Wed Oct 28 15:47:54 2009

Asterisk developer's documentation


frame.h

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 1999 - 2005, Digium, Inc.
00005  *
00006  * Mark Spencer <markster@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  */
00018 
00019 /*! \file
00020  * \brief Asterisk internal frame definitions.
00021  * \arg For an explanation of frames, see \ref Def_Frame
00022  * \arg Frames are send of Asterisk channels, see \ref Def_Channel
00023  */
00024 
00025 #ifndef _ASTERISK_FRAME_H
00026 #define _ASTERISK_FRAME_H
00027 
00028 #if defined(__cplusplus) || defined(c_plusplus)
00029 extern "C" {
00030 #endif
00031 
00032 #include <sys/types.h>
00033 #include <sys/time.h>
00034 #include "asterisk/endian.h"
00035 
00036 struct ast_codec_pref {
00037    char order[32];
00038 };
00039 
00040 /*! \page Def_Frame AST Multimedia and signalling frames
00041    \section Def_AstFrame What is an ast_frame ?
00042    A frame of data read used to communicate between 
00043    between channels and applications.
00044    Frames are divided into frame types and subclasses.
00045 
00046    \par Frame types 
00047    \arg \b VOICE: Voice data, subclass is codec (AST_FORMAT_*)
00048    \arg \b VIDEO: Video data, subclass is codec (AST_FORMAT_*)
00049    \arg \b DTMF:  A DTMF digit, subclass is the digit
00050    \arg \b IMAGE: Image transport, mostly used in IAX
00051    \arg \b TEXT:  Text messages
00052    \arg \b HTML:  URL's and web pages
00053    \arg \b T38:   T38 Fax transport frames
00054    \arg \b IAX:   Private frame type for the IAX protocol
00055    \arg \b CNG:   Comfort noice frames
00056    \arg \b CONTROL:  A control frame, subclass defined as AST_CONTROL_
00057    \arg \b NULL:  Empty, useless frame
00058 
00059    \par Files
00060    \arg frame.h   Definitions
00061    \arg frame.c   Function library
00062    \arg \ref Def_Channel Asterisk channels
00063    \section Def_ControlFrame Control Frames
00064    Control frames send signalling information between channels
00065    and devices. They are prefixed with AST_CONTROL_, like AST_CONTROL_FRAME_HANGUP
00066    \arg \b HANGUP The other end has hungup
00067    \arg \b RING   Local ring
00068    \arg \b RINGING   The other end is ringing
00069    \arg \b ANSWER The other end has answered
00070    \arg \b BUSY   Remote end is busy
00071    \arg \b TAKEOFFHOOK  Make it go off hook (what's "it" ? )
00072    \arg \b OFFHOOK   Line is off hook
00073    \arg \b CONGESTION   Congestion (circuit is busy, not available)
00074    \arg \b FLASH  Other end sends flash hook
00075    \arg \b WINK   Other end sends wink
00076    \arg \b OPTION Send low-level option
00077    \arg \b RADIO_KEY Key radio (see app_rpt.c)
00078    \arg \b RADIO_UNKEY  Un-key radio (see app_rpt.c)
00079    \arg \b PROGRESS  Other end indicates call progress
00080    \arg \b PROCEEDING   Indicates proceeding
00081    \arg \b HOLD   Call is placed on hold
00082    \arg \b UNHOLD Call is back from hold
00083    \arg \b VIDUPDATE Video update requested
00084 
00085 */
00086 
00087 /*! \brief Data structure associated with a single frame of data
00088  */
00089 struct ast_frame {
00090    /*! Kind of frame */
00091    int frametype;          
00092    /*! Subclass, frame dependent */
00093    int subclass;           
00094    /*! Length of data */
00095    int datalen;            
00096    /*! Number of 8khz samples in this frame */
00097    int samples;            
00098    /*! Was the data malloc'd?  i.e. should we free it when we discard the frame? */
00099    int mallocd;            
00100    /*! How many bytes exist _before_ "data" that can be used if needed */
00101    int offset;          
00102    /*! Optional source of frame for debugging */
00103    const char *src;           
00104    /*! Pointer to actual data */
