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 int datalen; 00142 void *pvt; /*!< more private data, if any */ 00143 char *outbuf; /*!< the useful portion of the buffer */ 00144 plc_state_t *plc; /*!< optional plc pointer */ 00145 struct ast_trans_pvt *next; /*!< next in translator chain */ 00146 struct timeval nextin; 00147 struct timeval nextout; 00148 }; 00149 00150 /*! \brief generic frameout function */ 00151 struct ast_frame *ast_trans_frameout(struct ast_trans_pvt *pvt, 00152 int datalen, int samples); 00153 00154 struct ast_trans_pvt; 00155 00156 /*! 00157 * \brief Register a translator 00158 * This registers a codec translator with asterisk 00159 * \param t populated ast_translator structure 00160 * \param module handle to the module that owns this translator 00161 * \return 0 on success, -1 on failure 00162 */ 00163 int __ast_register_translator(struct ast_translator *t, struct ast_module *module); 00164 #define ast_register_translator(t) __ast_register_translator(t, ast_module_info->self) 00165 00166 /*! 00167 * \brief Unregister a translator 00168 * Unregisters the given tranlator 00169 * \param t translator to unregister 00170 * \return 0 on success, -1 on failure 00171 */ 00172 int ast_unregister_translator(struct ast_translator *t); 00173 00174 /*! 00175 * \brief Activate a previously deactivated translator 00176 * \param t translator to activate 00177 * \return nothing 00178 * 00179 * Enables the specified translator for use. 00180 */ 00181 void ast_translator_activate(struct ast_translator *t); 00182 00183 /*! 00184 * \brief Deactivate a translator 00185 * \param t translator to deactivate 00186 * \return nothing 00187 * 00188 * Disables the specified translator from being used. 00189 */ 00190 void ast_translator_deactivate(struct ast_translator *t); 00191 00192 /*! 00193 * \brief Chooses the best translation path 00194 * 00195 * Given a list of sources, and a designed destination format, which should 00196 * I choose? 00197 * \return Returns 0 on success, -1 if no path could be found. 00198 * \note Modifies dests and srcs in place 00199 */ 00200 int ast_translator_best_choice(int *dsts, int *srcs); 00201 00202 /*! 00203 * \brief Builds a translator path 00204 * Build a path (possibly NULL) from source to dest 00205 * \param dest destination format 00206 * \param source source format 00207 * \return ast_trans_pvt on success, NULL on failure 00208 * */ 00209 struct ast_trans_pvt *ast_translator_build_path(int dest, int source); 00210 00211 /*! 00212 * \brief Frees a translator path 00213 * Frees the given translator path structure 00214 * \param tr translator path to get rid of 00215 */ 00216 void ast_translator_free_path(struct ast_trans_pvt *tr); 00217 00218 /*! 00219 * \brief translates one or more frames 00220 * Apply an input frame into the translator and receive zero or one output frames. Consume 00221 * determines whether the original frame should be freed 00222 * \param tr translator structure to use for translation 00223 * \param f frame to translate 00224 * \param consume Whether or not to free the original frame 00225 * \return an ast_frame of the new translation format on success, NULL on failure 00226 */ 00227 struct ast_frame *ast_translate(struct ast_trans_pvt *tr, struct ast_frame *f, int consume); 00228 00229 /*! 00230 * \brief Returns the number of steps required to convert from 'src' to 'dest'. 00231 * \param dest destination format 00232 * \param src source format 00233 * \return the number of translation steps required, or -1 if no path is available 00234 */ 00235 unsigned int ast_translate_path_steps(unsigned int dest, unsigned int src); 00236 00237 /*! 00238 * \brief Mask off unavailable formats from a format bitmask 00239 * \param dest possible destination formats 00240 * \param src source formats 00241 * \return the destination formats that are available in the source or translatable 00242 * 00243 * The result will include all formats from 'dest' that are either present 00244 * in 'src' or translatable from a format present in 'src'. 00245 * 00246 * Note that only a single audio format and a single video format can be 00247 * present in 'src', or the function will produce unexpected results. 00248 */ 00249 unsigned int ast_translate_available_formats(unsigned int dest, unsigned int src); 00250 00251 #if defined(__cplusplus) || defined(c_plusplus) 00252 } 00253 #endif 00254 00255 #endif /* _ASTERISK_TRANSLATE_H */