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 /********************************************************************

  *                                                                  *

  * THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE.   *

  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *

  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *

  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *

  *                                                                  *

  * THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2009                *

  * by the Xiph.Org Foundation http://www.xiph.org/                  *

  *                                                                  *

  ********************************************************************

   function:

   last mod: $Id: theora.h,v 1.17 2003/12/06 18:06:19 arc Exp $

  ********************************************************************/

 #ifndef _O_THEORA_H_

 #define _O_THEORA_H_

 #ifdef __cplusplus

 extern "C"

 {

 #endif /* __cplusplus */

 #include <stddef.h>	/* for size_t */

 #include <ogg/ogg.h>

 /** \file

  * The libtheora pre-1.0 legacy C API.

  *

  * \ingroup oldfuncs

  *

  * \section intro Introduction

  *

  * This is the documentation for the libtheora legacy C API, declared in 

  * the theora.h header, which describes the old interface used before

  * the 1.0 release. This API was widely deployed for several years and

  * remains supported, but for new code we recommend the cleaner API 

  * declared in theoradec.h and theoraenc.h.

  *

  * libtheora is the reference implementation for

  * <a href="http://www.theora.org/">Theora</a>, a free video codec.

  * Theora is derived from On2's VP3 codec with improved integration with

  * Ogg multimedia formats by <a href="http://www.xiph.org/">Xiph.Org</a>.

  * 

  * \section overview Overview

  *

  * This library will both decode and encode theora packets to/from raw YUV 

  * frames.  In either case, the packets will most likely either come from or

  * need to be embedded in an Ogg stream.  Use 

  * <a href="http://xiph.org/ogg/">libogg</a> or 

  * <a href="http://www.annodex.net/software/liboggz/index.html">liboggz</a>

  * to extract/package these packets.

  *

  * \section decoding Decoding Process

  *

  * Decoding can be separated into the following steps:

  * -# initialise theora_info and theora_comment structures using 

  *    theora_info_init() and theora_comment_init():

  \verbatim

  theora_info     info;

  theora_comment  comment;

  theora_info_init(&info);

  theora_comment_init(&comment);

  \endverbatim

  * -# retrieve header packets from Ogg stream (there should be 3) and decode 

  *    into theora_info and theora_comment structures using 

  *    theora_decode_header().  See \ref identification for more information on 

  *    identifying which packets are theora packets.

  \verbatim

  int i;

  for (i = 0; i < 3; i++)

  {

    (get a theora packet "op" from the Ogg stream)

    theora_decode_header(&info, &comment, op);

  }

  \endverbatim

  * -# initialise the decoder based on the information retrieved into the

  *    theora_info struct by theora_decode_header().  You will need a 

  *    theora_state struct.

  \verbatim

  theora_state state;

  theora_decode_init(&state, &info);

  \endverbatim

  * -# pass in packets and retrieve decoded frames!  See the yuv_buffer 

  *    documentation for information on how to retrieve raw YUV data.

  \verbatim

  yuf_buffer buffer;

  while (last packet was not e_o_s) {

    (get a theora packet "op" from the Ogg stream)

    theora_decode_packetin(&state, op);

    theora_decode_YUVout(&state, &buffer);

  }

  \endverbatim

  *  

  *

  * \subsection identification Identifying Theora Packets

  *

  * All streams inside an Ogg file have a unique serial_no attached to the 

  * stream.  Typically, you will want to 

  *  - retrieve the serial_no for each b_o_s (beginning of stream) page 

  *    encountered within the Ogg file; 

  *  - test the first (only) packet on that page to determine if it is a theora 

  *    packet;

  *  - once you have found a theora b_o_s page then use the retrieved serial_no 

  *    to identify future packets belonging to the same theora stream.

  * 

  * Note that you \e cannot use theora_packet_isheader() to determine if a 

  * packet is a theora packet or not, as this function does not perform any

  * checking beyond whether a header bit is present.  Instead, use the

  * theora_decode_header() function and check the return value; or examine the

  * header bytes at the beginning of the Ogg page.

