diff options
Diffstat (limited to 'thirdparty/libtheora/theora/codec.h')
| -rw-r--r-- | thirdparty/libtheora/theora/codec.h | 591 |
1 files changed, 591 insertions, 0 deletions
diff --git a/thirdparty/libtheora/theora/codec.h b/thirdparty/libtheora/theora/codec.h new file mode 100644 index 0000000000..5c2669630c --- /dev/null +++ b/thirdparty/libtheora/theora/codec.h @@ -0,0 +1,591 @@ +/******************************************************************** + * * + * 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 1.8 2004/03/15 22:17:32 derf Exp $ + + ********************************************************************/ + +/**\mainpage + * + * \section intro Introduction + * + * This is the documentation for <tt>libtheora</tt> C API. + * The current reference + * implementation for <a href="http://www.theora.org/">Theora</a>, a free, + * patent-unencumbered video codec. + * Theora is derived from On2's VP3 codec with additional features and + * integration with Ogg multimedia formats by + * <a href="http://www.xiph.org/">the Xiph.Org Foundation</a>. + * Complete documentation of the format itself is available in + * <a href="http://www.theora.org/doc/Theora.pdf">the Theora + * specification</a>. + * + * \subsection Organization + * + * The functions documented here are actually subdivided into three + * separate libraries: + * - <tt>libtheoraenc</tt> contains the encoder interface, + * described in \ref encfuncs. + * - <tt>libtheoradec</tt> contains the decoder interface and + * routines shared with the encoder. + * You must also link to this if you link to <tt>libtheoraenc</tt>. + * The routines in this library are described in \ref decfuncs and + * \ref basefuncs. + * - <tt>libtheora</tt> contains the \ref oldfuncs. + * + * New code should link to <tt>libtheoradec</tt> and, if using encoder + * features, <tt>libtheoraenc</tt>. Together these two export both + * the standard and the legacy API, so this is all that is needed by + * any code. The older <tt>libtheora</tt> library is provided just for + * compatibility with older build configurations. + * + * In general the recommended 1.x API symbols can be distinguished + * by their <tt>th_</tt> or <tt>TH_</tt> namespace prefix. + * The older, legacy API uses <tt>theora_</tt> or <tt>OC_</tt> + * prefixes instead. + */ + +/**\file + * The shared <tt>libtheoradec</tt> and <tt>libtheoraenc</tt> C API. + * You don't need to include this directly.*/ + +#if !defined(_O_THEORA_CODEC_H_) +# define _O_THEORA_CODEC_H_ (1) +# include <ogg/ogg.h> + +#if defined(__cplusplus) +extern "C" { +#endif + + + +/**\name Return codes*/ +/*@{*/ +/**An invalid pointer was provided.*/ +#define TH_EFAULT (-1) +/**An invalid argument was provided.*/ +#define TH_EINVAL (-10) +/**The contents of the header were incomplete, invalid, or unexpected.*/ +#define TH_EBADHEADER (-20) +/**The header does not belong to a Theora stream.*/ +#define TH_ENOTFORMAT (-21) +/**The bitstream version is too high.*/ +#define TH_EVERSION (-22) +/**The specified function is not implemented.*/ +#define TH_EIMPL (-23) +/**There were errors in the video data packet.*/ +#define TH_EBADPACKET (-24) +/**The decoded packet represented a dropped frame. + The player can continue to display the current frame, as the contents of the + decoded frame buffer have not changed.*/ +#define TH_DUPFRAME (1) +/*@}*/ + +/**The currently defined color space tags. + * See <a href="http://www.theora.org/doc/Theora.pdf">the Theora + * specification</a>, Chapter 4, for exact details on the meaning + * of each of these color spaces.*/ +typedef enum{ + /**The color space was not specified at the encoder. + It may be conveyed by an external means.*/ + TH_CS_UNSPECIFIED, + /**A color space designed for NTSC content.*/ + TH_CS_ITU_REC_470M, + /**A color space designed for PAL/SECAM content.*/ + TH_CS_ITU_REC_470BG, + /**The total number of currently defined color spaces.*/ + TH_CS_NSPACES +}th_colorspace; + +/**The currently defined pixel format tags. + * See <a href="http://www.theora.org/doc/Theora.pdf">the Theora + * specification</a>, Section 4.4, for details on the precise sample + * locations.