2 * Asterisk -- An open source telephony toolkit.
4 * Copyright (C) 1999 - 2005, Digium, Inc.
6 * Mark Spencer <markster@digium.com>
8 * See http://www.asterisk.org for more information about
9 * the Asterisk project. Please do not directly contact
10 * any of the maintainers of this project for assistance;
11 * the project provides a web site, mailing lists and IRC
12 * channels for your use.
14 * This program is free software, distributed under the terms of
15 * the GNU General Public License Version 2. See the LICENSE file
16 * at the top of the source tree.
20 * \brief Asterisk internal frame definitions.
21 * \arg For an explanation of frames, see \ref Def_Frame
22 * \arg Frames are send of Asterisk channels, see \ref Def_Channel
25 #ifndef _ASTERISK_FRAME_H
26 #define _ASTERISK_FRAME_H
28 #if defined(__cplusplus) || defined(c_plusplus)
34 #include "asterisk/format.h"
35 #include "asterisk/endian.h"
36 #include "asterisk/linkedlists.h"
39 * \page Def_Frame AST Multimedia and signalling frames
40 * \section Def_AstFrame What is an ast_frame ?
41 * A frame of data read used to communicate between
42 * between channels and applications.
43 * Frames are divided into frame types and subclasses.
46 * \arg \b VOICE: Voice data, subclass is codec (AST_FORMAT_*)
47 * \arg \b VIDEO: Video data, subclass is codec (AST_FORMAT_*)
48 * \arg \b DTMF: A DTMF digit, subclass is the digit
49 * \arg \b IMAGE: Image transport, mostly used in IAX
50 * \arg \b TEXT: Text messages and character by character (real time text)
51 * \arg \b HTML: URL's and web pages
52 * \arg \b MODEM: Modulated data encodings, such as T.38 and V.150
53 * \arg \b IAX: Private frame type for the IAX protocol
54 * \arg \b CNG: Comfort noice frames
55 * \arg \b CONTROL:A control frame, subclass defined as AST_CONTROL_
56 * \arg \b NULL: Empty, useless frame
59 * \arg frame.h Definitions
60 * \arg frame.c Function library
61 * \arg \ref Def_Channel Asterisk channels
62 * \section Def_ControlFrame Control Frames
63 * Control frames send signalling information between channels
64 * and devices. They are prefixed with AST_CONTROL_, like AST_CONTROL_FRAME_HANGUP
65 * \arg \b HANGUP The other end has hungup
66 * \arg \b RING Local ring
67 * \arg \b RINGING The other end is ringing
68 * \arg \b ANSWER The other end has answered
69 * \arg \b BUSY Remote end is busy
70 * \arg \b TAKEOFFHOOK Make it go off hook (what's "it" ? )
71 * \arg \b OFFHOOK Line is off hook
72 * \arg \b CONGESTION Congestion (circuit is busy, not available)
73 * \arg \b FLASH Other end sends flash hook
74 * \arg \b WINK Other end sends wink
75 * \arg \b OPTION Send low-level option
76 * \arg \b RADIO_KEY Key radio (see app_rpt.c)
77 * \arg \b RADIO_UNKEY Un-key radio (see app_rpt.c)
78 * \arg \b PROGRESS Other end indicates call progress
79 * \arg \b PROCEEDING Indicates proceeding
80 * \arg \b HOLD Call is placed on hold
81 * \arg \b UNHOLD Call is back from hold
82 * \arg \b VIDUPDATE Video update requested
83 * \arg \b SRCUPDATE The source of media has changed (RTP marker bit must change)
84 * \arg \b SRCCHANGE Media source has changed (RTP marker bit and SSRC must change)
85 * \arg \b CONNECTED_LINE Connected line has changed
86 * \arg \b REDIRECTING Call redirecting information has changed.
92 * \note It is important that the values of each frame type are never changed,
93 * because it will break backwards compatability with older versions.
94 * This is because these constants are transmitted directly over IAX2.
97 /*! DTMF end event, subclass is the digit */
98 AST_FRAME_DTMF_END = 1,
99 /*! Voice data, subclass is AST_FORMAT_* */
101 /*! Video frame, maybe?? :) */
103 /*! A control frame, subclass is AST_CONTROL_* */
105 /*! An empty, useless frame */
107 /*! Inter Asterisk Exchange private frame type */
115 /*! Comfort Noise frame (subclass is level of CNG in -dBov),
116 body may include zero or more 8-bit quantization coefficients */
118 /*! Modem-over-IP data streams */
120 /*! DTMF begin event, subclass is the digit */
121 AST_FRAME_DTMF_BEGIN,
122 /*! Internal bridge module action. */
123 AST_FRAME_BRIDGE_ACTION,
124 /*! Internal synchronous bridge module action.
