY 1 #define JB_NOFRAME 2 #define JB_INTERP 3 #define JB_DROP 4 /* frame types */ #define JB_TYPE_CONTROL 0 #define JB_TYPE_VOICE 1 #define JB_TYPE_VIDEO 2 /* reserved */ #define JB_TYPE_SILENCE 3 typedef struct jb_info { /* statistics */ long frames_in; /* number of frames input to the jitterbuffer.*/ long frames_out; /* number of frames output from the jitterbuffer.*/ long frames_late; /* number of frames which were too late, and dropped.*/ long frames_lost; /* number of missing frames.*/ long frames_dropped; /* number of frames dropped (shrinkage) */ long frames_ooo; /* number of frames received out-of-order */ long frames_cur; /* number of frames presently in jb, awaiting delivery.*/ long jitter; /* jitter measured within current history interval*/ long min; /* minimum lateness within current history interval */ long current; /* the present jitterbuffer adjustment */ long target; /* the target jitterbuffer adjustment */ long losspct; /* recent lost frame percentage (* 1000) */ long last_voice_ts; /* the last ts that was read from the jb - in receiver's time */ long last_voice_ms; /* the duration of the last voice frame */ long silence_begin_ts; /* the time of the last CNG frame, when in silence */ long last_adjustment; /* the time of the last adjustment */ long cnt_contig_interp; /* the count of consecutive interpolation frames */ /* settings */ long max_jitterbuf; /* defines a hard clamp to use in setting the jitter buffer delay */ long max_contig_interp; /* the max count of interpolations to send before assuming silence */ } jb_info; typedef struct jb_frame { void *data; /* the frame data */ long ts; /* the relative delivery time expected */ long ms; /* the time covered by this frame, in sec/8000 */ int type; /* the type of frame */ struct jb_frame *next, *prev; } jb_frame; typedef struct jitterbuf { jb_info info; /* history */ long history[JB_HISTORY_SZ]; /* history */ long hist_ptr; /* points to index in history for next entry */ long hist_sorted[JB_HISTORY_SZ]; /* a sorted buffer of the delays (lowest first) */ jb_frame *frames; /* queued frames */ jb_frame *free; /* free frames (avoid malloc?) */ } jitterbuf; /* new jitterbuf */ jitterbuf * jb_new(void); /* destroy jitterbuf */ void jb_destroy(jitterbuf *jb); /* reset jitterbuf */ /* NOTE: The jitterbuffer should be empty before you call this, otherwise * you will leak queued frames, and some internal structures */ void jb_reset(jitterbuf *jb); /* queue a frame data=frame data, timings (in ms): ms=length of frame (for voice), ts=ts (sender's time) * now=now (in receiver's time)*/ int jb_put(jitterbuf *jb, void *data, int type, long ms, long ts, long now); /* get a frame for time now (receiver's time) return value is one of * JB_OK: You've got frame! * JB_DROP: Here's an audio frame you should just drop. Ask me again for this time.. * JB_NOFRAME: There's no frame scheduled for this time. * JB_INTERP: Please interpolate an interpl-length frame for this time (either we need to grow, or there was a lost frame * JB_EMPTY: The jb is empty. */ int jb_get(jitterbuf *jb, jb_frame *frame, long now, long interpl); /* unconditionally get frames from jitterbuf until empty */ int jb_getall(jitterbuf *jb, jb_frame *frameout); /* when is the next frame due out, in receiver's time (0=EMPTY) * This value may change as frames are added (esp non-audio frames) */ long jb_next(jitterbuf *jb); /* get jitterbuf info: only "statistics" may be valid */ int jb_getinfo(jitterbuf *jb, jb_info *stats); /* set jitterbuf info: only "settings" may be honored */ int jb_setinfo(jitterbuf *jb, jb_info *settings); typedef void (*jb_output_function_t)(const char *fmt, ...); void jb_setoutput(jb_output_function_t warn, jb_output_function_t err, jb_output_function_t dbg); #ifdef __cplusplus } #endif #endif