*/ +typedef enum{ + /**Chroma decimation by 2 in both the X and Y directions (4:2:0). + The Cb and Cr chroma planes are half the width and half the + height of the luma plane.*/ + TH_PF_420, + /**Currently reserved.*/ + TH_PF_RSVD, + /**Chroma decimation by 2 in the X direction (4:2:2). + The Cb and Cr chroma planes are half the width of the luma plane, but full + height.*/ + TH_PF_422, + /**No chroma decimation (4:4:4). + The Cb and Cr chroma planes are full width and full height.*/ + TH_PF_444, + /**The total number of currently defined pixel formats.*/ + TH_PF_NFORMATS +}th_pixel_fmt; + + + +/**A buffer for a single color plane in an uncompressed image. + * This contains the image data in a left-to-right, top-down format. + * Each row of pixels is stored contiguously in memory, but successive + * rows need not be. + * Use \a stride to compute the offset of the next row. + * The encoder accepts both positive \a stride values (top-down in memory) + * and negative (bottom-up in memory). + * The decoder currently always generates images with positive strides.*/ +typedef struct{ + /**The width of this plane.*/ + int width; + /**The height of this plane.*/ + int height; + /**The offset in bytes between successive rows.*/ + int stride; + /**A pointer to the beginning of the first row.*/ + unsigned char *data; +}th_img_plane; + +/**A complete image buffer for an uncompressed frame. + * The chroma planes may be decimated by a factor of two in either + * direction, as indicated by th_info#pixel_fmt. + * The width and height of the Y' plane must be multiples of 16. + * They may need to be cropped for display, using the rectangle + * specified by th_info#pic_x, th_info#pic_y, th_info#pic_width, + * and th_info#pic_height. + * All samples are 8 bits. + * \note The term YUV often used to describe a colorspace is ambiguous. + * The exact parameters of the RGB to YUV conversion process aside, in + * many contexts the U and V channels actually have opposite meanings. + * To avoid this confusion, we are explicit: the name of the color + * channels are Y'CbCr, and they appear in that order, always. + * The prime symbol denotes that the Y channel is non-linear. + * Cb and Cr stand for "Chroma blue" and "Chroma red", respectively.*/ +typedef th_img_plane th_ycbcr_buffer[3]; + +/**Theora bitstream information. + * This contains the basic playback parameters for a stream, and corresponds to + * the initial 'info' header packet. + * To initialize an encoder, the application fills in this structure and + * passes it to th_encode_alloc(). + * A default encoding mode is chosen based on the values of the #quality and + * #target_bitrate fields. + * On decode, it is filled in by th_decode_headerin(), and then passed to + * th_decode_alloc(). + * + * Encoded Theora frames must be a multiple of 16 in size; + * this is what the #frame_width and #frame_height members represent. + * To handle arbitrary picture sizes, a crop rectangle is specified in the + * #pic_x, #pic_y, #pic_width and #pic_height members. + * + * All frame buffers contain pointers to the full, padded frame. + * However, the current encoder <em>will not</em> reference pixels outside of + * the cropped picture region, and the application does not need to fill them + * in. + * The decoder <em>will</em> allocate storage for a full frame, but the + * application <em>should not</em> rely on the padding containing sensible + * data. + * + * It is also generally recommended that the offsets and sizes should still be + * multiples of 2 to avoid chroma sampling shifts when chroma is sub-sampled. + * See <a href="http://www.theora.org/doc/Theora.pdf">the Theora + * specification</a>, Section 4.4, for more details. + * + * Frame rate, in frames per second, is stored as a rational fraction, as is + * the pixel aspect ratio. + * Note that this refers to the aspect ratio of the individual pixels, not of + * the overall frame itself. + * The frame aspect ratio can be computed from pixel aspect ratio using the + * image dimensions.