00001 /* 00002 * Asterisk -- An open source telephony toolkit. 00003 * 00004 * Copyright (C) 1999 - 2006, 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 Support for translation of data formats. 00021 */ 00022 00023 #ifndef _ASTERISK_TRANSLATE_H 00024 #define _ASTERISK_TRANSLATE_H 00025 00026 #define MAX_AUDIO_FORMAT 15 /* Do not include video here */ 00027 #define MAX_FORMAT 32 /* Do include video here */ 00028 00029 #if defined(__cplusplus) || defined(c_plusplus) 00030 extern "C" { 00031 #endif 00032 00033 #if 1 /* need lots of stuff... */ 00034 #include "asterisk/frame.h" 00035 #include "asterisk/plc.h" 00036 #include "asterisk/linkedlists.h" 00037 // XXX #include "asterisk/module.h" 00038 #endif 00039 00040 struct ast_trans_pvt; /* declared below */ 00041 00042 /*! \brief 00043 * Descriptor of a translator. Name, callbacks, and various options 00044 * related to run-time operation (size of buffers, auxiliary 00045 * descriptors, etc). 00046 * 00047 * A coded registers itself by filling the relevant fields 00048 * of a structure and passing it as an argument to 00049 * ast_register_translator(). The structure should not be 00050 * modified after a successful registration, and its address 00051 * must be used as an argument to ast_unregister_translator(). 00052 * 00053 * As a minimum, a translator should supply name, srcfmt and dstfmt, 00054 * the required buf_size (in bytes) and buffer_samples (in samples), 00055 * and a few callbacks (framein, frameout, sample). 00056 * The outbuf is automatically prepended by AST_FRIENDLY_OFFSET 00057 * spare bytes so generic routines can place data in there. 00058 * 00059 * Note, the translator is not supposed to do any memory allocation 00060 * or deallocation, nor any locking, because all of this is done in 00061 * the generic code. 00062 * 00063 * Translators using generic plc (packet loss concealment) should 00064 * supply a non-zero plc_samples indicating the size (in samples) 00065 * of artificially generated frames and incoming data. 00066 * Generic plc is only available for dstfmt = SLINEAR 00067 */ 00068 struct ast_translator { 00069 const char name[80]; /*!< Name of translator */ 00070 int srcfmt; /*!< Source format (note: bit position, 00071 converted to index during registration) */ 00072 int dstfmt; /*!< Destination format (note: bit position, 00073 converted to index during registration) */ 00074 00075 int (*newpvt)(struct ast_trans_pvt *); /*!< initialize private data 00076 associated with the translator */ 00077 00078 int (*framein)(struct ast_trans_pvt *pvt, struct ast_frame *in); 00079 /*!< Input frame callback. Store 00080 (and possibly convert) input frame. */ 00081 00082 struct ast_frame * (*frameout)(struct ast_trans_pvt *pvt); 00083 /*!< Output frame callback. Generate a frame 00084 with outbuf content. */ 00085 00086 void (*destroy)(struct ast_trans_pvt *pvt); 00087 /*!< cleanup private data, if needed 00088 (often unnecessary). */ 00089 00090 struct ast_frame * (*sample)(void); /*!< Generate an example frame */ 00091 00092 /*! \brief size of outbuf, in samples. Leave it 0 if you want the framein 00093 * callback deal with the frame. Set it appropriately if you 00094 * want the code to checks if the incoming frame fits the 00095 * outbuf (this is e.g. required for plc). 00096 */ 00097 int buffer_samples; /*< size of outbuf, in samples */ 00098 00099 /*! \brief size of outbuf, in bytes. Mandatory. The wrapper code will also 00100 * allocate an AST_FRIENDLY_OFFSET space before. 00101 */ 00102 int buf_size; 00103 00104 int desc_size; /*!< size of private descriptor in pvt->pvt, if any */ 00105 int plc_samples; /*!< set to the plc block size if used, 0 otherwise */ 00106 int useplc; /*!< current status of plc, changed at runtime */ 00107 int native_plc; /*!< true if the translator can do native plc */ 00108 00109 struct ast_module *module; /* opaque reference to the parent module */ 00110 00111 int cost; /*!< Cost in milliseconds for encoding/decoding 1 second of sound */ 00112 int active; /*!< Whether this translator should be used or not */ 00113 AST_LIST_ENTRY(ast_translator) list; /*!< link field */ 00114 }; 00115 00116 /*! \brief 00117 * Default structure for translators, with the basic fields and buffers, 00118 * all allocated as part of the same chunk of memory. The buffer is 00119 * preceded by AST_FRIENDLY_OFFSET bytes in front of the user portion. 00120 * 'buf' points right after this space. 00121 * 00122 * *_framein() routines operate in two ways: 00123 * 1. some convert on the fly and place the data directly in outbuf; 00124 * in this case 'samples' and 'datalen' contain the number of samples 00125 * and number of bytes available in the buffer. 00126 * In this case we can use a generic *_frameout() routine that simply 00127 * takes whatever is there and places it into the output frame. 00128 * 2. others simply store the (unconverted) samples into a working 00129 * buffer, and leave the conversion task to *_frameout(). 00130 * In this case, the intermediate buffer must be in the private 00131 * descriptor, 'datalen' is left to 0, while 'samples' is still 00132 * updated with the number of samples received. 00133 */ 00134 struct ast_trans_pvt { 00135 struct ast_translator *t; 00136 struct ast_frame f; /*!< used in frameout */ 00137 int samples; /*!< samples available in outbuf */ 00138 /*! 