125 * Synchronous bridge actions may be queued onto bridge
126 * channels, but they absolutely must not ever be written
127 * directly into bridges.
129 AST_FRAME_BRIDGE_ACTION_SYNC,
131 #define AST_FRAME_DTMF AST_FRAME_DTMF_END
134 /*! This frame contains valid timing information */
135 AST_FRFLAG_HAS_TIMING_INFO = (1 << 0),
136 /*! This frame has been requeued */
137 AST_FRFLAG_REQUEUED = (1 << 1),
140 struct ast_frame_subclass {
141 /*! A frame specific code */
143 /*! The asterisk media format */
144 struct ast_format *format;
145 /*! For video formats, an indication that a frame ended */
146 unsigned int frame_ending;
149 /*! \brief Data structure associated with a single frame of data
153 enum ast_frame_type frametype;
154 /*! Subclass, frame dependent */
155 struct ast_frame_subclass subclass;
156 /*! Length of data */
158 /*! Number of samples in this frame */
160 /*! Was the data malloc'd? i.e. should we free it when we discard the frame? */
162 /*! The number of bytes allocated for a malloc'd frame header */
163 size_t mallocd_hdr_len;
164 /*! How many bytes exist _before_ "data" that can be used if needed */
166 /*! Optional source of frame for debugging */
168 /*! Pointer to actual data */
169 union { void *ptr; uint32_t uint32; char pad[8]; } data;
170 /*! Global delivery time */
171 struct timeval delivery;
172 /*! For placing in a linked list */
173 AST_LIST_ENTRY(ast_frame) frame_list;
174 /*! Misc. frame flags */
176 /*! Timestamp in milliseconds */
178 /*! Length in milliseconds */
180 /*! Sequence number */
185 * Set the various field of a frame to point to a buffer.
186 * Typically you set the base address of the buffer, the offset as
187 * AST_FRIENDLY_OFFSET, and the datalen as the amount of bytes queued.
188 * The remaining things (to be done manually) is set the number of
189 * samples, which cannot be derived from the datalen unless you know
190 * the number of bits per sample.
192 #define AST_FRAME_SET_BUFFER(fr, _base, _ofs, _datalen) \
194 (fr)->data.ptr = (char *)_base + (_ofs); \
195 (fr)->offset = (_ofs); \
196 (fr)->datalen = (_datalen); \
199 /*! Queueing a null frame is fairly common, so we declare a global null frame object
200 for this purpose instead of having to declare one on the stack */
201 extern struct ast_frame ast_null_frame;
203 /*! \brief Offset into a frame's data buffer.
205 * By providing some "empty" space prior to the actual data of an ast_frame,
206 * this gives any consumer of the frame ample space to prepend other necessary
207 * information without having to create a new buffer.
209 * As an example, RTP can use the data from an ast_frame and simply prepend the
210 * RTP header information into the space provided by AST_FRIENDLY_OFFSET instead
211 * of having to create a new buffer with the necessary space allocated.
213 #define AST_FRIENDLY_OFFSET 64
214 #define AST_MIN_OFFSET 32 /*! Make sure we keep at least this much handy */
216 /*! Need the header be free'd? */
217 #define AST_MALLOCD_HDR (1 << 0)
218 /*! Need the data be free'd? */
219 #define AST_MALLOCD_DATA (1 << 1)
220 /*! Need the source be free'd? (haha!) */
221 #define AST_MALLOCD_SRC (1 << 2)
223 /* MODEM subclasses */
224 /*! T.38 Fax-over-IP */
225 #define AST_MODEM_T38 1
226 /*! V.150 Modem-over-IP */
227 #define AST_MODEM_V150 2
229 /* HTML subclasses */
231 #define AST_HTML_URL 1
233 #define AST_HTML_DATA 2
234 /*! Beginning frame */
235 #define AST_HTML_BEGIN 4
237 #define AST_HTML_END 8
238 /*! Load is complete */
239 #define AST_HTML_LDCOMPLETE 16
240 /*! Peer is unable to support HTML */
241 #define AST_HTML_NOSUPPORT 17
242 /*! Send URL, and track */
243 #define AST_HTML_LINKURL 18
244 /*! No more HTML linkage */
245 #define AST_HTML_UNLINK 19
246 /*! Reject link request */
247 #define AST_HTML_LINKREJECT 20
250 * \brief Internal control frame subtype field values.
