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편집 파일: demux.h

// Copyright 2012 Google Inc. All Rights Reserved. // // Use of this source code is governed by a BSD-style license // that can be found in the COPYING file in the root of the source // tree. An additional intellectual property rights grant can be found // in the file PATENTS. All contributing project authors may // be found in the AUTHORS file in the root of the source tree. // ----------------------------------------------------------------------------- // // Demux API. // Enables extraction of image and extended format data from WebP files. // Code Example: Demuxing WebP data to extract all the frames, ICC profile // and EXIF/XMP metadata. /* WebPDemuxer* demux = WebPDemux(&webp_data); uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH); uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT); // ... (Get information about the features present in the WebP file). uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS); // ... (Iterate over all frames). WebPIterator iter; if (WebPDemuxGetFrame(demux, 1, &iter)) { do { // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(), // ... and get other frame properties like width, height, offsets etc. // ... see 'struct WebPIterator' below for more info). } while (WebPDemuxNextFrame(&iter)); WebPDemuxReleaseIterator(&iter); } // ... (Extract metadata). WebPChunkIterator chunk_iter; if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter); // ... (Consume the ICC profile in 'chunk_iter.chunk'). WebPDemuxReleaseChunkIterator(&chunk_iter); if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter); // ... (Consume the EXIF metadata in 'chunk_iter.chunk'). WebPDemuxReleaseChunkIterator(&chunk_iter); if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter); // ... (Consume the XMP metadata in 'chunk_iter.chunk'). WebPDemuxReleaseChunkIterator(&chunk_iter); WebPDemuxDelete(demux); */ #ifndef WEBP_WEBP_DEMUX_H_ #define WEBP_WEBP_DEMUX_H_ #include "./decode.h" // for WEBP_CSP_MODE #include "./mux_types.h" #ifdef __cplusplus extern "C" { #endif #define WEBP_DEMUX_ABI_VERSION 0x0107 // MAJOR(8b) + MINOR(8b) // Note: forward declaring enumerations is not allowed in (strict) C and C++, // the types are left here for reference. // typedef enum WebPDemuxState WebPDemuxState; // typedef enum WebPFormatFeature WebPFormatFeature; typedef struct WebPDemuxer WebPDemuxer; typedef struct WebPIterator WebPIterator; typedef struct WebPChunkIterator WebPChunkIterator; typedef struct WebPAnimInfo WebPAnimInfo; typedef struct WebPAnimDecoderOptions WebPAnimDecoderOptions; //------------------------------------------------------------------------------ // Returns the version number of the demux library, packed in hexadecimal using // 8bits for each of major/minor/revision. E.g: v2.5.7 is 0x020507. WEBP_EXTERN int WebPGetDemuxVersion(void); //------------------------------------------------------------------------------ // Life of a Demux object typedef enum WebPDemuxState { WEBP_DEMUX_PARSE_ERROR = -1, // An error occurred while parsing. WEBP_DEMUX_PARSING_HEADER = 0, // Not enough data to parse full header. WEBP_DEMUX_PARSED_HEADER = 1, // Header parsing complete, // data may be available. WEBP_DEMUX_DONE = 2 // Entire file has been parsed. } WebPDemuxState; // Internal, version-checked, entry point WEBP_EXTERN WebPDemuxer* WebPDemuxInternal( const WebPData*, int, WebPDemuxState*, int); // Parses the full WebP file given by 'data'. For single images the WebP file // header alone or the file header and the chunk header may be absent. // Returns a WebPDemuxer object on successful parse, NULL