frame.h

asterisk 是一个很有知名度开源软件

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2005, Digium, Inc.
 *
 * Mark Spencer <[e-mail]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Asterisk internal frame definitions.
 * \arg For an explanation of frames, see \ref Def_Frame
 * \arg Frames are send of Asterisk channels, see \ref Def_Channel
 */

#ifndef _ASTERISK_FRAME_H
#define _ASTERISK_FRAME_H

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#include <sys/time.h>

#include "asterisk/endian.h"
#include "asterisk/linkedlists.h"

struct ast_codec_pref {
	char order[32];
	char framing[32];
};

/*! \page Def_Frame AST Multimedia and signalling frames
	\section Def_AstFrame What is an ast_frame ?
 	A frame of data read used to communicate between 
 	between channels and applications.
	Frames are divided into frame types and subclasses.

	\par Frame types 
	\arg \b VOICE:	Voice data, subclass is codec (AST_FORMAT_*)
	\arg \b VIDEO:	Video data, subclass is codec (AST_FORMAT_*)
	\arg \b DTMF:	A DTMF digit, subclass is the digit
	\arg \b IMAGE:	Image transport, mostly used in IAX
	\arg \b TEXT:	Text messages and character by character (real time text)
	\arg \b HTML:	URL's and web pages
	\arg \b MODEM:	Modulated data encodings, such as T.38 and V.150
	\arg \b IAX:	Private frame type for the IAX protocol
	\arg \b CNG:	Comfort noice frames
	\arg \b CONTROL:	A control frame, subclass defined as AST_CONTROL_
	\arg \b NULL:	Empty, useless frame

	\par Files
	\arg frame.h	Definitions
	\arg frame.c	Function library
	\arg \ref Def_Channel Asterisk channels
	\section Def_ControlFrame Control Frames
	Control frames send signalling information between channels
	and devices. They are prefixed with AST_CONTROL_, like AST_CONTROL_FRAME_HANGUP
	\arg \b HANGUP	The other end has hungup
	\arg \b RING	Local ring
	\arg \b RINGING	The other end is ringing
	\arg \b ANSWER	The other end has answered
	\arg \b BUSY	Remote end is busy
	\arg \b TAKEOFFHOOK	Make it go off hook (what's "it" ? )
	\arg \b OFFHOOK	Line is off hook
	\arg \b CONGESTION	Congestion (circuit is busy, not available)
	\arg \b FLASH	Other end sends flash hook
	\arg \b WINK	Other end sends wink
	\arg \b OPTION	Send low-level option
	\arg \b RADIO_KEY	Key radio (see app_rpt.c)
	\arg \b RADIO_UNKEY	Un-key radio (see app_rpt.c)
	\arg \b PROGRESS	Other end indicates call progress
	\arg \b PROCEEDING	Indicates proceeding
	\arg \b HOLD	Call is placed on hold
	\arg \b UNHOLD	Call is back from hold
	\arg \b VIDUPDATE	Video update requested
	\arg \b SRCUPDATE       The source of media has changed

*/

/*!
 * \brief Frame types 
 *
 * \note It is important that the values of each frame type are never changed,
 *       because it will break backwards compatability with older versions.
 *       This is because these constants are transmitted directly over IAX2.
 */
enum ast_frame_type {
	/*! DTMF end event, subclass is the digit */
	AST_FRAME_DTMF_END = 1,
	/*! Voice data, subclass is AST_FORMAT_* */
	AST_FRAME_VOICE,
	/*! Video frame, maybe?? :) */
	AST_FRAME_VIDEO,
	/*! A control frame, subclass is AST_CONTROL_* */
	AST_FRAME_CONTROL,
	/*! An empty, useless frame */
	AST_FRAME_NULL,
	/*! Inter Asterisk Exchange private frame type */
	AST_FRAME_IAX,
	/*! Text messages */
	AST_FRAME_TEXT,
	/*! Image Frames */
	AST_FRAME_IMAGE,
	/*! HTML Frame */
	AST_FRAME_HTML,
	/*! Comfort Noise frame (subclass is level of CNG in -dBov), 
	    body may include zero or more 8-bit quantization coefficients */
	AST_FRAME_CNG,
	/*! Modem-over-IP data streams */
	AST_FRAME_MODEM,	
	/*! DTMF begin event, subclass is the digit */
	AST_FRAME_DTMF_BEGIN,
};
#define AST_FRAME_DTMF AST_FRAME_DTMF_END

enum {
	/*! This frame contains valid timing information */
	AST_FRFLAG_HAS_TIMING_INFO = (1 << 0),
	/*! This frame came from a translator and is still the original frame.
	 *  The translator can not be free'd if the frame inside of it still has
	 *  this flag set. */
	AST_FRFLAG_FROM_TRANSLATOR = (1 << 1),
	/*! This frame came from a dsp and is still the original frame.
	 *  The dsp cannot be free'd if the frame inside of it still has
	 *  this flag set. */
	AST_FRFLAG_FROM_DSP = (1 << 2),
	/*! This frame came from a filestream and is still the original frame.
	 *  The filestream cannot be free'd if the frame inside of it still has
	 *  this flag set. */
	AST_FRFLAG_FROM_FILESTREAM = (1 << 3),
};