00105    void *data;    
00106    /*! Global delivery time */      
00107    struct timeval delivery;
00108    /*! Next/Prev for linking stand alone frames */
00109    struct ast_frame *prev;       
00110    /*! Next/Prev for linking stand alone frames */
00111    struct ast_frame *next;       
00112 };
00113 
00114 #define AST_FRIENDLY_OFFSET   64 /*! It's polite for a a new frame to
00115                  have this number of bytes for additional
00116                  headers.  */
00117 #define AST_MIN_OFFSET     32 /*! Make sure we keep at least this much handy */
00118 
00119 /*! Need the header be free'd? */
00120 #define AST_MALLOCD_HDR    (1 << 0)
00121 /*! Need the data be free'd? */
00122 #define AST_MALLOCD_DATA   (1 << 1)
00123 /*! Need the source be free'd? (haha!) */
00124 #define AST_MALLOCD_SRC    (1 << 2)
00125 
00126 /* Frame types */
00127 /*! A DTMF digit, subclass is the digit */
00128 #define AST_FRAME_DTMF     1
00129 /*! Voice data, subclass is AST_FORMAT_* */
00130 #define AST_FRAME_VOICE    2
00131 /*! Video frame, maybe?? :) */
00132 #define AST_FRAME_VIDEO    3
00133 /*! A control frame, subclass is AST_CONTROL_* */
00134 #define AST_FRAME_CONTROL  4
00135 /*! An empty, useless frame */
00136 #define AST_FRAME_NULL     5
00137 /*! Inter Asterisk Exchange private frame type */
00138 #define AST_FRAME_IAX      6
00139 /*! Text messages */
00140 #define AST_FRAME_TEXT     7
00141 /*! Image Frames */
00142 #define AST_FRAME_IMAGE    8
00143 /*! HTML Frame */
00144 #define AST_FRAME_HTML     9
00145 /*! Comfort Noise frame (subclass is level of CNG in -dBov), 
00146     body may include zero or more 8-bit quantization coefficients */
00147 #define AST_FRAME_CNG      10
00148 /*! T.38 Fax-over-IP data stream */
00149 #define AST_FRAME_T38      11
00150 
00151 /* HTML subclasses */
00152 /*! Sending a URL */
00153 #define AST_HTML_URL    1
00154 /*! Data frame */
00155 #define AST_HTML_DATA      2
00156 /*! Beginning frame */
00157 #define AST_HTML_BEGIN     4
00158 /*! End frame */
00159 #define AST_HTML_END    8
00160 /*! Load is complete */
00161 #define AST_HTML_LDCOMPLETE   16
00162 /*! Peer is unable to support HTML */
00163 #define AST_HTML_NOSUPPORT 17
00164 /*! Send URL, and track */
00165 #define AST_HTML_LINKURL   18
00166 /*! No more HTML linkage */
00167 #define AST_HTML_UNLINK    19
00168 /*! Reject link request */
00169 #define AST_HTML_LINKREJECT   20
00170 
00171 /* Data formats for capabilities and frames alike */
00172 /*! G.723.1 compression */
00173 #define AST_FORMAT_G723_1  (1 << 0)
00174 /*! GSM compression */
00175 #define AST_FORMAT_GSM     (1 << 1)
00176 /*! Raw mu-law data (G.711) */
00177 #define AST_FORMAT_ULAW    (1 << 2)
00178 /*! Raw A-law data (G.711) */
00179 #define AST_FORMAT_ALAW    (1 << 3)
00180 /*! ADPCM (G.726, 32kbps) */
00181 #define AST_FORMAT_G726    (1 << 4)
00182 /*! ADPCM (IMA) */
00183 #define AST_FORMAT_ADPCM   (1 << 5)
00184 /*! Raw 16-bit Signed Linear (8000 Hz) PCM */
00185 #define AST_FORMAT_SLINEAR (1 << 6)
00186 /*! LPC10, 180 samples/frame */
00187 #define AST_FORMAT_LPC10   (1 << 7)
00188 /*! G.729A audio */
00189 #define AST_FORMAT_G729A   (1 << 8)
00190 /*! SpeeX Free Compression */
00191 #define AST_FORMAT_SPEEX   (1 << 9)
00192 /*! iLBC Free Compression */
00193 #define AST_FORMAT_ILBC    (1 << 10)
00194 /*! Maximum audio format */
00195 #define AST_FORMAT_MAX_AUDIO  (1 << 15)
00196 /*! JPEG Images */
00197 #define AST_FORMAT_JPEG    (1 << 16)
00198 /*! PNG Images */
00199 #define AST_FORMAT_PNG     (1 << 17)
00200 /*! H.261 Video */
00201 #define AST_FORMAT_H261    (1 << 18)
00202 /*! H.263 Video */
00203 #define AST_FORMAT_H263    (1 << 19)
00204 /*! H.263+ Video */
00205 #define AST_FORMAT_H263_PLUS  (1 << 20)
00206 /*! Maximum video format */
