format.h

Go to the documentation of this file.

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2010, Digium, Inc.
 *
 * David Vossel <dvossel@digium.com>
 *
 * 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 Format API
 *
 * \author David Vossel <dvossel@digium.com>
 */

#ifndef _AST_FORMAT_H_
#define _AST_FORMAT_H_

#include "asterisk/astobj2.h"
#include "asterisk/silk.h"
#include "asterisk/celt.h"
#define AST_FORMAT_ATTR_SIZE 128
#define AST_FORMAT_INC 100000

/*! This is the value that ends a var list of format attribute
 * key value pairs. */
#define AST_FORMAT_ATTR_END -1

/* \brief Format Categories*/
enum ast_format_type {
   AST_FORMAT_TYPE_AUDIO = 1 * AST_FORMAT_INC,
   AST_FORMAT_TYPE_VIDEO = 2 * AST_FORMAT_INC,
   AST_FORMAT_TYPE_IMAGE = 3 * AST_FORMAT_INC,
   AST_FORMAT_TYPE_TEXT  = 4 * AST_FORMAT_INC,
};

enum ast_format_id {
   /*! G.723.1 compression */
   AST_FORMAT_G723_1           = 1 + AST_FORMAT_TYPE_AUDIO,
   /*! GSM compression */
   AST_FORMAT_GSM              = 2 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw mu-law data (G.711) */
   AST_FORMAT_ULAW             = 3 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw A-law data (G.711) */
   AST_FORMAT_ALAW             = 4 + AST_FORMAT_TYPE_AUDIO,
   /*! ADPCM (G.726, 32kbps, AAL2 codeword packing) */
   AST_FORMAT_G726_AAL2        = 5 + AST_FORMAT_TYPE_AUDIO,
   /*! ADPCM (IMA) */
   AST_FORMAT_ADPCM            = 6 + AST_FORMAT_TYPE_AUDIO,
   /*! LPC10, 180 samples/frame */
   AST_FORMAT_LPC10            = 7 + AST_FORMAT_TYPE_AUDIO,
   /*! G.729A audio */
   AST_FORMAT_G729A            = 8 + AST_FORMAT_TYPE_AUDIO,
   /*! SpeeX Free Compression */
   AST_FORMAT_SPEEX            = 9 + AST_FORMAT_TYPE_AUDIO,
   /*! iLBC Free Compression */
   AST_FORMAT_ILBC             = 10 + AST_FORMAT_TYPE_AUDIO,
   /*! ADPCM (G.726, 32kbps, RFC3551 codeword packing) */
   AST_FORMAT_G726             = 11 + AST_FORMAT_TYPE_AUDIO,
   /*! G.722 */
   AST_FORMAT_G722             = 12 + AST_FORMAT_TYPE_AUDIO,
   /*! G.722.1 (also known as Siren7, 32kbps assumed) */
   AST_FORMAT_SIREN7           = 13 + AST_FORMAT_TYPE_AUDIO,
   /*! G.722.1 Annex C (also known as Siren14, 48kbps assumed) */
   AST_FORMAT_SIREN14          = 14 + AST_FORMAT_TYPE_AUDIO,
   /*! G.719 (64 kbps assumed) */
   AST_FORMAT_G719             = 15 + AST_FORMAT_TYPE_AUDIO,
   /*! SpeeX Wideband (16kHz) Free Compression */
   AST_FORMAT_SPEEX16          = 16 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw mu-law data (G.711) */
   AST_FORMAT_TESTLAW          = 17 + AST_FORMAT_TYPE_AUDIO,
   /*! SILK format */
   AST_FORMAT_SILK             = 18 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (8000 Hz) PCM */
   AST_FORMAT_SLINEAR          = 19 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (12000 Hz) PCM */
   AST_FORMAT_SLINEAR12        = 20 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (16000 Hz) PCM */
   AST_FORMAT_SLINEAR16        = 21 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (24000 Hz) PCM */
   AST_FORMAT_SLINEAR24        = 22 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (32000 Hz) PCM */
   AST_FORMAT_SLINEAR32        = 23 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (44100 Hz) PCM just because we can. */
   AST_FORMAT_SLINEAR44        = 24 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (48000 Hz) PCM */
   AST_FORMAT_SLINEAR48        = 25 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (96000 Hz) PCM */
   AST_FORMAT_SLINEAR96        = 26 + AST_FORMAT_TYPE_AUDIO,
   /*! Raw 16-bit Signed Linear (192000 Hz) PCM.  maybe we're taking this too far. */
   AST_FORMAT_SLINEAR192       = 27 + AST_FORMAT_TYPE_AUDIO,
   AST_FORMAT_SPEEX32          = 28 + AST_FORMAT_TYPE_AUDIO,
   AST_FORMAT_CELT             = 29 + AST_FORMAT_TYPE_AUDIO,

