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Diffstat (limited to 'media/libwebp/src/webp/decode.h')
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1 files changed, 503 insertions, 0 deletions
diff --git a/media/libwebp/src/webp/decode.h b/media/libwebp/src/webp/decode.h new file mode 100644 index 0000000000..d98247509a --- /dev/null +++ b/media/libwebp/src/webp/decode.h @@ -0,0 +1,503 @@ +// Copyright 2010 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. +// ----------------------------------------------------------------------------- +// +// Main decoding functions for WebP images. +// +// Author: Skal (pascal.massimino@gmail.com) + +#ifndef WEBP_WEBP_DECODE_H_ +#define WEBP_WEBP_DECODE_H_ + +#include "./types.h" + +#ifdef __cplusplus +extern "C" { +#endif + +#define WEBP_DECODER_ABI_VERSION 0x0209 // 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 VP8StatusCode VP8StatusCode; +// typedef enum WEBP_CSP_MODE WEBP_CSP_MODE; +typedef struct WebPRGBABuffer WebPRGBABuffer; +typedef struct WebPYUVABuffer WebPYUVABuffer; +typedef struct WebPDecBuffer WebPDecBuffer; +typedef struct WebPIDecoder WebPIDecoder; +typedef struct WebPBitstreamFeatures WebPBitstreamFeatures; +typedef struct WebPDecoderOptions WebPDecoderOptions; +typedef struct WebPDecoderConfig WebPDecoderConfig; + +// Return the decoder's version number, packed in hexadecimal using 8bits for +// each of major/minor/revision. E.g: v2.5.7 is 0x020507. +WEBP_EXTERN int WebPGetDecoderVersion(void); + +// Retrieve basic header information: width, height. +// This function will also validate the header, returning true on success, +// false otherwise. '*width' and '*height' are only valid on successful return. +// Pointers 'width' and 'height' can be passed NULL if deemed irrelevant. +// Note: The following chunk sequences (before the raw VP8/VP8L data) are +// considered valid by this function: +// RIFF + VP8(L) +// RIFF + VP8X + (optional chunks) + VP8(L) +// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose. +// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose. +WEBP_EXTERN int WebPGetInfo(const uint8_t* data, size_t data_size, + int* width, int* height); + +// Decodes WebP images pointed to by 'data' and returns RGBA samples, along +// with the dimensions in *width and *height. The ordering of samples in +// memory is R, G, B, A, R, G, B, A... in scan order (endian-independent). +// The returned pointer should be deleted calling WebPFree(). +// Returns NULL in case of error. +WEBP_EXTERN uint8_t* WebPDecodeRGBA(const uint8_t* data, size_t data_size, + int* width, int* height); + +// Same as WebPDecodeRGBA, but returning A, R, G, B, A, R, G, B... ordered data. +WEBP_EXTERN uint8_t* WebPDecodeARGB(const uint8_t* data, size_t data_size, + int* width, int* height); + +// Same as WebPDecodeRGBA, but returning B, G, R, A, B, G, R, A... ordered data. +WEBP_EXTERN uint8_t* WebPDecodeBGRA(const uint8_t* data, size_t data_size, + int* width, int* height); + +// Same as WebPDecodeRGBA, but returning R, G, B, R, G, B... ordered data. +// If the bitstream contains transparency, it is ignored. +WEBP_EXTERN uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size, + int* width, int* height); + +// Same as WebPDecodeRGB, but returning B, G, R, B, G, R... ordered data. +WEBP_EXTERN uint8_t* WebPDecodeBGR(const uint8_t* data, size_t data_size, + int* width, int* height); + + +// Decode WebP images pointed to by 'data' to Y'UV format(*). The pointer +// returned is the Y samples buffer. Upon return, *u and *v will point to +// the U and V chroma data. These U and V buffers need NOT be passed to +// WebPFree(), unlike the returned Y luma one. The dimension of the U and V +// planes are both (*width + 1) / 2 and (*height + 1)/ 2. +// Upon return, the Y buffer has a stride returned as '*stride', while U and V +// have a common stride returned as '*uv_stride'. +// Return NULL in case of error. +// (*) Also named Y'CbCr. See: https://en.wikipedia.org/wiki/YCbCr +WEBP_EXTERN uint8_t* WebPDecodeYUV(const uint8_t* data, size_t