  */

 /** \defgroup oldfuncs Legacy pre-1.0 C API */

 /*  @{ */

 /**

  * A YUV buffer for passing uncompressed frames to and from the codec.

  * This holds a Y'CbCr frame in planar format. The CbCr planes can be

  * subsampled and have their own separate dimensions and row stride

  * offsets. Note that the strides may be negative in some 

  * configurations. For theora the width and height of the largest plane

  * must be a multiple of 16. The actual meaningful picture size and 

  * offset are stored in the theora_info structure; frames returned by

  * the decoder may need to be cropped for display.

  *

  * All samples are 8 bits. Within each plane samples are ordered by

  * row from the top of the frame to the bottom. Within each row samples

  * are ordered from left to right.

  *

  * During decode, the yuv_buffer struct is allocated by the user, but all

  * fields (including luma and chroma pointers) are filled by the library.  

  * These pointers address library-internal memory and their contents should 

  * not be modified.

  *

  * Conversely, during encode the user allocates the struct and fills out all

  * fields.  The user also manages the data addressed by the luma and chroma

  * pointers.  See the encoder_example.c and dump_video.c example files in

  * theora/examples/ for more information.

  */

 typedef struct {

     int   y_width;      /**< Width of the Y' luminance plane */

     int   y_height;     /**< Height of the luminance plane */

     int   y_stride;     /**< Offset in bytes between successive rows */

     int   uv_width;     /**< Width of the Cb and Cr chroma planes */

     int   uv_height;    /**< Height of the chroma planes */

     int   uv_stride;    /**< Offset between successive chroma rows */

     unsigned char *y;   /**< Pointer to start of luminance data */

     unsigned char *u;   /**< Pointer to start of Cb data */

     unsigned char *v;   /**< Pointer to start of Cr data */

 } yuv_buffer;

 /**

  * A Colorspace.

  */

 typedef enum {

   OC_CS_UNSPECIFIED,    /**< The colorspace is unknown or unspecified */

   OC_CS_ITU_REC_470M,   /**< This is the best option for 'NTSC' content */

   OC_CS_ITU_REC_470BG,  /**< This is the best option for 'PAL' content */

   OC_CS_NSPACES         /**< This marks the end of the defined colorspaces */

 } theora_colorspace;

 /**

  * A Chroma subsampling

  *

  * These enumerate the available chroma subsampling options supported

  * by the theora format. See Section 4.4 of the specification for

  * exact definitions.

  */

 typedef enum {

   OC_PF_420,    /**< Chroma subsampling by 2 in each direction (4:2:0) */

   OC_PF_RSVD,   /**< Reserved value */

   OC_PF_422,    /**< Horizonatal chroma subsampling by 2 (4:2:2) */

   OC_PF_444     /**< No chroma subsampling at all (4:4:4) */

 } theora_pixelformat;

 /**

  * Theora bitstream info.

  * Contains the basic playback parameters for a stream,

  * corresponding to the initial 'info' header packet.

  * 

  * Encoded theora frames must be a multiple of 16 in width and height.

  * To handle other frame sizes, a crop rectangle is specified in

  * frame_height and frame_width, offset_x and * offset_y. The offset

  * and size should still be a multiple of 2 to avoid chroma sampling

  * shifts. Offset values in this structure are measured from the

  * upper left of the image.

  *

  * Frame rate, in frames per second, is stored as a rational

  * fraction. Aspect ratio is also stored as a rational fraction, and

  * refers to the aspect ratio of the frame pixels, not of the

  * overall frame itself.

  * 

  * See <a href="http://svn.xiph.org/trunk/theora/examples/encoder_example.c">

  * examples/encoder_example.c</a> for usage examples of the

  * other paramters and good default settings for the encoder parameters.