   /*! H.261 Video */
   AST_FORMAT_H261             = 1 + AST_FORMAT_TYPE_VIDEO,
   /*! H.263 Video */
   AST_FORMAT_H263             = 2 + AST_FORMAT_TYPE_VIDEO,
   /*! H.263+ Video */
   AST_FORMAT_H263_PLUS        = 3 + AST_FORMAT_TYPE_VIDEO,
   /*! H.264 Video */
   AST_FORMAT_H264             = 4 + AST_FORMAT_TYPE_VIDEO,
   /*! MPEG4 Video */
   AST_FORMAT_MP4_VIDEO        = 5 + AST_FORMAT_TYPE_VIDEO,

   /*! JPEG Images */
   AST_FORMAT_JPEG             = 1 + AST_FORMAT_TYPE_IMAGE,
   /*! PNG Images */
   AST_FORMAT_PNG              = 2 + AST_FORMAT_TYPE_IMAGE,

   /*! T.140 RED Text format RFC 4103 */
   AST_FORMAT_T140RED          = 1 + AST_FORMAT_TYPE_TEXT,
   /*! T.140 Text format - ITU T.140, RFC 4103 */
   AST_FORMAT_T140             = 2 + AST_FORMAT_TYPE_TEXT,
};

/*! Determine what type of media a ast_format_id is. */
#define AST_FORMAT_GET_TYPE(id) (((int) (id / AST_FORMAT_INC)) * AST_FORMAT_INC)


/*! \brief This structure contains the buffer used for format attributes */
struct ast_format_attr {
   /*! The buffer formats can use to represent attributes */
   uint8_t format_attr[AST_FORMAT_ATTR_SIZE];
   /*! If a format's payload needs to pass through that a new marker is required
    * for RTP, this variable will be set. */
   uint8_t rtp_marker_bit;
};

/*! \brief Represents a media format within Asterisk. */
struct ast_format {
   /*! The unique id representing this format from all the other formats. */
   enum ast_format_id id;
   /*!  Attribute structure used to associate attributes with a format. */
   struct ast_format_attr fattr;
};

enum ast_format_cmp_res {
   /*! structure 1 is identical to structure 2. */
   AST_FORMAT_CMP_EQUAL = 0,
   /*! structure 1 contains elements not in structure 2. */
   AST_FORMAT_CMP_NOT_EQUAL,
   /*! structure 1 is a proper subset of the elements in structure 2.*/
   AST_FORMAT_CMP_SUBSET,
};

/*! \brief Definition of supported media formats (codecs) */
struct ast_format_list {
   struct ast_format format; /*!< The unique format. */
   char name[64]; /*!< short name */
   unsigned int samplespersecond; /*!< Number of samples per second (8000/16000) */
   char desc[128];   /*!< Description */
   int fr_len; /*!< Single frame length in bytes */
   int min_ms; /*!< Min value */
   int max_ms; /*!< Max value */
   int inc_ms; /*!< Increment */
   int def_ms; /*!< Default value */
   unsigned int flags;  /*!< Smoother flags */
   int cur_ms; /*!< Current value */
   int custom_entry;
};

/*! \brief A format must register an attribute interface if it requires the use of the format attributes void pointer */
struct ast_format_attr_interface {
   /*! format type */
   enum ast_format_id id;

   /*! \brief Determine if format_attr 1 is a subset of format_attr 2.
    *
    * \retval ast_format_cmp_res representing the result of comparing fattr1 and fattr2.
    */
   enum ast_format_cmp_res (* const format_attr_cmp)(const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2);

   /*! \brief Get joint attributes of same format type if they exist.
    *
    * \retval 0 if joint attributes exist
    * \retval -1 if no joint attributes are present
    */
   int (* const format_attr_get_joint)(const struct ast_format_attr *fattr1, const struct ast_format_attr *fattr2, struct ast_format_attr *result);