otherwise. static WEBP_INLINE WebPDemuxer* WebPDemux(const WebPData* data) { return WebPDemuxInternal(data, 0, NULL, WEBP_DEMUX_ABI_VERSION); } // Parses the possibly incomplete WebP file given by 'data'. // If 'state' is non-NULL it will be set to indicate the status of the demuxer. // Returns NULL in case of error or if there isn't enough data to start parsing; // and a WebPDemuxer object on successful parse. // Note that WebPDemuxer keeps internal pointers to 'data' memory segment. // If this data is volatile, the demuxer object should be deleted (by calling // WebPDemuxDelete()) and WebPDemuxPartial() called again on the new data. // This is usually an inexpensive operation. static WEBP_INLINE WebPDemuxer* WebPDemuxPartial( const WebPData* data, WebPDemuxState* state) { return WebPDemuxInternal(data, 1, state, WEBP_DEMUX_ABI_VERSION); } // Frees memory associated with 'dmux'. WEBP_EXTERN void WebPDemuxDelete(WebPDemuxer* dmux); //------------------------------------------------------------------------------ // Data/information extraction. typedef enum WebPFormatFeature { WEBP_FF_FORMAT_FLAGS, // bit-wise combination of WebPFeatureFlags // corresponding to the 'VP8X' chunk (if present). WEBP_FF_CANVAS_WIDTH, WEBP_FF_CANVAS_HEIGHT, WEBP_FF_LOOP_COUNT, // only relevant for animated file WEBP_FF_BACKGROUND_COLOR, // idem. WEBP_FF_FRAME_COUNT // Number of frames present in the demux object. // In case of a partial demux, this is the number // of frames seen so far, with the last frame // possibly being partial. } WebPFormatFeature; // Get the 'feature' value from the 'dmux'. // NOTE: values are only valid if WebPDemux() was used or WebPDemuxPartial() // returned a state > WEBP_DEMUX_PARSING_HEADER. // If 'feature' is WEBP_FF_FORMAT_FLAGS, the returned value is a bit-wise // combination of WebPFeatureFlags values. // If 'feature' is WEBP_FF_LOOP_COUNT, WEBP_FF_BACKGROUND_COLOR, the returned // value is only meaningful if the bitstream is animated. WEBP_EXTERN uint32_t WebPDemuxGetI( const WebPDemuxer* dmux, WebPFormatFeature feature); //------------------------------------------------------------------------------ // Frame iteration. struct WebPIterator { int frame_num; int num_frames; // equivalent to WEBP_FF_FRAME_COUNT. int x_offset, y_offset; // offset relative to the canvas. int width, height; // dimensions of this frame. int duration; // display duration in milliseconds. WebPMuxAnimDispose dispose_method; // dispose method for the frame. int complete; // true if 'fragment' contains a full frame. partial images // may still be decoded with the WebP incremental decoder. WebPData fragment; // The frame given by 'frame_num'. Note for historical // reasons this is called a fragment. int has_alpha; // True if the frame contains transparency. WebPMuxAnimBlend blend_method; // Blend operation for the frame. uint32_t pad[2]; // padding for later use. void* private_; // for internal use only. }; // Retrieves frame 'frame_number' from 'dmux'. // 'iter->fragment' points to the frame on return from this function. // Setting 'frame_number' equal to 0 will return the last frame of the image. // Returns false if 'dmux' is NULL or frame 'frame_number' is not present. // Call WebPDemuxReleaseIterator() when use of the iterator is complete. // NOTE: 'dmux' must persist for the lifetime of 'iter'. WEBP_EXTERN int WebPDemuxGetFrame( const WebPDemuxer* dmux, int frame_number, WebPIterator* iter); // Sets 'iter->fragment' to point to the next ('iter->frame_num' + 1) or // previous ('iter->frame_num' - 1) frame. These functions do not loop. // Returns true on success, false otherwise. WEBP_EXTERN int