*/ +typedef struct{ + /**\name Theora version + * Bitstream version information.*/ + /*@{*/ + unsigned char version_major; + unsigned char version_minor; + unsigned char version_subminor; + /*@}*/ + /**The encoded frame width. + * This must be a multiple of 16, and less than 1048576.*/ + ogg_uint32_t frame_width; + /**The encoded frame height. + * This must be a multiple of 16, and less than 1048576.*/ + ogg_uint32_t frame_height; + /**The displayed picture width. + * This must be no larger than width.*/ + ogg_uint32_t pic_width; + /**The displayed picture height. + * This must be no larger than height.*/ + ogg_uint32_t pic_height; + /**The X offset of the displayed picture. + * This must be no larger than #frame_width-#pic_width or 255, whichever is + * smaller.*/ + ogg_uint32_t pic_x; + /**The Y offset of the displayed picture. + * This must be no larger than #frame_height-#pic_height, and + * #frame_height-#pic_height-#pic_y must be no larger than 255. + * This slightly funny restriction is due to the fact that the offset is + * specified from the top of the image for consistency with the standard + * graphics left-handed coordinate system used throughout this API, while + * it is stored in the encoded stream as an offset from the bottom.*/ + ogg_uint32_t pic_y; + /**\name Frame rate + * The frame rate, as a fraction. + * If either is 0, the frame rate is undefined.*/ + /*@{*/ + ogg_uint32_t fps_numerator; + ogg_uint32_t fps_denominator; + /*@}*/ + /**\name Aspect ratio + * The aspect ratio of the pixels. + * If either value is zero, the aspect ratio is undefined. + * If not specified by any external means, 1:1 should be assumed. + * The aspect ratio of the full picture can be computed as + * \code + * aspect_numerator*pic_width/(aspect_denominator*pic_height). + * \endcode */ + /*@{*/ + ogg_uint32_t aspect_numerator; + ogg_uint32_t aspect_denominator; + /*@}*/ + /**The color space.*/ + th_colorspace colorspace; + /**The pixel format.*/ + th_pixel_fmt pixel_fmt; + /**The target bit-rate in bits per second. + If initializing an encoder with this struct, set this field to a non-zero + value to activate CBR encoding by default.*/ + int target_bitrate; + /**The target quality level. + Valid values range from 0 to 63, inclusive, with higher values giving + higher quality. + If initializing an encoder with this struct, and #target_bitrate is set + to zero, VBR encoding at this quality will be activated by default.*/ + /*Currently this is set so that a qi of 0 corresponds to distortions of 24 + times the JND, and each increase by 16 halves that value. + This gives us fine discrimination at low qualities, yet effective rate + control at high qualities. + The qi value 63 is special, however. + For this, the highest quality, we use one half of a JND for our threshold. + Due to the lower bounds placed on allowable quantizers in Theora, we will + not actually be able to achieve quality this good, but this should + provide as close to visually lossless quality as Theora is capable of. + We could lift the quantizer restrictions without breaking VP3.1 + compatibility, but this would result in quantized coefficients that are + too large for the current bitstream to be able to store. + We'd have to redesign the token syntax to store these large coefficients, + which would make transcoding complex.*/ + int quality; + /**The amount to shift to extract the last keyframe number from the granule + * position. + * This can be at most 31. + * th_info_init() will set this to a default value (currently <tt>6</tt>, + * which is good for streaming applications), but you can set it to 0 to + * make every frame a keyframe. + * The maximum distance between key frames is + * <tt>1<<#keyframe_granule_shift</tt>. + * The keyframe frequency can be more finely controlled with + * #TH_ENCCTL_SET_KEYFRAME_FREQUENCY_FORCE, which can also be adjusted + * during encoding (for example, to force the next frame to be a keyframe), + * but it cannot be set larger than the amount permitted by this field after + * the headers have been output.