   /*! \brief Set format capabilities from a list of key value pairs ending with AST_FORMAT_ATTR_END.
    * \note This function does not need to call va_end of the va_list. */
   void (* const format_attr_set)(struct ast_format_attr *format_attr, va_list ap);

   /*!
    * \brief Find out if format capabilities in va_list are in format.
    * \note This function does not need to call va_end of the va_list.
    *
    * \note This function is optional.  In many cases the format_attr_cmp
    * function can be used to derive these results.  If it is possible
    * that some format attributes have no bearing on the equality of two formats, this
    * function must exist.
    *
    * \retval 0 if all attributes exist
    * \retval -1 if any of the attributes not present
    */
   int (* const format_attr_isset)(const struct ast_format_attr *format_attr, va_list ap);

   /*
    * \brief Return a value for a specific format key.   Return that value in the void pointer.
    *
    * \note It is not expected that all key value pairs can be returned, but those that can should
    * be documented as such.
    *
    * \note This function is optional if key value pairs are not allowed to be accessed.  This
    * will result in -1 always being returned.
    *
    * \retval 0 Success, value was found and copied into void pointer.
    * \retval -1 failure, Value was either not found, or not allowed to be accessed.
    */
   int (* const format_attr_get_val)(const struct ast_format_attr *format_attr, int key, void *val);
};

/*!
 * \brief This function is used to set an ast_format object to represent a media format
 * with optional format attributes represented by format specific key value pairs.
 *
 * \param format to set
 * \param id, format id to set on format
 * \param set_attributes, are there attributes to set on this format. 0 == false, 1 == True.
 * \param var list of attribute key value pairs, must end with AST_FORMAT_ATTR_END;
 *
 * \details Example usage.
 * ast_format_set(format, AST_FORMAT_ULAW, 0); // no capability attributes are needed for ULAW
 *
 * ast_format_set(format, AST_FORMAT_SILK, 1, // SILK has capability attributes.
 *   AST_FORMAT_SILK_ATTR_RATE, 24000,
 *   AST_FORMAT_SILK_ATTR_RATE, 16000,
 *   AST_FORMAT_SILK_ATTR_RATE, 12000,
 *   AST_FORMAT_SILK_ATTR_RATE, 8000,
 *   AST_FORMAT_ATTR_END);
 *
 * \note This function will initialize the ast_format structure.
 *
 * \return Pointer to ast_format object, same pointer that is passed in
 * by the first argument.
 */
struct ast_format *ast_format_set(struct ast_format *format, enum ast_format_id id, int set_attributes, ... );

/*!
 * \brief After ast_format_set has been used on a function, this function can be used to
 * set additional format attributes to the structure.
 *
 * \param format to set
 * \param var list of attribute key value pairs, must end with AST_FORMAT_ATTR_END;
 *
 * \details Example usage.
 * ast_format_set(format, AST_FORMAT_SILK, 0);
 * ast_format_append(format, // SILK has capability attributes.
 *   AST_FORMAT_SILK_ATTR_RATE, 24000,
 *   AST_FORMAT_SILK_ATTR_RATE, 16000,
 *   AST_FORMAT_SILK_ATTR_RATE, 12000,
 *   AST_FORMAT_SILK_ATTR_RATE, 8000,
 *   AST_FORMAT_ATTR_END);
 *
 * \return Pointer to ast_format object, same pointer that is passed in
 * by the first argument.
 */
struct ast_format *ast_format_append(struct ast_format *format, ... );

/*!
 * \brief Clears the format stucture.
 */
void ast_format_clear(struct ast_format *format);

/*!
 * \brief This function is used to set an ast_format object to represent a media format
 * with optional capability attributes represented by format specific key value pairs.
 *
 * \details Example usage. Is this SILK format capable of 8khz
 * is_8khz = ast_format_isset(format, AST_FORMAT_SILK_CAP_RATE, 8000);
 *
 * \return 0, The format key value pairs are within the capabilities defined in this structure.
 * \return -1, The format key value pairs are _NOT_ within the capabilities of this structure.
 */
int ast_format_isset(const struct ast_format *format, ... );

/*!
 * \brief Get a value from a format containing attributes.
 * \note The key represents the format attribute to be retrieved, and the void pointer
 * is to the structure that value will be stored in.  It must be known what structure a
 * key represents.
 *
 * \retval 0, success
 * \retval -1, failure
 */
int ast_format_get_value(const struct ast_format *format, int key, void *value);