00139 * \brief actual space used in outbuf 00140 * 00141 * Also, for the sake of ABI compatability, a magic value of -1 in this 00142 * field means that the pvt has been requested to be destroyed, but is 00143 * pending destruction until ast_translate_frame_freed() gets called. 00144 */ 00145 int datalen; 00146 void *pvt; /*!< more private data, if any */ 00147 char *outbuf; /*!< the useful portion of the buffer */ 00148 plc_state_t *plc; /*!< optional plc pointer */ 00149 struct ast_trans_pvt *next; /*!< next in translator chain */ 00150 struct timeval nextin; 00151 struct timeval nextout; 00152 }; 00153 00154 /*! \brief generic frameout function */ 00155 struct ast_frame *ast_trans_frameout(struct ast_trans_pvt *pvt, 00156 int datalen, int samples); 00157 00158 struct ast_trans_pvt; 00159 00160 /*! 00161 * \brief Register a translator 00162 * This registers a codec translator with asterisk 00163 * \param t populated ast_translator structure 00164 * \param module handle to the module that owns this translator 00165 * \return 0 on success, -1 on failure 00166 */ 00167 int __ast_register_translator(struct ast_translator *t, struct ast_module *module); 00168 #define ast_register_translator(t) __ast_register_translator(t, ast_module_info->self) 00169 00170 /*! 00171 * \brief Unregister a translator 00172 * Unregisters the given tranlator 00173 * \param t translator to unregister 00174 * \return 0 on success, -1 on failure 00175 */ 00176 int ast_unregister_translator(struct ast_translator *t); 00177 00178 /*! 00179 * \brief Activate a previously deactivated translator 00180 * \param t translator to activate 00181 * \return nothing 00182 * 00183 * Enables the specified translator for use. 00184 */ 00185 void ast_translator_activate(struct ast_translator *t); 00186 00187 /*! 00188 * \brief Deactivate a translator 00189 * \param t translator to deactivate 00190 * \return nothing 00191 * 00192 * Disables the specified translator from being used. 00193 */ 00194 void ast_translator_deactivate(struct ast_translator *t); 00195 00196 /*! 00197 * \brief Chooses the best translation path 00198 * 00199 * Given a list of sources, and a designed destination format, which should 00200 * I choose? 00201 * \return Returns 0 on success, -1 if no path could be found. 00202 * \note Modifies dests and srcs in place 00203 */ 00204 int ast_translator_best_choice(int *dsts, int *srcs); 00205 00206 /*! 00207 * \brief Builds a translator path 00208 * Build a path (possibly NULL) from source to dest 00209 * \param dest destination format 00210 * \param source source format 00211 * \return ast_trans_pvt on success, NULL on failure 00212 * */ 00213 struct ast_trans_pvt *ast_translator_build_path(int dest, int source); 00214 00215 /*! 00216 * \brief Frees a translator path 00217 * Frees the given translator path structure 00218 * \param tr translator path to get rid of 00219 */ 00220 void ast_translator_free_path(struct ast_trans_pvt *tr); 00221 00222 /*! 00223 * \brief translates one or more frames 00224 * Apply an input frame into the translator and receive zero or one output frames. Consume 00225 * determines whether the original frame should be freed 00226 * \param tr translator structure to use for translation 00227 * \param f frame to translate 00228 * \param consume Whether or not to free the original frame 00229 * \return an ast_frame of the new translation format on success, NULL on failure 00230 */ 00231 struct ast_frame *ast_translate(struct ast_trans_pvt *tr, struct ast_frame *f, int consume); 00232 00233 /*! 00234 * \brief Returns the number of steps required to convert from 'src' to 'dest'. 00235 * \param dest destination format 00236 * \param src source format 00237 * \return the number of translation steps required, or -1 if no path is available 00238 */ 00239 unsigned int ast_translate_path_steps(unsigned int dest, unsigned int src); 00240 00241 /*! 00242 * \brief Mask off unavailable formats from a format bitmask 00243 * \param dest possible destination formats 00244 * \param src source formats 00245 * \return the destination formats that are available in the source or translatable 00246 * 00247 * The result will include all formats from 'dest' that are either present 00248 * in 'src' or translatable from a format present in 'src'. 00249 * 00250 * Note that only a single audio format and a single video format can be 00251 * present in 'src', or the function will produce unexpected results. 00252 */ 00253 unsigned int ast_translate_available_formats(unsigned int dest, unsigned int src); 00254 00255 /*! 00256 * \brief Hint that a frame from a translator has been freed 00257 * 00258 * This is sort of a hack. This function gets called when ast_frame_free() gets 00259 * called on a frame that has the AST_FRFLAG_FROM_TRANSLATOR flag set. This is 00260 * because it is possible for a translation path to be destroyed while a frame 00261 * from a translator is still in use. Specifically, this happens if a masquerade 00262 * happens after a call to ast_read() but before the frame is done being processed, 00263 * since the frame processing is generally done without the channel lock held. 00264 * 00265 * \return nothing 00266 */ 00267 void ast_translate_frame_freed(struct ast_frame *fr); 00268 00269 #if defined(__cplusplus) || defined(c_plusplus) 00270 } 00271 #endif 00272 00273 #endif /* _ASTERISK_TRANSLATE_H */