*/ + int keyframe_granule_shift; +}th_info; + +/**The comment information. + * + * This structure holds the in-stream metadata corresponding to + * the 'comment' header packet. + * The comment header is meant to be used much like someone jotting a quick + * note on the label of a video. + * It should be a short, to the point text note that can be more than a couple + * words, but not more than a short paragraph. + * + * The metadata is stored as a series of (tag, value) pairs, in + * length-encoded string vectors. + * The first occurrence of the '=' character delimits the tag and value. + * A particular tag may occur more than once, and order is significant. + * The character set encoding for the strings is always UTF-8, but the tag + * names are limited to ASCII, and treated as case-insensitive. + * See <a href="http://www.theora.org/doc/Theora.pdf">the Theora + * specification</a>, Section 6.3.3 for details. + * + * In filling in this structure, th_decode_headerin() will null-terminate + * the user_comment strings for safety. + * However, the bitstream format itself treats them as 8-bit clean vectors, + * possibly containing null characters, and so the length array should be + * treated as their authoritative length. + */ +typedef struct th_comment{ + /**The array of comment string vectors.*/ + char **user_comments; + /**An array of the corresponding length of each vector, in bytes.*/ + int *comment_lengths; + /**The total number of comment strings.*/ + int comments; + /**The null-terminated vendor string. + This identifies the software used to encode the stream.*/ + char *vendor; +}th_comment; + + + +/**A single base matrix.*/ +typedef unsigned char th_quant_base[64]; + +/**A set of \a qi ranges.*/ +typedef struct{ + /**The number of ranges in the set.*/ + int nranges; + /**The size of each of the #nranges ranges. + These must sum to 63.*/ + const int *sizes; + /**#nranges <tt>+1</tt> base matrices. + Matrices \a i and <tt>i+1</tt> form the endpoints of range \a i.*/ + const th_quant_base *base_matrices; +}th_quant_ranges; + +/**A complete set of quantization parameters. + The quantizer for each coefficient is calculated as: + \code + Q=MAX(MIN(qmin[qti][ci!=0],scale[ci!=0][qi]*base[qti][pli][qi][ci]/100), + 1024). + \endcode + + \a qti is the quantization type index: 0 for intra, 1 for inter. + <tt>ci!=0</tt> is 0 for the DC coefficient and 1 for AC coefficients. + \a qi is the quality index, ranging between 0 (low quality) and 63 (high + quality). + \a pli is the color plane index: 0 for Y', 1 for Cb, 2 for Cr. + \a ci is the DCT coefficient index. + Coefficient indices correspond to the normal 2D DCT block + ordering--row-major with low frequencies first--\em not zig-zag order. + + Minimum quantizers are constant, and are given by: + \code + qmin[2][2]={{4,2},{8,4}}. + \endcode + + Parameters that can be stored in the bitstream are as follows: + - The two scale matrices ac_scale and dc_scale. + \code + scale[2][64]={dc_scale,ac_scale}. + \endcode + - The base matrices for each \a qi, \a qti and \a pli (up to 384 in all). + In order to avoid storing a full 384 base matrices, only a sparse set of + matrices are stored, and the rest are linearly interpolated. + This is done as follows. + For each \a qti and \a pli, a series of \a n \a qi ranges is defined. + The size of each \a qi range can vary arbitrarily, but they must sum to + 63. + Then, <tt>n+1</tt> matrices are specified, one for each endpoint of the + ranges. + For interpolation purposes, each range's endpoints are the first \a qi + value it contains and one past the last \a qi value it contains. + Fractional values are rounded to the nearest integer, with ties rounded + away from zero. + + Base matrices are stored by reference, so if the same matrices are used + multiple times, they will only appear once in the bitstream. + The bitstream is also capable of omitting an entire set of ranges and + its associated matrices if they are the same as either the previous + set (indexed in row-major order) or if the inter set is the same as the + intra set. + + - Loop filter limit values. + The same limits are used for the loop filter in all color planes, despite + potentially differing levels of quantization in each. + + 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. + This is not required by the decoder.