/*!
 * \brief Compare ast_formats structures
 *
 * \retval ast_format_cmp_res representing the result of comparing format1 and format2.
 */
enum ast_format_cmp_res ast_format_cmp(const struct ast_format *format1, const struct ast_format *format2);

/*!
 * \brief Find joint format attributes of two ast_format
 * structures containing the same uid and return the intersection in the
 * result structure.
 *
 * retval 0, joint attribute capabilities exist.
 * retval -1, no joint attribute capabilities exist.
 */
int ast_format_joint(const struct ast_format *format1, const struct ast_format *format2, struct ast_format *result);

/*!
 * \brief copy format src into format dst.
 */
void ast_format_copy(struct ast_format *dst, const struct ast_format *src);

/*!
 * \brief Set the rtp mark value on the format to indicate to the interface
 * writing this format's payload that a new RTP marker is necessary.
 */
void ast_format_set_video_mark(struct ast_format *format);

/*!
 * \brief Determine of the marker bit is set or not on this format.
 *
 * \retval 1, true
 * \retval 0, false
 */
int ast_format_get_video_mark(const struct ast_format *format);

/*!
 * \brief ast_format to old bitfield format represenatation
 *
 * \note This is only to be used for IAX2 compatibility 
 *
 * \retval iax2 representation of ast_format
 * \retval 0, if no representation existis for iax2
 */
uint64_t ast_format_to_old_bitfield(const struct ast_format *format);

/*!
 * \brief ast_format_id to old bitfield format represenatation
 *
 */
uint64_t ast_format_id_to_old_bitfield(enum ast_format_id id);

/*!
 * \brief convert old bitfield format to ast_format represenatation
 * \note This is only to be used for IAX2 compatibility 
 *
 * \retval on success, pointer to the dst format in the input parameters
 * \retval on failure, NULL
 */
struct ast_format *ast_format_from_old_bitfield(struct ast_format *dst, uint64_t src);

/*!
 * \brief convert old bitfield format to ast_format_id value
 */
enum ast_format_id ast_format_id_from_old_bitfield(uint64_t src);

/*!
 * \brief Retrieve the global format list in a read only array.
 * \note ast_format_list_destroy must be called on every format
 * list retrieved from this function.
 */
const struct ast_format_list *ast_format_list_get(size_t *size);

/*!
 * \brief Destroy an ast_format_list gotten from ast_format_list_get()
 */
const struct ast_format_list *ast_format_list_destroy(const struct ast_format_list *list);

/*! \brief Get the name of a format
 * \param format id of format
 * \return A static string containing the name of the format or "unknown" if unknown.
 */
const char* ast_getformatname(const struct ast_format *format);

/*! \brief Returns a string containing all formats pertaining to an format id.
 * \param buf a buffer for the output string
 * \param size size of buf (bytes)
 * \param format id.
 * \return The return value is buf.
 */
char* ast_getformatname_multiple_byid(char *buf, size_t size, enum ast_format_id id);

/*!
 * \brief Gets a format from a name.
 * \param name string of format
 * \param format structure to return the format in.
 * \return This returns the format pointer given to it on success and NULL on failure
 */
struct ast_format *ast_getformatbyname(const char *name, struct ast_format *format);

/*!
 * \brief Get a name from a format 
 * \param format to get name of
 * \return This returns a static string identifying the format on success, 0 on error.
 */
const char *ast_codec2str(struct ast_format *format);

/*!
 * \brief Get the sample rate for a given format.
 */
int ast_format_rate(const struct ast_format *format);

/*!
 * \brief register ast_format_attr_interface with core.
 *
 * \retval 0 success
 * \retval -1 failure
 */
int ast_format_attr_reg_interface(const struct ast_format_attr_interface *interface);

/*!
 * \brief unregister format_attr interface with core.
 *
 * \retval 0 success
 * \retval -1 failure
 */
int ast_format_attr_unreg_interface(const struct ast_format_attr_interface *interface);

/*!
 * \brief Determine if a format is 16bit signed linear of any sample rate. 
 */
int ast_format_is_slinear(const struct ast_format *format);

/*!
 * \brief Get the best slinear format id for a given sample rate
 */
enum ast_format_id ast_format_slin_by_rate(unsigned int rate);
#endif /* _AST_FORMAT_H */