00207 #define AST_FORMAT_MAX_VIDEO  (1 << 24)
00208 
00209 /* Control frame types */
00210 /*! Other end has hungup */
00211 #define AST_CONTROL_HANGUP    1
00212 /*! Local ring */
00213 #define AST_CONTROL_RING      2
00214 /*! Remote end is ringing */
00215 #define AST_CONTROL_RINGING      3
00216 /*! Remote end has answered */
00217 #define AST_CONTROL_ANSWER    4
00218 /*! Remote end is busy */
00219 #define AST_CONTROL_BUSY      5
00220 /*! Make it go off hook */
00221 #define AST_CONTROL_TAKEOFFHOOK     6
00222 /*! Line is off hook */
00223 #define AST_CONTROL_OFFHOOK      7
00224 /*! Congestion (circuits busy) */
00225 #define AST_CONTROL_CONGESTION      8
00226 /*! Flash hook */
00227 #define AST_CONTROL_FLASH     9
00228 /*! Wink */
00229 #define AST_CONTROL_WINK      10
00230 /*! Set a low-level option */
00231 #define AST_CONTROL_OPTION    11
00232 /*! Key Radio */
00233 #define  AST_CONTROL_RADIO_KEY      12
00234 /*! Un-Key Radio */
00235 #define  AST_CONTROL_RADIO_UNKEY    13
00236 /*! Indicate PROGRESS */
00237 #define AST_CONTROL_PROGRESS            14
00238 /*! Indicate CALL PROCEEDING */
00239 #define AST_CONTROL_PROCEEDING      15
00240 /*! Indicate call is placed on hold */
00241 #define AST_CONTROL_HOLD         16
00242 /*! Indicate call is left from hold */
00243 #define AST_CONTROL_UNHOLD       17
00244 /*! Indicate video frame update */
00245 #define AST_CONTROL_VIDUPDATE    18
00246 
00247 #define AST_SMOOTHER_FLAG_G729      (1 << 0)
00248 
00249 /* Option identifiers and flags */
00250 #define AST_OPTION_FLAG_REQUEST     0
00251 #define AST_OPTION_FLAG_ACCEPT      1
00252 #define AST_OPTION_FLAG_REJECT      2
00253 #define AST_OPTION_FLAG_QUERY    4
00254 #define AST_OPTION_FLAG_ANSWER      5
00255 #define AST_OPTION_FLAG_WTF      6
00256 
00257 /*! Verify touchtones by muting audio transmission 
00258    (and reception) and verify the tone is still present */
00259 #define AST_OPTION_TONE_VERIFY      1     
00260 
00261 /*! Put a compatible channel into TDD (TTY for the hearing-impared) mode */
00262 #define  AST_OPTION_TDD       2
00263 
00264 /*! Relax the parameters for DTMF reception (mainly for radio use) */
00265 #define  AST_OPTION_RELAXDTMF    3
00266 
00267 /*! Set (or clear) Audio (Not-Clear) Mode */
00268 #define  AST_OPTION_AUDIO_MODE      4
00269 
00270 /*! Set channel transmit gain 
00271  * Option data is a single signed char
00272    representing number of decibels (dB)
00273    to set gain to (on top of any gain
00274    specified in channel driver)
00275 */
00276 #define AST_OPTION_TXGAIN     5
00277 
00278 /*! Set channel receive gain
00279  * Option data is a single signed char
00280    representing number of decibels (dB)
00281    to set gain to (on top of any gain
00282    specified in channel driver)
00283 */
00284 #define AST_OPTION_RXGAIN     6
00285 
00286 struct ast_option_header {
00287    /* Always keep in network byte order */
00288 #if __BYTE_ORDER == __BIG_ENDIAN
00289         u_int16_t flag:3;
00290         u_int16_t option:13;
00291 #else
00292 #if __BYTE_ORDER == __LITTLE_ENDIAN
00293         u_int16_t option:13;
00294         u_int16_t flag:3;
00295 #else
00296 #error Byte order not defined
00297 #endif
00298 #endif
00299       u_int8_t data[0];
00300 };
00301 
00302 /*! \brief  Requests a frame to be allocated 
00303  * 
00304  * \param source 
00305  * Request a frame be allocated.  source is an optional source of the frame, 
00306  * len is the requested length, or "0" if the caller will supply the buffer 
00307  */
00308 #if 0 /* Unimplemented */
00309 struct ast_frame *ast_fralloc(char *source, int len);
00310 #endif
00311 
00312 /*!  \brief Frees a frame 
00313  * \param fr Frame to free
00314  * Free a frame, and the memory it used if applicable
00315  * \return no return.