  */

 typedef struct {

   ogg_uint32_t  width;		/**< encoded frame width  */

   ogg_uint32_t  height;		/**< encoded frame height */

   ogg_uint32_t  frame_width;	/**< display frame width  */

   ogg_uint32_t  frame_height;	/**< display frame height */

   ogg_uint32_t  offset_x;	/**< horizontal offset of the displayed frame */

   ogg_uint32_t  offset_y;	/**< vertical offset of the displayed frame */

   ogg_uint32_t  fps_numerator;	    /**< frame rate numerator **/

   ogg_uint32_t  fps_denominator;    /**< frame rate denominator **/

   ogg_uint32_t  aspect_numerator;   /**< pixel aspect ratio numerator */

   ogg_uint32_t  aspect_denominator; /**< pixel aspect ratio denominator */

   theora_colorspace colorspace;	    /**< colorspace */

   int           target_bitrate;	    /**< nominal bitrate in bits per second */

   int           quality;  /**< Nominal quality setting, 0-63 */

   int           quick_p;  /**< Quick encode/decode */

   /* decode only */

   unsigned char version_major;

   unsigned char version_minor;

   unsigned char version_subminor;

   void *codec_setup;

   /* encode only */

   int           dropframes_p;

   int           keyframe_auto_p;

   ogg_uint32_t  keyframe_frequency;

   ogg_uint32_t  keyframe_frequency_force;  /* also used for decode init to

                                               get granpos shift correct */

   ogg_uint32_t  keyframe_data_target_bitrate;

   ogg_int32_t   keyframe_auto_threshold;

   ogg_uint32_t  keyframe_mindistance;

   ogg_int32_t   noise_sensitivity;

   ogg_int32_t   sharpness;

   theora_pixelformat pixelformat;	/**< chroma subsampling mode to expect */

 } theora_info;

 /** Codec internal state and context.

  */

 typedef struct{

   theora_info *i;

   ogg_int64_t granulepos;

   void *internal_encode;

   void *internal_decode;

 } theora_state;

 /** 

  * Comment header metadata.

  *

  * This structure holds the in-stream metadata corresponding to

  * the 'comment' header packet.

  *

  * Meta data is stored as a series of (tag, value) pairs, in

  * length-encoded string vectors. The first occurence of the 

  * '=' character delimits the tag and value. A particular tag

  * may occur more than once. The character set encoding for

  * the strings is always UTF-8, but the tag names are limited

  * to case-insensitive ASCII. See the spec for details.

  *

  * In filling in this structure, theora_decode_header() will

  * null-terminate the user_comment strings for safety. However,

  * the bitstream format itself treats them as 8-bit clean,

  * and so the length array should be treated as authoritative

  * for their length.

  */

 typedef struct theora_comment{

   char **user_comments;         /**< An array of comment string vectors */

   int   *comment_lengths;       /**< An array of corresponding string vector lengths in bytes */

   int    comments;              /**< The total number of comment string vectors */

   char  *vendor;                /**< The vendor string identifying the encoder, null terminated */

 } theora_comment;

 /**\name theora_control() codes */

 /* \anchor decctlcodes_old

  * These are the available request codes for theora_control()

  * when called with a decoder instance.

  * By convention decoder control codes are odd, to distinguish 

  * them from \ref encctlcodes_old "encoder control codes" which

  * are even.

  *

  * Note that since the 1.0 release, both the legacy and the final

  * implementation accept all the same control codes, but only the

  * final API declares the newer codes.

  *

  * Keep any experimental or vendor-specific values above \c 0x8000.*/

 /*@{*/

 /**Get the maximum post-processing level.

  * The decoder supports a post-processing filter that can improve

  * the appearance of the decoded images. This returns the highest

  * level setting for this post-processor, corresponding to maximum

  * improvement and computational expense.

  */

 #define TH_DECCTL_GET_PPLEVEL_MAX (1)

 /**Set the post-processing level.

  * Sets the level of post-processing to use when decoding the 

  * compressed stream. This must be a value between zero (off)

  * and the maximum returned by TH_DECCTL_GET_PPLEVEL_MAX.

  */

 #define TH_DECCTL_SET_PPLEVEL (3)

 /**Sets the maximum distance between key frames.