WebPDemuxNextFrame(WebPIterator* iter); WEBP_EXTERN int WebPDemuxPrevFrame(WebPIterator* iter); // Releases any memory associated with 'iter'. // Must be called before any subsequent calls to WebPDemuxGetChunk() on the same // iter. Also, must be called before destroying the associated WebPDemuxer with // WebPDemuxDelete(). WEBP_EXTERN void WebPDemuxReleaseIterator(WebPIterator* iter); //------------------------------------------------------------------------------ // Chunk iteration. struct WebPChunkIterator { // The current and total number of chunks with the fourcc given to // WebPDemuxGetChunk(). int chunk_num; int num_chunks; WebPData chunk; // The payload of the chunk. uint32_t pad[6]; // padding for later use void* private_; }; // Retrieves the 'chunk_number' instance of the chunk with id 'fourcc' from // 'dmux'. // 'fourcc' is a character array containing the fourcc of the chunk to return, // e.g., "ICCP", "XMP ", "EXIF", etc. // Setting 'chunk_number' equal to 0 will return the last chunk in a set. // Returns true if the chunk is found, false otherwise. Image related chunk // payloads are accessed through WebPDemuxGetFrame() and related functions. // Call WebPDemuxReleaseChunkIterator() when use of the iterator is complete. // NOTE: 'dmux' must persist for the lifetime of the iterator. WEBP_EXTERN int WebPDemuxGetChunk(const WebPDemuxer* dmux, const char fourcc[4], int chunk_number, WebPChunkIterator* iter); // Sets 'iter->chunk' to point to the next ('iter->chunk_num' + 1) or previous // ('iter->chunk_num' - 1) chunk. These functions do not loop. // Returns true on success, false otherwise. WEBP_EXTERN int WebPDemuxNextChunk(WebPChunkIterator* iter); WEBP_EXTERN int WebPDemuxPrevChunk(WebPChunkIterator* iter); // Releases any memory associated with 'iter'. // Must be called before destroying the associated WebPDemuxer with // WebPDemuxDelete(). WEBP_EXTERN void WebPDemuxReleaseChunkIterator(WebPChunkIterator* iter); //------------------------------------------------------------------------------ // WebPAnimDecoder API // // This API allows decoding (possibly) animated WebP images. // // Code Example: /* WebPAnimDecoderOptions dec_options; WebPAnimDecoderOptionsInit(&dec_options); // Tune 'dec_options' as needed. WebPAnimDecoder* dec = WebPAnimDecoderNew(webp_data, &dec_options); WebPAnimInfo anim_info; WebPAnimDecoderGetInfo(dec, &anim_info); for (uint32_t i = 0; i < anim_info.loop_count; ++i) { while (WebPAnimDecoderHasMoreFrames(dec)) { uint8_t* buf; int timestamp; WebPAnimDecoderGetNext(dec, &buf, &timestamp); // ... (Render 'buf' based on 'timestamp'). // ... (Do NOT free 'buf', as it is owned by 'dec'). } WebPAnimDecoderReset(dec); } const WebPDemuxer* demuxer = WebPAnimDecoderGetDemuxer(dec); // ... (Do something using 'demuxer'; e.g. get EXIF/XMP/ICC data). WebPAnimDecoderDelete(dec); */ typedef struct WebPAnimDecoder WebPAnimDecoder; // Main opaque object. // Global options. struct WebPAnimDecoderOptions { // Output colorspace. Only the following modes are supported: // MODE_RGBA, MODE_BGRA, MODE_rgbA and MODE_bgrA. WEBP_CSP_MODE color_mode; int use_threads; // If true, use multi-threaded decoding. uint32_t padding[7]; // Padding for later use. }; // Internal, version-checked, entry point. WEBP_EXTERN int WebPAnimDecoderOptionsInitInternal( WebPAnimDecoderOptions*, int); // Should always be called, to initialize a fresh WebPAnimDecoderOptions // structure before modification. Returns false in case of version mismatch. // WebPAnimDecoderOptionsInit() must have succeeded before using the // 'dec_options' object. static WEBP_INLINE int WebPAnimDecoderOptionsInit( WebPAnimDecoderOptions* dec_options) { return