lqt_codecinfo.h

这个库实现了录象功能

/*******************************************************************************
 lqt_codecinfo.h

 libquicktime - A library for reading and writing quicktime/avi/mp4 files.
 http://libquicktime.sourceforge.net

 Copyright (C) 2002 Heroine Virtual Ltd.
 Copyright (C) 2002-2007 Members of the libquicktime project.

 This library is free software; you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by the Free
 Software Foundation; either version 2.1 of the License, or (at your option)
 any later version.

 This library is distributed in the hope that it will be useful, but WITHOUT
 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
 details.

 You should have received a copy of the GNU Lesser General Public License along
 with this library; if not, write to the Free Software Foundation, Inc., 51
 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*******************************************************************************/

/*
 *   Codec info structure for libquicktime
 *   (first approximation)
 */

/* Type of a codec parameter */

#ifndef _LQT_CODEC_INFO_H_
#define _LQT_CODEC_INFO_H_

#pragma GCC visibility push(default)

#include <inttypes.h>



#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/**
   \defgroup codec_registry Codec registry
   \brief Informations about installed codecs

   One of the goals when forking libquicktime was to have a modular structure.
   Codecs were moved to plugins and were compiled according to the dependencies
   found by the configure script. As a result, a mechanism became necessary for
   finding informations about available codecs at runtime, their properties, supported
   parameters etc.

   The codec parameters are defined in a way that GUI configuration dialogs can be
   built at runtime. An example for this is the libquicktime_config utility.

   Libquicktime saves data of the codecs in the file .libquicktime_codecs in your
   home directory. This saves the long time needed for opening each codec module
   to see what's inside. The codec registry can be configured with the libquicktime_config
   program.
*/


/**
   \defgroup codec_parameters Structures describing codec parameters
   \ingroup codec_registry
   \brief Informations about supported codec parameters
*/
  
/**
   \ingroup codec_parameters
   \brief Parameter types

   These describe the datatypes of a parameter.
 */

typedef enum
  {
    LQT_PARAMETER_INT,     /*!< Integer */
    LQT_PARAMETER_FLOAT,   /*!< Float */
    LQT_PARAMETER_STRING,  /*!< String  */
    LQT_PARAMETER_STRINGLIST, /*!< String with fixed set of options */
    /* This dummy type is used to separate sections (real_name will be on tab-label) */
    LQT_PARAMETER_SECTION, /*!< Dummy type to group parameters into sections. */
  } lqt_parameter_type_t;

/**
   \ingroup codec_parameters
   \brief Union for holding parameter values

 */

typedef union
  {
  int val_int; /*!< For integer parameters */
  char * val_string; /*!< For string parameters */
  float val_float; /*!< For floating point parameters */
  } lqt_parameter_value_t;

/** \ingroup codec_parameters
 *  \brief Structure describing a parameter
 *
 * This completely describes a parameter. Bool parameters will have the type
 * \ref LQT_PARAMETER_INT , val_min = 0 and val_max = 1.
 */

typedef struct
  {
  char * name;   /*!< Parameter name to be passed to on of the parameter setting functions */

  char * real_name; /*!< More human readable name for configuration dialogs */
  
  lqt_parameter_type_t type; /*!< Datatype */
  
  lqt_parameter_value_t val_default; /*!< Default value */
  
  /*
   *   Minimum and maximum values:
   *   These are only valid for numeric types and if val_min < val_max
   */
  
  lqt_parameter_value_t val_min; /*!< Minimum value for integer or float parameter */
  lqt_parameter_value_t val_max; /*!< Maximum value for integer or float parameter */

  int num_digits; /*!< Number of digits for floating point parameters */
  
  /*
   *  Possible options (only valid for LQT_STRINGLIST)
   */
  
  int num_stringlist_options; /*!< Number of options for \ref LQT_PARAMETER_STRINGLIST */
  char ** stringlist_options; /*!< Options for \ref LQT_PARAMETER_STRINGLIST */
  char ** stringlist_labels;  /*!< Labels for \ref LQT_PARAMETER_STRINGLIST */

  char * help_string; /*!< Detailed help about the parameter */
  
  } lqt_parameter_info_t;

/** \ingroup codec_registry
    \brief Type of a codec (Audio or video)
*/

typedef enum
  {
    LQT_CODEC_AUDIO,
    LQT_CODEC_VIDEO
  } lqt_codec_type;

/** \ingroup codec_registry
    \brief Direction of the codec
*/
  
typedef enum
  {
    LQT_DIRECTION_ENCODE,
    LQT_DIRECTION_DECODE,
    LQT_DIRECTION_BOTH
  } lqt_codec_direction;

/** \ingroup codec_registry
    \brief Structure describing a codec
*/
  
typedef struct lqt_codec_info_s
  {
  int compatibility_flags; /*!< Compatibility flags (not used right now) */

  /* These are set by the plugins */
  
  char * name;               /*!< Name of the codec (used internally) */
  char * long_name;          /*!< More human readable name of the codec         */
  char * description;        /*!< Description                    */

  lqt_codec_type type;           /*!< Type (audio or video) */
  lqt_codec_direction direction; /*!< Direction (encode, decode or both) */
  
  int num_fourccs;      /*!< Number of fourccs (Four character codes), this codec can handle */
  char ** fourccs;      /*!< Fourccs this codec can handle */

  int num_wav_ids; /*!< Number of M$ wav ids, this codec can handle */
  int * wav_ids;   /*!< Wav ids, this codec can handle (for AVI only) */
  
  
  int num_encoding_parameters; /*!< Number of encoding parameters */
  lqt_parameter_info_t * encoding_parameters; /*!< Encoding parameters */

  int num_decoding_parameters; /*!< Number of decoding parameters */
  lqt_parameter_info_t * decoding_parameters; /*!< Decoding parameters */

  /* The following members are set by libquicktime      */
  
  char * module_filename;    /*!< Filename of the module */
  int module_index;          /*!< Index inside the module */
  
  uint32_t file_time;        /*!< File modification time of the module */

  char * gettext_domain;     /*!< First argument to bindtextdomain(). Must be set only for externally packaged codecs */
  char * gettext_directory;  /*!< Second argument to bindtextdomain(). Must be set only for externally packaged codecs */
  
  struct lqt_codec_info_s * next;   /*!< For chaining (used internally only) */
  } lqt_codec_info_t;


/* Global Entry points */

/** \ingroup codec_registry
    \brief Initialize the codec registry

    Under normal circumstances, you never need to call this function, since the
    registry is always initialized on demand.
 */

void lqt_registry_init();

/** \ingroup codec_registry
 *  \brief Destroy the codec registry
 * 
 *   This frees memory for the whole codec database.
 *   It is normally called automatically, but you will need to call
 *   it exclicitely, if you want to reinitialize the codec registry at runtime
 */

void lqt_registry_destroy();

/* \ingroup codec_registry
 *
 * Save the registry file $HOME/.libquicktime_codecs.
 * Under normal circumstances, you never need to call this function
 */

void lqt_registry_write();


/******************************************************
 *  Non thread save functions for querying the
 *  codec registry. Suitable for single threaded