  * This can be changed during an encode, but will be bounded by

  *  <tt>1<<th_info#keyframe_granule_shift</tt>.

  * If it is set before encoding begins, th_info#keyframe_granule_shift will

  *  be enlarged appropriately.

  *

  * \param[in]  buf <tt>ogg_uint32_t</tt>: The maximum distance between key

  *                   frames.

  * \param[out] buf <tt>ogg_uint32_t</tt>: The actual maximum distance set.

  * \retval OC_FAULT  \a theora_state or \a buf is <tt>NULL</tt>.

  * \retval OC_EINVAL \a buf_sz is not <tt>sizeof(ogg_uint32_t)</tt>.

  * \retval OC_IMPL   Not supported by this implementation.*/

 #define TH_ENCCTL_SET_KEYFRAME_FREQUENCY_FORCE (4)

 /**Set the granule position.

  * Call this after a seek, to update the internal granulepos

  * in the decoder, to insure that subsequent frames are marked

  * properly. If you track timestamps yourself and do not use

  * the granule postion returned by the decoder, then you do

  * not need to use this control.

  */

 #define TH_DECCTL_SET_GRANPOS (5)

 /**\anchor encctlcodes_old */

 /**Sets the quantization parameters to use.

  * The parameters are copied, not stored by reference, so they can be freed

  *  after this call.

  * <tt>NULL</tt> may be specified to revert to the default parameters.

  *

  * \param[in] buf #th_quant_info

  * \retval OC_FAULT  \a theora_state is <tt>NULL</tt>.

  * \retval OC_EINVAL Encoding has already begun, the quantization parameters

  *                    are not acceptable to this version of the encoder, 

  *                    \a buf is <tt>NULL</tt> and \a buf_sz is not zero, 

  *                    or \a buf is non-<tt>NULL</tt> and \a buf_sz is 

  *                    not <tt>sizeof(#th_quant_info)</tt>.

  * \retval OC_IMPL   Not supported by this implementation.*/

 #define TH_ENCCTL_SET_QUANT_PARAMS (2)

 /**Disables any encoder features that would prevent lossless transcoding back

  *  to VP3.

  * This primarily means disabling block-level QI values and not using 4MV mode

  *  when any of the luma blocks in a macro block are not coded.

  * It also includes using the VP3 quantization tables and Huffman codes; if you

  *  set them explicitly after calling this function, the resulting stream will

  *  not be VP3-compatible.

  * If you enable VP3-compatibility when encoding 4:2:2 or 4:4:4 source

  *  material, or when using a picture region smaller than the full frame (e.g.

  *  a non-multiple-of-16 width or height), then non-VP3 bitstream features will

  *  still be disabled, but the stream will still not be VP3-compatible, as VP3

  *  was not capable of encoding such formats.

  * If you call this after encoding has already begun, then the quantization

  *  tables and codebooks cannot be changed, but the frame-level features will

  *  be enabled or disabled as requested.

  *

  * \param[in]  buf <tt>int</tt>: a non-zero value to enable VP3 compatibility,

  *                   or 0 to disable it (the default).

  * \param[out] buf <tt>int</tt>: 1 if all bitstream features required for

  *                   VP3-compatibility could be set, and 0 otherwise.

  *                  The latter will be returned if the pixel format is not

  *                   4:2:0, the picture region is smaller than the full frame,

  *                   or if encoding has begun, preventing the quantization

  *                   tables and codebooks from being set.

  * \retval OC_FAULT  \a theora_state or \a buf is <tt>NULL</tt>.

  * \retval OC_EINVAL \a buf_sz is not <tt>sizeof(int)</tt>.

  * \retval OC_IMPL   Not supported by this implementation.*/

 #define TH_ENCCTL_SET_VP3_COMPATIBLE (10)

 /**Gets the maximum speed level.

  * Higher speed levels favor quicker encoding over better quality per bit.

  * Depending on the encoding mode, and the internal algorithms used, quality

  *  may actually improve, but in this case bitrate will also likely increase.