253 * IAX2 sends these values out over the wire. To prevent future
254 * incompatibilities, pick the next value in the enum from whatever
255 * is on the current trunk. If you lose the merge race you need to
256 * fix the previous branches to match what is on trunk. In addition
257 * you need to change chan_iax2 to explicitly allow the control
258 * frame over the wire if it makes sense for the frame to be passed
259 * to another Asterisk instance.
261 enum ast_control_frame_type {
262 AST_CONTROL_HANGUP = 1, /*!< Other end has hungup */
263 AST_CONTROL_RING = 2, /*!< Local ring */
264 AST_CONTROL_RINGING = 3, /*!< Remote end is ringing */
265 AST_CONTROL_ANSWER = 4, /*!< Remote end has answered */
266 AST_CONTROL_BUSY = 5, /*!< Remote end is busy */
267 AST_CONTROL_TAKEOFFHOOK = 6, /*!< Make it go off hook */
268 AST_CONTROL_OFFHOOK = 7, /*!< Line is off hook */
269 AST_CONTROL_CONGESTION = 8, /*!< Congestion (circuits busy) */
270 AST_CONTROL_FLASH = 9, /*!< Flash hook */
271 AST_CONTROL_WINK = 10, /*!< Wink */
272 AST_CONTROL_OPTION = 11, /*!< Set a low-level option */
273 AST_CONTROL_RADIO_KEY = 12, /*!< Key Radio */
274 AST_CONTROL_RADIO_UNKEY = 13, /*!< Un-Key Radio */
275 AST_CONTROL_PROGRESS = 14, /*!< Indicate PROGRESS */
276 AST_CONTROL_PROCEEDING = 15, /*!< Indicate CALL PROCEEDING */
277 AST_CONTROL_HOLD = 16, /*!< Indicate call is placed on hold */
278 AST_CONTROL_UNHOLD = 17, /*!< Indicate call is left from hold */
279 AST_CONTROL_VIDUPDATE = 18, /*!< Indicate video frame update */
280 _XXX_AST_CONTROL_T38 = 19, /*!< T38 state change request/notification \deprecated This is no longer supported. Use AST_CONTROL_T38_PARAMETERS instead. */
281 AST_CONTROL_SRCUPDATE = 20, /*!< Indicate source of media has changed */
282 AST_CONTROL_TRANSFER = 21, /*!< Indicate status of a transfer request */
283 AST_CONTROL_CONNECTED_LINE = 22,/*!< Indicate connected line has changed */
284 AST_CONTROL_REDIRECTING = 23, /*!< Indicate redirecting id has changed */
285 AST_CONTROL_T38_PARAMETERS = 24,/*!< T38 state change request/notification with parameters */
286 AST_CONTROL_CC = 25, /*!< Indication that Call completion service is possible */
287 AST_CONTROL_SRCCHANGE = 26, /*!< Media source has changed and requires a new RTP SSRC */
288 AST_CONTROL_READ_ACTION = 27, /*!< Tell ast_read to take a specific action */
289 AST_CONTROL_AOC = 28, /*!< Advice of Charge with encoded generic AOC payload */
290 AST_CONTROL_END_OF_Q = 29, /*!< Indicate that this position was the end of the channel queue for a softhangup. */
291 AST_CONTROL_INCOMPLETE = 30, /*!< Indication that the extension dialed is incomplete */
292 AST_CONTROL_MCID = 31, /*!< Indicate that the caller is being malicious. */
293 AST_CONTROL_UPDATE_RTP_PEER = 32, /*!< Interrupt the bridge and have it update the peer */
294 AST_CONTROL_PVT_CAUSE_CODE = 33, /*!< Contains an update to the protocol-specific cause-code stored for branching dials */
295 AST_CONTROL_MASQUERADE_NOTIFY = 34, /*!< A masquerade is about to begin/end. (Never sent as a frame but directly with ast_indicate_data().) */
298 * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
300 * IAX2 sends these values out over the wire. To prevent future
301 * incompatibilities, pick the next value in the enum from whatever
302 * is on the current trunk. If you lose the merge race you need to
303 * fix the previous branches to match what is on trunk. In addition
304 * you need to change chan_iax2 to explicitly allow the control
305 * frame over the wire if it makes sense for the frame to be passed
306 * to another Asterisk instance.
