text: /* $Id: wave.h 3553 2011-05-05 06:14:19Z nanang $ */
  /* 
   * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
   * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program 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 General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
   */
  #ifndef __PJMEDIA_WAVE_H__
  #define __PJMEDIA_WAVE_H__
  
  
  /**
   * @file wave.h
   * @brief WAVE file manipulation.
   */
  #include <ZadarmaPJSIP/pjmedia/types.h>
  
  /**
   * @defgroup PJMEDIA_FILE_FORMAT File Formats
   * @brief Supported file formats
   */
  
  
  /**
   * @defgroup PJMEDIA_WAVE WAVE Header
   * @ingroup PJMEDIA_FILE_FORMAT
   * @brief Representation of RIFF/WAVE file format
   * @{
   *
   * This the the low level representation of RIFF/WAVE file format. For
   * higher abstraction, please see \ref PJMEDIA_FILE_PLAY and 
   * \ref PJMEDIA_FILE_REC.
   */
  
  
  PJ_BEGIN_DECL
  
  /**
   * Standard RIFF tag to identify RIFF file format in the WAVE header.
   */
  #define PJMEDIA_RIFF_TAG	('F'<<24|'F'<<16|'I'<<8|'R')
  
  /**
   * Standard WAVE tag to identify WAVE header.
   */
  #define PJMEDIA_WAVE_TAG	('E'<<24|'V'<<16|'A'<<8|'W')
  
  /**
   * Standard FMT tag to identify format chunks.
   */
  #define PJMEDIA_FMT_TAG		(' '<<24|'t'<<16|'m'<<8|'f')
  
  /**
   * Standard DATA tag to identify data chunks.
   */
  #define PJMEDIA_DATA_TAG	('a'<<24|'t'<<16|'a'<<8|'d')
  
  /**
   * Standard FACT tag to identify fact chunks.
   */
  #define PJMEDIA_FACT_TAG	('t'<<24|'c'<<16|'a'<<8|'f')
  
  
  /**
   * Enumeration of format compression tag.
   */
  typedef enum {
      PJMEDIA_WAVE_FMT_TAG_PCM	= 1,
      PJMEDIA_WAVE_FMT_TAG_ALAW	= 6,
      PJMEDIA_WAVE_FMT_TAG_ULAW	= 7
  } pjmedia_wave_fmt_tag;
  
  
  /**
   * This file describes the simpler/canonical version of a WAVE file.
   * It does not support the full RIFF format specification.
   */
  #pragma pack(2)
  struct pjmedia_wave_hdr
  {
      /** This structure describes RIFF WAVE file header */
      struct {
  	pj_uint32_t riff;		/**< "RIFF" ASCII tag.		*/
  	pj_uint32_t file_len;		/**< File length minus 8 bytes	*/
  	pj_uint32_t wave;		/**< "WAVE" ASCII tag.		*/
      } riff_hdr;
  
      /** This structure describes format chunks/header  */
      struct {
  	pj_uint32_t fmt;		/**< "fmt " ASCII tag.		*/
  	pj_uint32_t len;		/**< 16 for PCM.		*/
  	pj_uint16_t fmt_tag;		/**< 1 for PCM			*/
  	pj_uint16_t nchan;		/**< Number of channels.	*/
  	pj_uint32_t sample_rate;	/**< Sampling rate.		*/
  	pj_uint32_t bytes_per_sec;	/**< Average bytes per second.	*/
  	pj_uint16_t block_align;	/**< nchannels * bits / 8	*/
  	pj_uint16_t bits_per_sample;	/**< Bits per sample.		*/
      } fmt_hdr;
  
      /** The data header preceeds the actual data in the file. */
      struct {
  	pj_uint32_t data;		/**< "data" ASCII tag.		*/
  	pj_uint32_t len;		/**< Data length.		*/
      } data_hdr;
  };
  #pragma pack()
  
  /**
   * @see pjmedia_wave_hdr
   */
  typedef struct pjmedia_wave_hdr pjmedia_wave_hdr;
  
  /**
   * This structure describes generic RIFF subchunk header.
   */
  typedef struct pjmedia_wave_subchunk
  {
      pj_uint32_t	    id;			/**< Subchunk ASCII tag.	    */
      pj_uint32_t	    len;		/**< Length following this field    */
  } pjmedia_wave_subchunk;
  
  
  /**
   * Normalize subchunk header from little endian (the representation of
   * RIFF file) into host's endian.
   */
  #if defined(PJ_IS_BIG_ENDIAN) && PJ_IS_BIG_ENDIAN!=0
  #   define PJMEDIA_WAVE_NORMALIZE_SUBCHUNK(ch)  \
  	    do { \
  		(ch)->id = pj_swap32((ch)->id); \
  		(ch)->len = pj_swap32((ch)->len); \
  	    } while (0)
  #else
  #   define PJMEDIA_WAVE_NORMALIZE_SUBCHUNK(ch)
  #endif
  
  
  /**
   * On big-endian hosts, this function swaps the byte order of the values
   * in the WAVE header fields. On little-endian hosts, this function does 
   * nothing.
   *
   * Application SHOULD call this function after reading the WAVE header
   * chunks from a file.
   *
   * @param hdr	    The WAVE header.
   */
  PJ_DECL(void) pjmedia_wave_hdr_file_to_host( pjmedia_wave_hdr *hdr );
  
  
  /**
   * On big-endian hosts, this function swaps the byte order of the values
   * in the WAVE header fields. On little-endian hosts, this function does 
   * nothing.
   *
   * Application SHOULD call this function before writing the WAVE header
   * to a file.
   *
   * @param hdr	    The WAVE header.
   */
  PJ_DECL(void) pjmedia_wave_hdr_host_to_file( pjmedia_wave_hdr *hdr );
  
  
  PJ_END_DECL
  
  /**
   * @}
   */
  
  
  #endif	/* __PJMEDIA_WAVE_H__ */
  
  