*/ +typedef struct{ + /**The DC scaling factors.*/ + ogg_uint16_t dc_scale[64]; + /**The AC scaling factors.*/ + ogg_uint16_t ac_scale[64]; + /**The loop filter limit values.*/ + unsigned char loop_filter_limits[64]; + /**The \a qi ranges for each \a ci and \a pli.*/ + th_quant_ranges qi_ranges[2][3]; +}th_quant_info; + + + +/**The number of Huffman tables used by Theora.*/ +#define TH_NHUFFMAN_TABLES (80) +/**The number of DCT token values in each table.*/ +#define TH_NDCT_TOKENS (32) + +/**A Huffman code for a Theora DCT token. + * Each set of Huffman codes in a given table must form a complete, prefix-free + * code. + * There is no requirement that all the tokens in a table have a valid code, + * but the current encoder is not optimized to take advantage of this. + * If each of the five grouops of 16 tables does not contain at least one table + * with a code for every token, then the encoder may fail to encode certain + * frames. + * The complete table in the first group of 16 does not have to be in the same + * place as the complete table in the other groups, but the complete tables in + * the remaining four groups must all be in the same place.*/ +typedef struct{ + /**The bit pattern for the code, with the LSbit of the pattern aligned in + * the LSbit of the word.*/ + ogg_uint32_t pattern; + /**The number of bits in the code. + * This must be between 0 and 32, inclusive.*/ + int nbits; +}th_huff_code; + + + +/**\defgroup basefuncs Functions Shared by Encode and Decode*/ +/*@{*/ +/**\name Basic shared functions*/ +/*@{*/ +/**Retrieves a human-readable string to identify the library vendor and + * version. + * \return the version string.*/ +extern const char *th_version_string(void); +/**Retrieves the library version number. + * This is the highest bitstream version that the encoder library will produce, + * or that the decoder library can decode. + * This number is composed of a 16-bit major version, 8-bit minor version + * and 8 bit sub-version, composed as follows: + * \code + * (VERSION_MAJOR<<16)+(VERSION_MINOR<<8)+(VERSION_SUBMINOR) + * \endcode + * \return the version number.*/ +extern ogg_uint32_t th_version_number(void); +/**Converts a granule position to an absolute frame index, starting at + * <tt>0</tt>. + * The granule position is interpreted in the context of a given + * #th_enc_ctx or #th_dec_ctx handle (either will suffice). + * \param _encdec A previously allocated #th_enc_ctx or #th_dec_ctx + * handle. + * \param _granpos The granule position to convert. + * \returns The absolute frame index corresponding to \a _granpos. + * \retval -1 The given granule position was invalid (i.e. negative).*/ +extern ogg_int64_t th_granule_frame(void *_encdec,ogg_int64_t _granpos); +/**Converts a granule position to an absolute time in seconds. + * The granule position is interpreted in the context of a given + * #th_enc_ctx or #th_dec_ctx handle (either will suffice). + * \param _encdec A previously allocated #th_enc_ctx or #th_dec_ctx + * handle. + * \param _granpos The granule position to convert. + * \return The absolute time in seconds corresponding to \a _granpos. + * 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 granule position was invalid (i.e. negative).*/ +extern double th_granule_time(void *_encdec,ogg_int64_t _granpos); +/**Determines whether a Theora packet is a header or not. + * This function does no verification beyond checking the packet type bit, so + * it should not be used for bitstream identification; use + * th_decode_headerin() for that. + * As per the Theora specification, an empty (0-byte) packet is treated as a + * data packet (a delta frame with no coded blocks). + * \param _op An <tt>ogg_packet</tt> containing encoded Theora data. + * \retval 1 The packet is a header packet + * \retval 0 The packet is a video data packet.