308 * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
311 /* Control frames used to manipulate a stream on a channel. The values for these
312 * must be greater than the allowed value for a 8-bit char, so that they avoid
313 * conflicts with DTMF values. */
314 AST_CONTROL_STREAM_STOP = 1000, /*!< Indicate to a channel in playback to stop the stream */
315 AST_CONTROL_STREAM_SUSPEND = 1001, /*!< Indicate to a channel in playback to suspend the stream */
316 AST_CONTROL_STREAM_RESTART = 1002, /*!< Indicate to a channel in playback to restart the stream */
317 AST_CONTROL_STREAM_REVERSE = 1003, /*!< Indicate to a channel in playback to rewind */
318 AST_CONTROL_STREAM_FORWARD = 1004, /*!< Indicate to a channel in playback to fast forward */
319 /* Control frames to manipulate recording on a channel. */
320 AST_CONTROL_RECORD_CANCEL = 1100, /*!< Indicated to a channel in record to stop recording and discard the file */
321 AST_CONTROL_RECORD_STOP = 1101, /*!< Indicated to a channel in record to stop recording */
322 AST_CONTROL_RECORD_SUSPEND = 1102, /*!< Indicated to a channel in record to suspend/unsuspend recording */
323 AST_CONTROL_RECORD_MUTE = 1103, /*!< Indicated to a channel in record to mute/unmute (i.e. write silence) recording */
326 enum ast_frame_read_action {
327 AST_FRAME_READ_ACTION_CONNECTED_LINE_MACRO,
330 struct ast_control_read_action_payload {
331 /* An indicator to ast_read of what action to
332 * take with the frame;
334 enum ast_frame_read_action action;
335 /* The size of the frame's payload
338 /* A payload for the frame.
340 unsigned char payload[0];
343 enum ast_control_t38 {
344 AST_T38_REQUEST_NEGOTIATE = 1, /*!< Request T38 on a channel (voice to fax) */
345 AST_T38_REQUEST_TERMINATE, /*!< Terminate T38 on a channel (fax to voice) */
346 AST_T38_NEGOTIATED, /*!< T38 negotiated (fax mode) */
347 AST_T38_TERMINATED, /*!< T38 terminated (back to voice) */
348 AST_T38_REFUSED, /*!< T38 refused for some reason (usually rejected by remote end) */
349 AST_T38_REQUEST_PARMS, /*!< request far end T.38 parameters for a channel in 'negotiating' state */
352 enum ast_control_t38_rate {
353 AST_T38_RATE_2400 = 1,
358 /* Set to 0 so it's taken as default when unspecified.
359 * See ITU-T T.38 Implementors' Guide (11 May 2012),
360 * Table H.2: if the T38MaxBitRate attribute is omitted
361 * it should use a default of 14400. */
362 AST_T38_RATE_14400 = 0,
365 enum ast_control_t38_rate_management {
366 AST_T38_RATE_MANAGEMENT_TRANSFERRED_TCF = 0,
367 AST_T38_RATE_MANAGEMENT_LOCAL_TCF,
370 struct ast_control_t38_parameters {
371 enum ast_control_t38 request_response; /*!< Request or response of the T38 control frame */
372 unsigned int version; /*!< Supported T.38 version */
373 unsigned int max_ifp; /*!< Maximum IFP size supported */
374 enum ast_control_t38_rate rate; /*!< Maximum fax rate supported */
375 enum ast_control_t38_rate_management rate_management; /*!< Rate management setting */
376 unsigned int fill_bit_removal:1; /*!< Set if fill bit removal can be used */
377 unsigned int transcoding_mmr:1; /*!< Set if MMR transcoding can be used */
378 unsigned int transcoding_jbig:1; /*!< Set if JBIG transcoding can be used */
381 enum ast_control_transfer {
382 AST_TRANSFER_SUCCESS = 0, /*!< Transfer request on the channel worked */
383 AST_TRANSFER_FAILED, /*!< Transfer request on the channel failed */
386 struct ast_control_pvt_cause_code {
387 char chan_name[AST_CHANNEL_NAME]; /*!< Name of the channel that originated the cause information */
388 unsigned int emulate_sip_cause:1; /*!< Indicates whether this should be used to emulate SIP_CAUSE support */
389 int ast_cause; /*!< Asterisk cause code associated with this message */
390 char code[1]; /*!< Tech-specific cause code information, beginning with the name of the tech */
393 /* Option identifiers and flags */
394 #define AST_OPTION_FLAG_REQUEST 0
395 #define AST_OPTION_FLAG_ACCEPT 1
396 #define AST_OPTION_FLAG_REJECT 2
397 #define AST_OPTION_FLAG_QUERY 4
398 #define AST_OPTION_FLAG_ANSWER 5
399 #define AST_OPTION_FLAG_WTF 6
401 /*! Verify touchtones by muting audio transmission
402 * (and reception) and verify the tone is still present