00316  */
00317 void ast_frfree(struct ast_frame *fr);
00318 
00319 /*! \brief Copies a frame 
00320  * \param fr frame to act upon
00321  * Take a frame, and if it's not been malloc'd, make a malloc'd copy
00322  * and if the data hasn't been malloced then make the
00323  * data malloc'd.  If you need to store frames, say for queueing, then
00324  * you should call this function.
00325  * \return Returns a frame on success, NULL on error
00326  */
00327 struct ast_frame *ast_frisolate(struct ast_frame *fr);
00328 
00329 /*! \brief Copies a frame 
00330  * \param fr frame to copy
00331  * Dupliates a frame -- should only rarely be used, typically frisolate is good enough
00332  * \return Returns a frame on success, NULL on error
00333  */
00334 struct ast_frame *ast_frdup(struct ast_frame *fr);
00335 
00336 /*! \brief Reads a frame from an fd
00337  * Read a frame from a stream or packet fd, as written by fd_write
00338  * \param fd an opened fd to read from
00339  * \return returns a frame on success, NULL on error
00340  */
00341 struct ast_frame *ast_fr_fdread(int fd);
00342 
00343 /*! Writes a frame to an fd
00344  * Write a frame to an fd
00345  * \param fd Which fd to write to
00346  * \param frame frame to write to the fd
00347  * \return Returns 0 on success, -1 on failure
00348  */
00349 int ast_fr_fdwrite(int fd, struct ast_frame *frame);
00350 
00351 /*! \brief Sends a hangup to an fd 
00352  * Send a hangup (NULL equivalent) on an fd
00353  * \param fd fd to write to
00354  * \return Returns 0 on success, -1 on failure
00355  */
00356 int ast_fr_fdhangup(int fd);
00357 
00358 void ast_swapcopy_samples(void *dst, const void *src, int samples);
00359 
00360 /* Helpers for byteswapping native samples to/from 
00361    little-endian and big-endian. */
00362 #if __BYTE_ORDER == __LITTLE_ENDIAN
00363 #define ast_frame_byteswap_le(fr) do { ; } while(0)
00364 #define ast_frame_byteswap_be(fr) do { struct ast_frame *__f = (fr); ast_swapcopy_samples(__f->data, __f->data, __f->samples); } while(0)
00365 #else
00366 #define ast_frame_byteswap_le(fr) do { struct ast_frame *__f = (fr); ast_swapcopy_samples(__f->data, __f->data, __f->samples); } while(0)
00367 #define ast_frame_byteswap_be(fr) do { ; } while(0)
00368 #endif
00369 
00370 
00371 /*! \brief Get the name of a format
00372  * \param format id of format
00373  * \return A static string containing the name of the format or "UNKN" if unknown.
00374  */
00375 extern char* ast_getformatname(int format);
00376 
00377 /*! \brief Get the names of a set of formats
00378  * \param buf a buffer for the output string
00379  * \param size size of buf (bytes)
00380  * \param format the format (combined IDs of codecs)
00381  * Prints a list of readable codec names corresponding to "format".
00382  * ex: for format=AST_FORMAT_GSM|AST_FORMAT_SPEEX|AST_FORMAT_ILBC it will return "0x602 (GSM|SPEEX|ILBC)"
00383  * \return The return value is buf.
00384  */
00385 extern char* ast_getformatname_multiple(char *buf, size_t size, int format);
00386 
00387 /*!
00388  * \brief Gets a format from a name.
00389  * \param name string of format
00390  * \return This returns the form of the format in binary on success, 0 on error.
00391  */
00392 extern int ast_getformatbyname(char *name);
00393 
00394 /*! \brief Get a name from a format 
00395  * Gets a name from a format
00396  * \param codec codec number (1,2,4,8,16,etc.)
00397  * \return This returns a static string identifying the format on success, 0 on error.