/*! \brief Data structure associated with a single frame of data
 */
struct ast_frame {
	/*! Kind of frame */
	enum ast_frame_type frametype;				
	/*! Subclass, frame dependent */
	int subclass;				
	/*! Length of data */
	int datalen;				
	/*! Number of 8khz samples in this frame */
	int samples;				
	/*! Was the data malloc'd?  i.e. should we free it when we discard the frame? */
	int mallocd;				
	/*! The number of bytes allocated for a malloc'd frame header */
	size_t mallocd_hdr_len;
	/*! How many bytes exist _before_ "data" that can be used if needed */
	int offset;				
	/*! Optional source of frame for debugging */
	const char *src;				
	/*! Pointer to actual data */
	void *data;		
	/*! Global delivery time */		
	struct timeval delivery;
	/*! For placing in a linked list */
	AST_LIST_ENTRY(ast_frame) frame_list;
	/*! Misc. frame flags */
	unsigned int flags;
	/*! Timestamp in milliseconds */
	long ts;
	/*! Length in milliseconds */
	long len;
	/*! Sequence number */
	int seqno;
};

/*!
 * Set the various field of a frame to point to a buffer.
 * Typically you set the base address of the buffer, the offset as
 * AST_FRIENDLY_OFFSET, and the datalen as the amount of bytes queued.
 * The remaining things (to be done manually) is set the number of
 * samples, which cannot be derived from the datalen unless you know
 * the number of bits per sample.
 */
#define	AST_FRAME_SET_BUFFER(fr, _base, _ofs, _datalen)	\
	{					\
	(fr)->data = (char *)_base + (_ofs);	\
	(fr)->offset = (_ofs);			\
	(fr)->datalen = (_datalen);		\
	}

/*! Queueing a null frame is fairly common, so we declare a global null frame object
    for this purpose instead of having to declare one on the stack */
extern struct ast_frame ast_null_frame;

#define AST_FRIENDLY_OFFSET 	64	/*! It's polite for a a new frame to
					  have this number of bytes for additional
					  headers.  */
#define AST_MIN_OFFSET 		32	/*! Make sure we keep at least this much handy */

/*! Need the header be free'd? */
#define AST_MALLOCD_HDR		(1 << 0)
/*! Need the data be free'd? */
#define AST_MALLOCD_DATA	(1 << 1)
/*! Need the source be free'd? (haha!) */
#define AST_MALLOCD_SRC		(1 << 2)

/* MODEM subclasses */
/*! T.38 Fax-over-IP */
#define AST_MODEM_T38		1
/*! V.150 Modem-over-IP */
#define AST_MODEM_V150		2

/* HTML subclasses */
/*! Sending a URL */
#define AST_HTML_URL		1
/*! Data frame */
#define AST_HTML_DATA		2
/*! Beginning frame */
#define AST_HTML_BEGIN		4
/*! End frame */
#define AST_HTML_END		8
/*! Load is complete */
#define AST_HTML_LDCOMPLETE	16
/*! Peer is unable to support HTML */
#define AST_HTML_NOSUPPORT	17
/*! Send URL, and track */
#define AST_HTML_LINKURL	18
/*! No more HTML linkage */
#define AST_HTML_UNLINK		19
/*! Reject link request */
#define AST_HTML_LINKREJECT	20