403 * Option data is a single signed char value 0 or 1 */
404 #define AST_OPTION_TONE_VERIFY 1
406 /*! Put a compatible channel into TDD (TTY for the hearing-impared) mode
407 * Option data is a single signed char value 0 or 1 */
408 #define AST_OPTION_TDD 2
410 /*! Relax the parameters for DTMF reception (mainly for radio use)
411 * Option data is a single signed char value 0 or 1 */
412 #define AST_OPTION_RELAXDTMF 3
414 /*! Set (or clear) Audio (Not-Clear) Mode
415 * Option data is a single signed char value 0 or 1 */
416 #define AST_OPTION_AUDIO_MODE 4
418 /*! Set channel transmit gain
419 * Option data is a single signed char representing number of decibels (dB)
420 * to set gain to (on top of any gain specified in channel driver) */
421 #define AST_OPTION_TXGAIN 5
423 /*! Set channel receive gain
424 * Option data is a single signed char representing number of decibels (dB)
425 * to set gain to (on top of any gain specified in channel driver) */
426 #define AST_OPTION_RXGAIN 6
428 /* set channel into "Operator Services" mode
429 * Option data is a struct oprmode
431 * \note This option should never be sent over the network */
432 #define AST_OPTION_OPRMODE 7
434 /*! Explicitly enable or disable echo cancelation for the given channel
435 * Option data is a single signed char value 0 or 1
437 * \note This option appears to be unused in the code. It is handled, but never
439 #define AST_OPTION_ECHOCAN 8
441 /*! \brief Handle channel write data
442 * If a channel needs to process the data from a func_channel write operation
443 * after func_channel_write executes, it can define the setoption callback
444 * and process this option. A pointer to an ast_chan_write_info_t will be passed.
446 * \note This option should never be passed over the network. */
447 #define AST_OPTION_CHANNEL_WRITE 9
450 * Read-only. Allows query current status of T38 on the channel.
453 #define AST_OPTION_T38_STATE 10
455 /*! Request that the channel driver deliver frames in a specific format
456 * Option data is a format_t */
457 #define AST_OPTION_FORMAT_READ 11
459 /*! Request that the channel driver be prepared to accept frames in a specific format
460 * Option data is a format_t */
461 #define AST_OPTION_FORMAT_WRITE 12
463 /*! Request that the channel driver make two channels of the same tech type compatible if possible
464 * Option data is an ast_channel
466 * \note This option should never be passed over the network */
467 #define AST_OPTION_MAKE_COMPATIBLE 13
469 /*! Get or set the digit detection state of the channel
470 * Option data is a single signed char value 0 or 1 */
471 #define AST_OPTION_DIGIT_DETECT 14
473 /*! Get or set the fax tone detection state of the channel
474 * Option data is a single signed char value 0 or 1 */
475 #define AST_OPTION_FAX_DETECT 15
477 /*! Get the device name from the channel (Read only)
478 * Option data is a character buffer of suitable length */
479 #define AST_OPTION_DEVICE_NAME 16
481 /*! Get the CC agent type from the channel (Read only)
482 * Option data is a character buffer of suitable length */
483 #define AST_OPTION_CC_AGENT_TYPE 17
485 /*! Get or set the security options on a channel
486 * Option data is an integer value of 0 or 1 */
487 #define AST_OPTION_SECURE_SIGNALING 18
488 #define AST_OPTION_SECURE_MEDIA 19
491 struct ast_channel *peer;
495 struct ast_option_header {
496 /* Always keep in network byte order */
497 #if __BYTE_ORDER == __BIG_ENDIAN
501 #if __BYTE_ORDER == __LITTLE_ENDIAN
505 #error Byte order not defined
511 /*! \brief Requests a frame to be allocated
514 * Request a frame be allocated. source is an optional source of the frame,
515 * len is the requested length, or "0" if the caller will supply the buffer
517 #if 0 /* Unimplemented */
518 struct ast_frame *ast_fralloc(char *source, int len);
522 * \brief Frees a frame or list of frames
524 * \param fr Frame to free, or head of list to free
525 * \param cache Whether to consider this frame for frame caching
527 void ast_frame_free(struct ast_frame *fr, int cache);
529 #define ast_frfree(fr) ast_frame_free(fr, 1)
532 * \brief NULL-safe wrapper for \ref ast_frfree, good for \ref RAII_VAR.