  * In any case, overall rate/distortion performance will probably decrease.

  * The maximum value, and the meaning of each value, may change depending on

  *  the current encoding mode (VBR vs. CQI, etc.).

  *

  * \param[out] buf int: The maximum encoding speed level.

  * \retval OC_FAULT  \a theora_state or \a buf is <tt>NULL</tt>.

  * \retval OC_EINVAL \a buf_sz is not <tt>sizeof(int)</tt>.

  * \retval OC_IMPL   Not supported by this implementation in the current

  *                    encoding mode.*/

 #define TH_ENCCTL_GET_SPLEVEL_MAX (12)

 /**Sets the speed level.

  * By default a speed value of 1 is used.

  *

  * \param[in] buf int: The new encoding speed level.

  *                      0 is slowest, larger values use less CPU.

  * \retval OC_FAULT  \a theora_state or \a buf is <tt>NULL</tt>.

  * \retval OC_EINVAL \a buf_sz is not <tt>sizeof(int)</tt>, or the

  *                    encoding speed level is out of bounds.

  *                   The maximum encoding speed level may be

  *                    implementation- and encoding mode-specific, and can be

  *                    obtained via #TH_ENCCTL_GET_SPLEVEL_MAX.

  * \retval OC_IMPL   Not supported by this implementation in the current

  *                    encoding mode.*/

 #define TH_ENCCTL_SET_SPLEVEL (14)

 /*@}*/

 #define OC_FAULT       -1       /**< General failure */

 #define OC_EINVAL      -10      /**< Library encountered invalid internal data */

 #define OC_DISABLED    -11      /**< Requested action is disabled */

 #define OC_BADHEADER   -20      /**< Header packet was corrupt/invalid */

 #define OC_NOTFORMAT   -21      /**< Packet is not a theora packet */

 #define OC_VERSION     -22      /**< Bitstream version is not handled */

 #define OC_IMPL        -23      /**< Feature or action not implemented */

 #define OC_BADPACKET   -24      /**< Packet is corrupt */

 #define OC_NEWPACKET   -25      /**< Packet is an (ignorable) unhandled extension */

 #define OC_DUPFRAME    1        /**< Packet is a dropped frame */

 /** 

  * Retrieve a human-readable string to identify the encoder vendor and version.

  * \returns A version string.

  */

 extern const char *theora_version_string(void);

 /**

  * Retrieve a 32-bit version number.

  * This number is composed of a 16-bit major version, 8-bit minor version

  * and 8 bit sub-version, composed as follows:

 <pre>

    (VERSION_MAJOR<<16) + (VERSION_MINOR<<8) + (VERSION_SUB)

 </pre>

 * \returns The version number.

 */

 extern ogg_uint32_t theora_version_number(void);

 /**

  * Initialize the theora encoder.

  * \param th The theora_state handle to initialize for encoding.

  * \param ti A theora_info struct filled with the desired encoding parameters.

  * \retval 0 Success

  */

 extern int theora_encode_init(theora_state *th, theora_info *ti);

 /**

  * Submit a YUV buffer to the theora encoder.

  * \param t A theora_state handle previously initialized for encoding.

  * \param yuv A buffer of YUV data to encode.  Note that both the yuv_buffer

  *            struct and the luma/chroma buffers within should be allocated by

  *            the user.

  * \retval OC_EINVAL Encoder is not ready, or is finished.

  * \retval -1 The size of the given frame differs from those previously input

  * \retval 0 Success

  */

 extern int theora_encode_YUVin(theora_state *t, yuv_buffer *yuv);

 /**

  * Request the next packet of encoded video. 

  * The encoded data is placed in a user-provided ogg_packet structure.

  * \param t A theora_state handle previously initialized for encoding.

  * \param last_p whether this is the last packet the encoder should produce.

  * \param op An ogg_packet structure to fill. libtheora will set all

  *           elements of this structure, including a pointer to encoded

  *           data. The memory for the encoded data is owned by libtheora.