/* Data formats for capabilities and frames alike */
/*! G.723.1 compression */
#define AST_FORMAT_G723_1	(1 << 0)
/*! GSM compression */
#define AST_FORMAT_GSM		(1 << 1)
/*! Raw mu-law data (G.711) */
#define AST_FORMAT_ULAW		(1 << 2)
/*! Raw A-law data (G.711) */
#define AST_FORMAT_ALAW		(1 << 3)
/*! ADPCM (G.726, 32kbps, AAL2 codeword packing) */
#define AST_FORMAT_G726_AAL2	(1 << 4)
/*! ADPCM (IMA) */
#define AST_FORMAT_ADPCM	(1 << 5)
/*! Raw 16-bit Signed Linear (8000 Hz) PCM */
#define AST_FORMAT_SLINEAR	(1 << 6)
/*! LPC10, 180 samples/frame */
#define AST_FORMAT_LPC10	(1 << 7)
/*! G.729A audio */
#define AST_FORMAT_G729A	(1 << 8)
/*! SpeeX Free Compression */
#define AST_FORMAT_SPEEX	(1 << 9)
/*! iLBC Free Compression */
#define AST_FORMAT_ILBC		(1 << 10)
/*! ADPCM (G.726, 32kbps, RFC3551 codeword packing) */
#define AST_FORMAT_G726		(1 << 11)
/*! G.722 */
#define AST_FORMAT_G722		(1 << 12)
/*! Raw 16-bit Signed Linear (16000 Hz) PCM */
#define AST_FORMAT_SLINEAR16	(1 << 15)
/*! Maximum audio mask */
#define AST_FORMAT_AUDIO_MASK   ((1 << 16)-1)
/*! JPEG Images */
#define AST_FORMAT_JPEG		(1 << 16)
/*! PNG Images */
#define AST_FORMAT_PNG		(1 << 17)
/*! H.261 Video */
#define AST_FORMAT_H261		(1 << 18)
/*! H.263 Video */
#define AST_FORMAT_H263		(1 << 19)
/*! H.263+ Video */
#define AST_FORMAT_H263_PLUS	(1 << 20)
/*! H.264 Video */
#define AST_FORMAT_H264		(1 << 21)
/*! MPEG4 Video */
#define AST_FORMAT_MP4_VIDEO	(1 << 22)
#define AST_FORMAT_VIDEO_MASK   (((1 << 25)-1) & ~(AST_FORMAT_AUDIO_MASK))
/*! T.140 Text format - ITU T.140, RFC 4351*/
#define AST_FORMAT_T140		(1 << 25)
#define AST_FORMAT_TEXT_MASK   (((1 << 30)-1) & ~(AST_FORMAT_AUDIO_MASK) & ~(AST_FORMAT_VIDEO_MASK))

enum ast_control_frame_type {
	AST_CONTROL_HANGUP = 1,		/*!< Other end has hungup */
	AST_CONTROL_RING = 2,		/*!< Local ring */
	AST_CONTROL_RINGING = 3,	/*!< Remote end is ringing */
	AST_CONTROL_ANSWER = 4,		/*!< Remote end has answered */
	AST_CONTROL_BUSY = 5,		/*!< Remote end is busy */
	AST_CONTROL_TAKEOFFHOOK = 6,	/*!< Make it go off hook */
	AST_CONTROL_OFFHOOK = 7,	/*!< Line is off hook */
	AST_CONTROL_CONGESTION = 8,	/*!< Congestion (circuits busy) */
	AST_CONTROL_FLASH = 9,		/*!< Flash hook */
	AST_CONTROL_WINK = 10,		/*!< Wink */
	AST_CONTROL_OPTION = 11,	/*!< Set a low-level option */
	AST_CONTROL_RADIO_KEY = 12,	/*!< Key Radio */
	AST_CONTROL_RADIO_UNKEY = 13,	/*!< Un-Key Radio */
	AST_CONTROL_PROGRESS = 14,	/*!< Indicate PROGRESS */
	AST_CONTROL_PROCEEDING = 15,	/*!< Indicate CALL PROCEEDING */
	AST_CONTROL_HOLD = 16,		/*!< Indicate call is placed on hold */
	AST_CONTROL_UNHOLD = 17,	/*!< Indicate call is left from hold */
	AST_CONTROL_VIDUPDATE = 18,	/*!< Indicate video frame update */
	AST_CONTROL_T38 = 19,		/*!< T38 state change request/notification */
	AST_CONTROL_SRCUPDATE = 20,     /*!< Indicate source of media has changed */
};

enum ast_control_t38 {
	AST_T38_REQUEST_NEGOTIATE = 1,	/*!< Request T38 on a channel (voice to fax) */
	AST_T38_REQUEST_TERMINATE,	/*!< Terminate T38 on a channel (fax to voice) */
	AST_T38_NEGOTIATED,		/*!< T38 negotiated (fax mode) */
	AST_T38_TERMINATED,		/*!< T38 terminated (back to voice) */
	AST_T38_REFUSED			/*!< T38 refused for some reason (usually rejected by remote end) */
};

#define AST_SMOOTHER_FLAG_G729		(1 << 0)
#define AST_SMOOTHER_FLAG_BE		(1 << 1)

/* Option identifiers and flags */
#define AST_OPTION_FLAG_REQUEST		0