00398  */
00399 extern char *ast_codec2str(int codec);
00400 
00401 struct ast_smoother;
00402 
00403 extern struct ast_format_list *ast_get_format_list_index(int index);
00404 extern struct ast_format_list *ast_get_format_list(size_t *size);
00405 extern struct ast_smoother *ast_smoother_new(int bytes);
00406 extern void ast_smoother_set_flags(struct ast_smoother *smoother, int flags);
00407 extern int ast_smoother_get_flags(struct ast_smoother *smoother);
00408 extern void ast_smoother_free(struct ast_smoother *s);
00409 extern void ast_smoother_reset(struct ast_smoother *s, int bytes);
00410 extern int __ast_smoother_feed(struct ast_smoother *s, struct ast_frame *f, int swap);
00411 extern struct ast_frame *ast_smoother_read(struct ast_smoother *s);
00412 #define ast_smoother_feed(s,f) __ast_smoother_feed(s, f, 0)
00413 #if __BYTE_ORDER == __LITTLE_ENDIAN
00414 #define ast_smoother_feed_be(s,f) __ast_smoother_feed(s, f, 1)
00415 #define ast_smoother_feed_le(s,f) __ast_smoother_feed(s, f, 0)
00416 #else
00417 #define ast_smoother_feed_be(s,f) __ast_smoother_feed(s, f, 0)
00418 #define ast_smoother_feed_le(s,f) __ast_smoother_feed(s, f, 1)
00419 #endif
00420 
00421 extern void ast_frame_dump(char *name, struct ast_frame *f, char *prefix);
00422 
00423 /*! \brief Initialize a codec preference to "no preference" */
00424 extern void ast_codec_pref_init(struct ast_codec_pref *pref);
00425 
00426 /*! \brief Codec located at  a particular place in the preference index */
00427 extern int ast_codec_pref_index(struct ast_codec_pref *pref, int index);
00428 
00429 /*! \brief Remove a codec from a preference list */
00430 extern void ast_codec_pref_remove(struct ast_codec_pref *pref, int format);
00431 
00432 /*! \brief Append a codec to a preference list, removing it first if it was already there */
00433 extern int ast_codec_pref_append(struct ast_codec_pref *pref, int format);
00434 
00435 /*! \brief Select the best format according to preference list from supplied options. 
00436    If "find_best" is non-zero then if nothing is found, the "Best" format of 
00437    the format list is selected, otherwise 0 is returned. */
00438 extern int ast_codec_choose(struct ast_codec_pref *pref, int formats, int find_best);
00439 
00440 /*! \brief Parse an "allow" or "deny" line and update the mask and pref if provided */
00441 extern void ast_parse_allow_disallow(struct ast_codec_pref *pref, int *mask, const char *list, int allowing);
00442 
00443 /*! \brief Dump codec preference list into a string */
00444 extern int ast_codec_pref_string(struct ast_codec_pref *pref, char *buf, size_t size);
00445 
00446 /*! \brief Shift a codec preference list up or down 65 bytes so that it becomes an ASCII string */
00447 extern void ast_codec_pref_convert(struct ast_codec_pref *pref, char *buf, size_t size, int right);
00448 
00449 /*! \brief Returns the number of samples contained in the frame */
00450 extern int ast_codec_get_samples(struct ast_frame *f);
00451 
00452 /*! \brief Returns the number of bytes for the number of samples of the given format */
00453 extern int ast_codec_get_len(int format, int samples);
00454 
00455 /*! \brief Gets duration in ms of interpolation frame for a format */
00456 static inline int ast_codec_interp_len(int format) 
00457 { 
00458    return (format == AST_FORMAT_ILBC) ? 30 : 20;
00459 }
00460 
00461 /*!
00462   \brief Adjusts the volume of the audio samples contained in a frame.
00463   \param f The frame containing the samples (must be AST_FRAME_VOICE and AST_FORMAT_SLINEAR)
00464   \param adjustment The number of dB to adjust up or down.
00465   \return 0 for success, non-zero for an error
00466  */
00467 int ast_frame_adjust_volume(struct ast_frame *f, int adjustment);
00468 
00469 /*!
00470   \brief Sums two frames of audio samples.
00471   \param f1 The first frame (which will contain the result)
00472   \param f2 The second frame
00473   \return 0 for success, non-zero for an error
00474 
00475   The frames must be AST_FRAME_VOICE and must contain AST_FORMAT_SLINEAR samples,
00476   and must contain the same number of samples.
00477  */
00478 int ast_frame_slinear_sum(struct ast_frame *f1, struct ast_frame *f2);
00479 
00480 #if defined(__cplusplus) || defined(c_plusplus)
00481 }
00482 #endif
00483 
00484 #endif /* _ASTERISK_FRAME_H */

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