  * \retval 0 No internal storage exists OR no packet is ready

  * \retval -1 The encoding process has completed

  * \retval 1 Success

  */

 extern int theora_encode_packetout( theora_state *t, int last_p,

                                     ogg_packet *op);

 /**

  * Request a packet containing the initial header.

  * A pointer to the header data is placed in a user-provided ogg_packet

  * structure.

  * \param t A theora_state handle previously initialized for encoding.

  * \param op An ogg_packet structure to fill. libtheora will set all

  *           elements of this structure, including a pointer to the header

  *           data. The memory for the header data is owned by libtheora.

  * \retval 0 Success

  */

 extern int theora_encode_header(theora_state *t, ogg_packet *op);

 /**

  * Request a comment header packet from provided metadata.

  * A pointer to the comment data is placed in a user-provided ogg_packet

  * structure.

  * \param tc A theora_comment structure filled with the desired metadata

  * \param op An ogg_packet structure to fill. libtheora will set all

  *           elements of this structure, including a pointer to the encoded

  *           comment data. The memory for the comment data is owned by

  *           libtheora.

  * \retval 0 Success

  */

 extern int theora_encode_comment(theora_comment *tc, ogg_packet *op);

 /**

  * Request a packet containing the codebook tables for the stream.

  * A pointer to the codebook data is placed in a user-provided ogg_packet

  * structure.

  * \param t A theora_state handle previously initialized for encoding.

  * \param op An ogg_packet structure to fill. libtheora will set all

  *           elements of this structure, including a pointer to the codebook

  *           data. The memory for the header data is owned by libtheora.

  * \retval 0 Success

  */

 extern int theora_encode_tables(theora_state *t, ogg_packet *op);

 /**

  * Decode an Ogg packet, with the expectation that the packet contains

  * an initial header, comment data or codebook tables.

  *

  * \param ci A theora_info structure to fill. This must have been previously

  *           initialized with theora_info_init(). If \a op contains an initial

  *           header, theora_decode_header() will fill \a ci with the

  *           parsed header values. If \a op contains codebook tables,

  *           theora_decode_header() will parse these and attach an internal

  *           representation to \a ci->codec_setup.

  * \param cc A theora_comment structure to fill. If \a op contains comment

  *           data, theora_decode_header() will fill \a cc with the parsed

  *           comments.

  * \param op An ogg_packet structure which you expect contains an initial

  *           header, comment data or codebook tables.

  *

  * \retval OC_BADHEADER \a op is NULL; OR the first byte of \a op->packet

  *                      has the signature of an initial packet, but op is

  *                      not a b_o_s packet; OR this packet has the signature

  *                      of an initial header packet, but an initial header

  *                      packet has already been seen; OR this packet has the

  *                      signature of a comment packet, but the initial header

  *                      has not yet been seen; OR this packet has the signature

  *                      of a comment packet, but contains invalid data; OR

  *                      this packet has the signature of codebook tables,

  *                      but the initial header or comments have not yet

  *                      been seen; OR this packet has the signature of codebook

  *                      tables, but contains invalid data;

  *                      OR the stream being decoded has a compatible version

  *                      but this packet does not have the signature of a

  *                      theora initial header, comments, or codebook packet

  * \retval OC_VERSION   The packet data of \a op is an initial header with

  *                      a version which is incompatible with this version of

  *                      libtheora.

  * \retval OC_NEWPACKET the stream being decoded has an incompatible (future)

  *                      version and contains an unknown signature.

  * \retval 0            Success

  *

  * \note The normal usage is that theora_decode_header() be called on the

  *       first three packets of a theora logical bitstream in succession.

  */

 extern int theora_decode_header(theora_info *ci, theora_comment *cc,

                                 ogg_packet *op);

 /**

  * Initialize a theora_state handle for decoding.

  * \param th The theora_state handle to initialize.

  * \param c  A theora_info struct filled with the desired decoding parameters.

  *           This is of course usually obtained from a previous call to

  *           theora_decode_header().