WebPAnimDecoderOptionsInitInternal(dec_options, WEBP_DEMUX_ABI_VERSION); } // Internal, version-checked, entry point. WEBP_EXTERN WebPAnimDecoder* WebPAnimDecoderNewInternal( const WebPData*, const WebPAnimDecoderOptions*, int); // Creates and initializes a WebPAnimDecoder object. // Parameters: // webp_data - (in) WebP bitstream. This should remain unchanged during the // lifetime of the output WebPAnimDecoder object. // dec_options - (in) decoding options. Can be passed NULL to choose // reasonable defaults (in particular, color mode MODE_RGBA // will be picked). // Returns: // A pointer to the newly created WebPAnimDecoder object, or NULL in case of // parsing error, invalid option or memory error. static WEBP_INLINE WebPAnimDecoder* WebPAnimDecoderNew( const WebPData* webp_data, const WebPAnimDecoderOptions* dec_options) { return WebPAnimDecoderNewInternal(webp_data, dec_options, WEBP_DEMUX_ABI_VERSION); } // Global information about the animation.. struct WebPAnimInfo { uint32_t canvas_width; uint32_t canvas_height; uint32_t loop_count; uint32_t bgcolor; uint32_t frame_count; uint32_t pad[4]; // padding for later use }; // Get global information about the animation. // Parameters: // dec - (in) decoder instance to get information from. // info - (out) global information fetched from the animation. // Returns: // True on success. WEBP_EXTERN int WebPAnimDecoderGetInfo(const WebPAnimDecoder* dec, WebPAnimInfo* info); // Fetch the next frame from 'dec' based on options supplied to // WebPAnimDecoderNew(). This will be a fully reconstructed canvas of size // 'canvas_width * 4 * canvas_height', and not just the frame sub-rectangle. The // returned buffer 'buf' is valid only until the next call to // WebPAnimDecoderGetNext(), WebPAnimDecoderReset() or WebPAnimDecoderDelete(). // Parameters: // dec - (in/out) decoder instance from which the next frame is to be fetched. // buf - (out) decoded frame. // timestamp - (out) timestamp of the frame in milliseconds. // Returns: // False if any of the arguments are NULL, or if there is a parsing or // decoding error, or if there are no more frames. Otherwise, returns true. WEBP_EXTERN int WebPAnimDecoderGetNext(WebPAnimDecoder* dec, uint8_t** buf, int* timestamp); // Check if there are more frames left to decode. // Parameters: // dec - (in) decoder instance to be checked. // Returns: // True if 'dec' is not NULL and some frames are yet to be decoded. // Otherwise, returns false. WEBP_EXTERN int WebPAnimDecoderHasMoreFrames(const WebPAnimDecoder* dec); // Resets the WebPAnimDecoder object, so that next call to // WebPAnimDecoderGetNext() will restart decoding from 1st frame. This would be // helpful when all frames need to be decoded multiple times (e.g. // info.loop_count times) without destroying and recreating the 'dec' object. // Parameters: // dec - (in/out) decoder instance to be reset WEBP_EXTERN void WebPAnimDecoderReset(WebPAnimDecoder* dec); // Grab the internal demuxer object. // Getting the demuxer object can be useful if one wants to use operations only // available through demuxer; e.g. to get XMP/EXIF/ICC metadata. The returned // demuxer object is owned by 'dec' and is valid only until the next call to // WebPAnimDecoderDelete(). // // Parameters: // dec - (in) decoder instance from which the demuxer object is to be fetched. WEBP_EXTERN const WebPDemuxer* WebPAnimDecoderGetDemuxer( const WebPAnimDecoder* dec); // Deletes the WebPAnimDecoder object. // Parameters: // dec - (in/out) decoder instance to be deleted WEBP_EXTERN void WebPAnimDecoderDelete(WebPAnimDecoder* dec); #ifdef __cplusplus } // extern "C" #endif #endif /* WEBP_WEBP_DEMUX_H_ */