*/ +extern int th_packet_isheader(ogg_packet *_op); +/**Determines whether a theora packet is a key frame or not. + * This function does no verification beyond checking the packet type and + * key frame bits, so it should not be used for bitstream identification; use + * th_decode_headerin() for that. + * As per the Theora specification, an empty (0-byte) packet is treated as a + * delta frame (with no coded blocks). + * \param _op An <tt>ogg_packet</tt> containing encoded Theora data. + * \retval 1 The packet contains a key frame. + * \retval 0 The packet contains a delta frame. + * \retval -1 The packet is not a video data packet.*/ +extern int th_packet_iskeyframe(ogg_packet *_op); +/*@}*/ + + +/**\name Functions for manipulating header data*/ +/*@{*/ +/**Initializes a th_info structure. + * This should be called on a freshly allocated #th_info structure before + * attempting to use it. + * \param _info The #th_info struct to initialize.*/ +extern void th_info_init(th_info *_info); +/**Clears a #th_info structure. + * This should be called on a #th_info structure after it is no longer + * needed. + * \param _info The #th_info struct to clear.*/ +extern void th_info_clear(th_info *_info); + +/**Initialize a #th_comment structure. + * This should be called on a freshly allocated #th_comment structure + * before attempting to use it. + * \param _tc The #th_comment struct to initialize.*/ +extern void th_comment_init(th_comment *_tc); +/**Add a comment to an initialized #th_comment structure. + * \note Neither th_comment_add() nor th_comment_add_tag() support + * comments containing null values, although the bitstream format does + * support them. + * To add such comments you will need to manipulate the #th_comment + * structure directly. + * \param _tc The #th_comment struct to add the comment to. + * \param _comment Must be a null-terminated UTF-8 string containing the + * comment in "TAG=the value" form.*/ +extern void th_comment_add(th_comment *_tc, char *_comment); +/**Add a comment to an initialized #th_comment structure. + * \note Neither th_comment_add() nor th_comment_add_tag() support + * comments containing null values, although the bitstream format does + * support them. + * To add such comments you will need to manipulate the #th_comment + * structure directly. + * \param _tc The #th_comment struct to add the comment to. + * \param _tag A null-terminated string containing the tag associated with + * the comment. + * \param _val The corresponding value as a null-terminated string.*/ +extern void th_comment_add_tag(th_comment *_tc,char *_tag,char *_val); +/**Look up a comment value by its tag. + * \param _tc An initialized #th_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 + * value, so an index is required to retrieve them all. + * The order in which these values appear is significant and + * should be preserved. + * Use th_comment_query_count() to get the legal range for + * the \a _count parameter. + * \return A pointer to the queried tag's value. + * This points directly to data in the #th_comment structure. + * It should not be modified or freed by the application, and + * modifications to the structure may invalidate the pointer. + * \retval NULL If no matching tag is found.*/ +extern char *th_comment_query(th_comment *_tc,char *_tag,int _count); +/**Look up the number of instances of a tag. + * Call this first when querying for a specific tag and then iterate over the + * number of instances with separate calls to th_comment_query() to + * retrieve all the values for that tag in order. + * \param _tc An initialized #th_comment structure. + * \param _tag The tag to look up. + * \return The number on instances of this particular tag.*/ +extern int th_comment_query_count(th_comment *_tc,char *_tag); +/**Clears a #th_comment structure. + * This should be called on a #th_comment structure after it is no longer + * needed. + * It will free all memory used by the structure members. + * \param _tc The #th_comment struct to clear.*/ +extern void th_comment_clear(th_comment *_tc); +/*@}*/ +/*@}*/ + + + +#if defined(__cplusplus) +} +#endif + +#endif |