  * \retval 0 Success

  */

 extern int theora_decode_init(theora_state *th, theora_info *c);

 /**

  * Input a packet containing encoded data into the theora decoder.

  * \param th A theora_state handle previously initialized for decoding.

  * \param op An ogg_packet containing encoded theora data.

  * \retval 0 Success

  * \retval OC_BADPACKET \a op does not contain encoded video data

  */

 extern int theora_decode_packetin(theora_state *th,ogg_packet *op);

 /**

  * Output the next available frame of decoded YUV data.

  * \param th A theora_state handle previously initialized for decoding.

  * \param yuv A yuv_buffer in which libtheora should place the decoded data.

  *            Note that the buffer struct itself is allocated by the user, but

  *            that the luma and chroma pointers will be filled in by the 

  *            library.  Also note that these luma and chroma regions should be 

  *            considered read-only by the user.

  * \retval 0 Success

  */

 extern int theora_decode_YUVout(theora_state *th,yuv_buffer *yuv);

 /**

  * Report whether a theora packet is a header or not

  * This function does no verification beyond checking the header

  * flag bit so it should not be used for bitstream identification;

  * use theora_decode_header() for that.

  *

  * \param op An ogg_packet containing encoded theora data.

  * \retval 1 The packet is a header packet

  * \retval 0 The packet is not a header packet (and so contains frame data)

  *

  * Thus function was added in the 1.0alpha4 release.

  */

 extern int theora_packet_isheader(ogg_packet *op);

 /**

  * Report whether a theora packet is a keyframe or not

  *

  * \param op An ogg_packet containing encoded theora data.

  * \retval 1 The packet contains a keyframe image

  * \retval 0 The packet is contains an interframe delta

  * \retval -1 The packet is not an image data packet at all

  *

  * Thus function was added in the 1.0alpha4 release.

  */

 extern int theora_packet_iskeyframe(ogg_packet *op);

 /**

  * Report the granulepos shift radix

  *

  * When embedded in Ogg, Theora uses a two-part granulepos, 

  * splitting the 64-bit field into two pieces. The more-significant

  * section represents the frame count at the last keyframe,

  * and the less-significant section represents the count of

  * frames since the last keyframe. In this way the overall

  * field is still non-decreasing with time, but usefully encodes

  * a pointer to the last keyframe, which is necessary for

  * correctly restarting decode after a seek. 

  *

  * This function reports the number of bits used to represent

  * the distance to the last keyframe, and thus how the granulepos

  * field must be shifted or masked to obtain the two parts.

  * 

  * Since libtheora returns compressed data in an ogg_packet

  * structure, this may be generally useful even if the Theora

  * packets are not being used in an Ogg container. 

  *

  * \param ti A previously initialized theora_info struct

  * \returns The bit shift dividing the two granulepos fields

  *

  * This function was added in the 1.0alpha5 release.

  */

 int theora_granule_shift(theora_info *ti);

 /**

  * Convert a granulepos to an absolute frame index, starting at 0.

  * The granulepos is interpreted in the context of a given theora_state handle.

  * 

  * Note that while the granulepos encodes the frame count (i.e. starting

  * from 1) this call returns the frame index, starting from zero. Thus

  * One can calculate the presentation time by multiplying the index by

  * the rate.

  *

  * \param th A previously initialized theora_state handle (encode or decode)

  * \param granulepos The granulepos to convert.

  * \returns The frame index corresponding to \a granulepos.

  * \retval -1 The given granulepos is undefined (i.e. negative)

  *

  * Thus function was added in the 1.0alpha4 release.

  */

 extern ogg_int64_t theora_granule_frame(theora_state *th,ogg_int64_t granulepos);

 /**

  * Convert a granulepos to absolute time in seconds. The granulepos is

  * interpreted in the context of a given theora_state handle, and gives

  * the end time of a frame's presentation as used in Ogg mux ordering.

  *

  * \param th A previously initialized theora_state handle (encode or decode)

  * \param granulepos The granulepos to convert.