533 * \param frame Frame to free, or head of list to free.
535 void ast_frame_dtor(struct ast_frame *frame);
537 /*! \brief Makes a frame independent of any static storage
538 * \param fr frame to act upon
539 * Take a frame, and if it's not been malloc'd, make a malloc'd copy
540 * and if the data hasn't been malloced then make the
541 * data malloc'd. If you need to store frames, say for queueing, then
542 * you should call this function.
543 * \return Returns a frame on success, NULL on error
544 * \note This function may modify the frame passed to it, so you must
545 * not assume the frame will be intact after the isolated frame has
546 * been produced. In other words, calling this function on a frame
547 * should be the last operation you do with that frame before freeing
548 * it (or exiting the block, if the frame is on the stack.)
550 struct ast_frame *ast_frisolate(struct ast_frame *fr);
552 /*! \brief Copies a frame
553 * \param fr frame to copy
554 * Duplicates a frame -- should only rarely be used, typically frisolate is good enough
555 * \return Returns a frame on success, NULL on error
557 struct ast_frame *ast_frdup(const struct ast_frame *fr);
559 void ast_swapcopy_samples(void *dst, const void *src, int samples);
561 /* Helpers for byteswapping native samples to/from
562 little-endian and big-endian. */
563 #if __BYTE_ORDER == __LITTLE_ENDIAN
564 #define ast_frame_byteswap_le(fr) do { ; } while(0)
565 #define ast_frame_byteswap_be(fr) do { struct ast_frame *__f = (fr); ast_swapcopy_samples(__f->data.ptr, __f->data.ptr, __f->samples); } while(0)
567 #define ast_frame_byteswap_le(fr) do { struct ast_frame *__f = (fr); ast_swapcopy_samples(__f->data.ptr, __f->data.ptr, __f->samples); } while(0)
568 #define ast_frame_byteswap_be(fr) do { ; } while(0)
571 void ast_frame_dump(const char *name, struct ast_frame *f, char *prefix);
573 /*! \brief Appends a frame to the end of a list of frames, truncating the maximum length of the list */
574 struct ast_frame *ast_frame_enqueue(struct ast_frame *head, struct ast_frame *f, int maxlen, int dupe);
577 \brief Adjusts the volume of the audio samples contained in a frame.
578 \param f The frame containing the samples (must be AST_FRAME_VOICE and AST_FORMAT_SLINEAR)
579 \param adjustment The number of dB to adjust up or down.
580 \return 0 for success, non-zero for an error
582 int ast_frame_adjust_volume(struct ast_frame *f, int adjustment);
585 \brief Sums two frames of audio samples.
586 \param f1 The first frame (which will contain the result)
587 \param f2 The second frame
588 \return 0 for success, non-zero for an error
590 The frames must be AST_FRAME_VOICE and must contain AST_FORMAT_SLINEAR samples,
591 and must contain the same number of samples.
593 int ast_frame_slinear_sum(struct ast_frame *f1, struct ast_frame *f2);
596 * \brief Clear all audio samples from an ast_frame. The frame must be AST_FRAME_VOICE and AST_FORMAT_SLINEAR
598 int ast_frame_clear(struct ast_frame *frame);
601 * \brief Copy the discription of a frame's subclass into the provided string
603 * \param f The frame to get the information from
604 * \param subclass Buffer to fill with subclass information
605 * \param slen Length of subclass buffer
606 * \param moreinfo Buffer to fill with additional information
607 * \param mlen Length of moreinfo buffer
610 void ast_frame_subclass2str(struct ast_frame *f, char *subclass, size_t slen, char *moreinfo, size_t mlen);
613 * \brief Copy the discription of a frame type into the provided string
615 * \param frame_type The frame type to be described
616 * \param ftype Buffer to fill with frame type description
617 * \param len Length of subclass buffer
620 void ast_frame_type2str(enum ast_frame_type frame_type, char *ftype, size_t len);
622 #if defined(__cplusplus) || defined(c_plusplus)
626 #endif /* _ASTERISK_FRAME_H */