speex_header.h

00001 /* Copyright (C) 2002 Jean-Marc Valin */
00002 /**
00003    @file speex_header.h
00004    @brief Describes the Speex header
00005 */
00006 /*
00007    Redistribution and use in source and binary forms, with or without
00008    modification, are permitted provided that the following conditions
00009    are met:
00010    
00011    - Redistributions of source code must retain the above copyright
00012    notice, this list of conditions and the following disclaimer.
00013    
00014    - Redistributions in binary form must reproduce the above copyright
00015    notice, this list of conditions and the following disclaimer in the
00016    documentation and/or other materials provided with the distribution.
00017    
00018    - Neither the name of the Xiph.org Foundation nor the names of its
00019    contributors may be used to endorse or promote products derived from
00020    this software without specific prior written permission.
00021    
00022    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00023    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00024    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00025    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
00026    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00027    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00028    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00029    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00030    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00031    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00032    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00033 
00034 */
00035 
00036 
00037 #ifndef SPEEX_HEADER_H
00038 #define SPEEX_HEADER_H
00039 /** @defgroup SpeexHeader SpeexHeader: Makes it easy to write/parse an Ogg/Speex header
00040  *  This is the Speex header for the Ogg encapsulation. You don't need that if you just use RTP.
00041  *  @{
00042  */
00043 
00044 #include "speex/speex_types.h"
00045 
00046 #ifdef __cplusplus
00047 extern "C" {
00048 #endif
00049 
00050 struct SpeexMode;
00051 
00052 /** Length of the Speex header identifier */
00053 #define SPEEX_HEADER_STRING_LENGTH 8
00054 
00055 /** Maximum number of characters for encoding the Speex version number in the header */
00056 #define SPEEX_HEADER_VERSION_LENGTH 20
00057 
00058 /** Speex header info for file-based formats */
00059 typedef struct SpeexHeader {
00060    char speex_string[SPEEX_HEADER_STRING_LENGTH];   /**< Identifies a Speex bit-stream, always set to "Speex   " */
00061    char speex_version[SPEEX_HEADER_VERSION_LENGTH]; /**< Speex version */ 
00062    spx_int32_t speex_version_id;       /**< Version for Speex (for checking compatibility) */
00063    spx_int32_t header_size;            /**< Total size of the header ( sizeof(SpeexHeader) ) */
00064    spx_int32_t rate;                   /**< Sampling rate used */
00065    spx_int32_t mode;                   /**< Mode used (0 for narrowband, 1 for wideband) */
00066    spx_int32_t mode_bitstream_version; /**< Version ID of the bit-stream */
00067    spx_int32_t nb_channels;            /**< Number of channels encoded */
00068    spx_int32_t bitrate;                /**< Bit-rate used */
00069    spx_int32_t frame_size;             /**< Size of frames */
00070    spx_int32_t vbr;                    /**< 1 for a VBR encoding, 0 otherwise */
00071    spx_int32_t frames_per_packet;      /**< Number of frames stored per Ogg packet */
00072    spx_int32_t extra_headers;          /**< Number of additional headers after the comments */
00073    spx_int32_t reserved1;              /**< Reserved for future use, must be zero */
00074    spx_int32_t reserved2;              /**< Reserved for future use, must be zero */
00075 } SpeexHeader;
00076 
00077 /** Initializes a SpeexHeader using basic information */
00078 void speex_init_header(SpeexHeader *header, int rate, int nb_channels, const struct SpeexMode *m);
00079 
00080 /** Creates the header packet from the header itself (mostly involves endianness conversion) */
00081 char *speex_header_to_packet(SpeexHeader *header, int *size);
00082 
00083 /** Creates a SpeexHeader from a packet */
00084 SpeexHeader *speex_packet_to_header(char *packet, int size);
00085 
00086 #ifdef __cplusplus
00087 }
00088 #endif
00089 
00090 /** @} */
00091 #endif