  * \returns The absolute time in seconds corresponding to \a granulepos.

  *          This is the "end time" for the frame, or the latest time it should

  *           be displayed.

  *          It is not the presentation time.

  * \retval -1. The given granulepos is undefined (i.e. negative), or

  * \retval -1. The function has been disabled because floating 

  *              point support is not available.

  */

 extern double theora_granule_time(theora_state *th,ogg_int64_t granulepos);

 /**

  * Initialize a theora_info structure. All values within the given theora_info

  * structure are initialized, and space is allocated within libtheora for

  * internal codec setup data.

  * \param c A theora_info struct to initialize.

  */

 extern void theora_info_init(theora_info *c);

 /**

  * Clear a theora_info structure. All values within the given theora_info

  * structure are cleared, and associated internal codec setup data is freed.

  * \param c A theora_info struct to initialize.

  */

 extern void theora_info_clear(theora_info *c);

 /**

  * Free all internal data associated with a theora_state handle.

  * \param t A theora_state handle.

  */

 extern void theora_clear(theora_state *t);

 /**

  * Initialize an allocated theora_comment structure

  * \param tc An allocated theora_comment structure 

  **/

 extern void theora_comment_init(theora_comment *tc);

 /**

  * Add a comment to an initialized theora_comment structure

  * \param tc A previously initialized theora comment structure

  * \param comment A null-terminated string encoding the comment in the form

  *                "TAG=the value"

  *

  * Neither theora_comment_add() nor theora_comment_add_tag() support

  * comments containing null values, although the bitstream format

  * supports this. To add such comments you will need to manipulate

  * the theora_comment structure directly.

  **/

 extern void theora_comment_add(theora_comment *tc, char *comment);

 /**

  * Add a comment to an initialized theora_comment structure.

  * \param tc A previously initialized theora comment structure

  * \param tag A null-terminated string containing the tag 

  *            associated with the comment.

  * \param value The corresponding value as a null-terminated string

  *

  * Neither theora_comment_add() nor theora_comment_add_tag() support

  * comments containing null values, although the bitstream format

  * supports this. To add such comments you will need to manipulate

  * the theora_comment structure directly.

  **/

 extern void theora_comment_add_tag(theora_comment *tc,

                                        char *tag, char *value);

 /**

  * Look up a comment value by tag.

  * \param tc Tn initialized theora_comment structure

  * \param tag The tag to look up

  * \param count The instance of the tag. The same tag can appear multiple

  *              times, each with a distinct and ordered value, so an index

  *              is required to retrieve them all.

  * \returns A pointer to the queried tag's value

  * \retval NULL No matching tag is found

  *

  * \note Use theora_comment_query_count() to get the legal range for the

  * count parameter.

  **/

 extern char *theora_comment_query(theora_comment *tc, char *tag, int count);

 /** Look up the number of instances of a tag.

  *  \param tc An initialized theora_comment structure

  *  \param tag The tag to look up

  *  \returns The number on instances of a particular tag.

  * 

  *  Call this first when querying for a specific tag and then interate

  *  over the number of instances with separate calls to 

  *  theora_comment_query() to retrieve all instances in order.

  **/

 extern int   theora_comment_query_count(theora_comment *tc, char *tag);

 /**

  * Clear an allocated theora_comment struct so that it can be freed.

  * \param tc An allocated theora_comment structure.

  **/

 extern void  theora_comment_clear(theora_comment *tc);

 /**Encoder control function.

  * This is used to provide advanced control the encoding process.

  * \param th     A #theora_state handle.

  * \param req    The control code to process.

  *                See \ref encctlcodes_old "the list of available 

  *			control codes" for details.

  * \param buf    The parameters for this control code.

  * \param buf_sz The size of the parameter buffer.*/

 extern int theora_control(theora_state *th,int req,void *buf,size_t buf_sz);

 /* @} */ /* end oldfuncs doxygen group */

 #ifdef __cplusplus

 }

 #endif /* __cplusplus */

 #endif /* _O_THEORA_H_ */