/********************************************************************
* *
* 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) 2002-2007 *
* by the Xiph.Org Foundation http://www.xiph.org/ *
* *
********************************************************************
function:
last mod: $Id: theora.h,v 1.2 2008-12-02 18:04:43 jeanlf 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>
/** \defgroup oldfuncs Legacy pre-1.0 C API */
/* @{ */
/** \mainpage
*
* \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 for
* 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.
*
* \subsection example Example Decoder
*
* See <a href="http://svn.xiph.org/trunk/theora/examples/dump_video.c">
* examples/dump_video.c</a> for a simple decoder implementation.
*
* \section encoding Encoding Process
*
* See <a href="http://svn.xiph.org/trunk/theora/examples/encoder_example.c">
* examples/encoder_example.c</a> for a simple encoder implementation.
*/
/** \file
* The libtheora pre-1.0 legacy 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
* These are the available request codes for theora_control()
* when called with a decoder instance.
* By convention, these are odd, to distinguish them from the
* \ref encctlcodes "encoder control 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 TH_FAULT \a theora_state or \a buf is <tt>NULL</tt>.
* \retval TH_EINVAL \a buf_sz is not <tt>sizeof(ogg_uint32_t)</tt>.
* \retval TH_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
* These are the available request codes for theora_control()
* when called with an encoder instance.
* By convention, these are even, to distinguish them from the
* \ref decctlcodes "decoder control codes".
* Keep any experimental or vendor-specific values above \c 0x8000.*/
/*@{*/
/**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.
* For the current encoder, <tt>scale[ci!=0][qi]</tt> must be no greater than
* <tt>scale[ci!=0][qi-1]</tt> and <tt>base[qti][pli][qi][ci]</tt> must be no
* greater than <tt>base[qti][pli][qi-1][ci]</tt>.
* These two conditions ensure that the actual quantizer for a given \a qti,
* \a pli, and \a ci does not increase as \a qi increases.
*
* \param[in] buf #th_quant_info
* \retval TH_FAULT \a theora_state is <tt>NULL</tt>.
* \retval TH_EINVAL Encoding has already begun, the quantization parameters
* do not meet one of the above stated conditions, \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 TH_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 TH_FAULT \a theora_state or \a buf is <tt>NULL</tt>.
* \retval TH_EINVAL \a buf_sz is not <tt>sizeof(int)</tt>.
* \retval TH_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 TH_FAULT \a theora_state or \a buf is <tt>NULL</tt>.
* \retval TH_EINVAL \a buf_sz is not <tt>sizeof(int)</tt>.
* \retval TH_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 TH_FAULT \a theora_state or \a buf is <tt>NULL</tt>.
* \retval TH_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 TH_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 "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_ */