data_size, + int* width, int* height, + uint8_t** u, uint8_t** v, + int* stride, int* uv_stride); + +// These five functions are variants of the above ones, that decode the image +// directly into a pre-allocated buffer 'output_buffer'. The maximum storage +// available in this buffer is indicated by 'output_buffer_size'. If this +// storage is not sufficient (or an error occurred), NULL is returned. +// Otherwise, output_buffer is returned, for convenience. +// The parameter 'output_stride' specifies the distance (in bytes) +// between scanlines. Hence, output_buffer_size is expected to be at least +// output_stride x picture-height. +WEBP_EXTERN uint8_t* WebPDecodeRGBAInto( + const uint8_t* data, size_t data_size, + uint8_t* output_buffer, size_t output_buffer_size, int output_stride); +WEBP_EXTERN uint8_t* WebPDecodeARGBInto( + const uint8_t* data, size_t data_size, + uint8_t* output_buffer, size_t output_buffer_size, int output_stride); +WEBP_EXTERN uint8_t* WebPDecodeBGRAInto( + const uint8_t* data, size_t data_size, + uint8_t* output_buffer, size_t output_buffer_size, int output_stride); + +// RGB and BGR variants. Here too the transparency information, if present, +// will be dropped and ignored. +WEBP_EXTERN uint8_t* WebPDecodeRGBInto( + const uint8_t* data, size_t data_size, + uint8_t* output_buffer, size_t output_buffer_size, int output_stride); +WEBP_EXTERN uint8_t* WebPDecodeBGRInto( + const uint8_t* data, size_t data_size, + uint8_t* output_buffer, size_t output_buffer_size, int output_stride); + +// WebPDecodeYUVInto() is a variant of WebPDecodeYUV() that operates directly +// into pre-allocated luma/chroma plane buffers. This function requires the +// strides to be passed: one for the luma plane and one for each of the +// chroma ones. The size of each plane buffer is passed as 'luma_size', +// 'u_size' and 'v_size' respectively. +// Pointer to the luma plane ('*luma') is returned or NULL if an error occurred +// during decoding (or because some buffers were found to be too small). +WEBP_EXTERN uint8_t* WebPDecodeYUVInto( + const uint8_t* data, size_t data_size, + uint8_t* luma, size_t luma_size, int luma_stride, + uint8_t* u, size_t u_size, int u_stride, + uint8_t* v, size_t v_size, int v_stride); + +//------------------------------------------------------------------------------ +// Output colorspaces and buffer + +// Colorspaces +// Note: the naming describes the byte-ordering of packed samples in memory. +// For instance, MODE_BGRA relates to samples ordered as B,G,R,A,B,G,R,A,... +// Non-capital names (e.g.:MODE_Argb) relates to pre-multiplied RGB channels. +// RGBA-4444 and RGB-565 colorspaces are represented by following byte-order: +// RGBA-4444: [r3 r2 r1 r0 g3 g2 g1 g0], [b3 b2 b1 b0 a3 a2 a1 a0], ... +// RGB-565: [r4 r3 r2 r1 r0 g5 g4 g3], [g2 g1 g0 b4 b3 b2 b1 b0], ... +// In the case WEBP_SWAP_16BITS_CSP is defined, the bytes are swapped for +// these two modes: +// RGBA-4444: [b3 b2 b1 b0 a3 a2 a1 a0], [r3 r2 r1 r0 g3 g2 g1 g0], ... +// RGB-565: [g2 g1 g0 b4 b3 b2 b1 b0], [r4 r3 r2 r1 r0 g5 g4 g3], ... + +typedef enum WEBP_CSP_MODE { + MODE_RGB = 0, MODE_RGBA = 1, + MODE_BGR = 2, MODE_BGRA = 3, + MODE_ARGB = 4, MODE_RGBA_4444 = 5, + MODE_RGB_565 = 6, + // RGB-premultiplied transparent modes (alpha value is preserved) + MODE_rgbA = 7, + MODE_bgrA = 8, + MODE_Argb = 9, + MODE_rgbA_4444 = 10, + // YUV modes must come after RGB ones. + MODE_YUV = 11, MODE_YUVA = 12, // yuv 4:2:0 + MODE_LAST = 13 +} WEBP_CSP_MODE; + +// Some useful macros: +static WEBP_INLINE int WebPIsPremultipliedMode(WEBP_CSP_MODE mode) { + return (mode == MODE_rgbA || mode == MODE_bgrA || mode == MODE_Argb || + mode == MODE_rgbA_4444); +} + +static WEBP_INLINE int WebPIsAlphaMode(WEBP_CSP_MODE mode) { + return (mode == MODE_RGBA || mode == MODE_BGRA || mode == MODE_ARGB || + mode == MODE_RGBA_4444 || mode == MODE_YUVA || + WebPIsPremultipliedMode(mode)); +} + +static WEBP_INLINE int WebPIsRGBMode(WEBP_CSP_MODE mode) { + return (mode < MODE_YUV); +} + +//------------------------------------------------------------------------------ +// WebPDecBuffer: Generic structure for describing the output sample buffer. + +struct WebPRGBABuffer { // view as RGBA + uint8_t* rgba; // pointer to RGBA samples + int stride; // stride in bytes from one scanline to the next. + size_t size; // total size of the *rgba buffer. +}; + +struct WebPYUVABuffer { // view as YUVA + uint8_t* y, *u, *v, *a; // pointer to luma, chroma U/V, alpha samples + int y_stride; // luma stride + int u_stride, v_stride; // chroma strides + int a_stride; // alpha stride + size_t y_size; // luma plane size + size_t u_size, v_size; // chroma planes size + size_t a_size; // alpha-plane size +}; + +// Output buffer +struct WebPDecBuffer { + WEBP_CSP_MODE colorspace; // Colorspace. + int width, height; // Dimensions. + int is_external_memory; // If non-zero, 'internal_memory' pointer is not + // used. If value is '2' or more, the external + // memory is considered 'slow' and multiple + // read/write will be avoided. + union { + WebPRGBABuffer RGBA; + WebPYUVABuffer YUVA; + } u; // Nameless union of buffer parameters. + uint32_t pad[4]; // padding for later use + + uint8_t* private_memory; // Internally allocated memory (only when + // is_external_memory is 0). Should not be used + // externally, but accessed via the buffer union. +}; + +// Internal, version-checked, entry point +WEBP_EXTERN int WebPInitDecBufferInternal(WebPDecBuffer*, int); + +// Initialize the structure as empty. Must be called before any other use. +// Returns false in case of version mismatch +static WEBP_INLINE int WebPInitDecBuffer(WebPDecBuffer* buffer) { + return WebPInitDecBufferInternal(buffer, WEBP_DECODER_ABI_VERSION); +} + +// Free any memory associated with the buffer. Must always be called last. +// Note: doesn't free the 'buffer' structure itself. +WEBP_EXTERN void WebPFreeDecBuffer(WebPDecBuffer* buffer); + +//------------------------------------------------------------------------------ +// Enumeration of the status codes + +typedef enum VP8StatusCode { + VP8_STATUS_OK = 0, + VP8_STATUS_OUT_OF_MEMORY, + VP8_STATUS_INVALID_PARAM, + VP8_STATUS_BITSTREAM_ERROR, + VP8_STATUS_UNSUPPORTED_FEATURE, + VP8_STATUS_SUSPENDED, + VP8_STATUS_USER_ABORT, + VP8_STATUS_NOT_ENOUGH_DATA +} VP8StatusCode; + +//------------------------------------------------------------------------------ +// Incremental decoding +// +// This API allows streamlined decoding of partial data. +// Picture can be incrementally decoded as data become available thanks to the +// WebPIDecoder object. This object can be left in a SUSPENDED state if the +// picture is only partially decoded, pending additional input. +// Code example: +// +// WebPInitDecBuffer(&output_buffer); +// output_buffer.colorspace = mode; +// ... +// WebPIDecoder* idec = WebPINewDecoder(&output_buffer); +// while (additional_data_is_available) { +// // ... (get additional data in some new_data[] buffer) +// status = WebPIAppend(idec, new_data, new_data_size); +// if (status != VP8_STATUS_OK && status != VP8_STATUS_SUSPENDED) { +// break; // an error occurred. +// } +// +// // The above call decodes the current available buffer. +// // Part of the image can now be refreshed by calling +// // WebPIDecGetRGB()/WebPIDecGetYUVA() etc. +// } +// WebPIDelete(idec); + +// Creates a new incremental decoder with the supplied buffer parameter. +// This output_buffer can be passed NULL, in which case a default output buffer +// is used (with MODE_RGB). Otherwise, an internal reference to 'output_buffer' +// is kept, which means that the lifespan of 'output_buffer' must be larger than +// that of the returned WebPIDecoder object. +// The supplied 'output_buffer' content MUST NOT be changed between calls to +// WebPIAppend() or WebPIUpdate() unless 'output_buffer.is_external_memory' is +// not set to 0. In such a case, it is allowed to modify the pointers, size and +// stride of output_buffer.u.RGBA or output_buffer.u.YUVA, provided they remain +// within valid bounds. +// All other fields of WebPDecBuffer MUST remain constant between calls. +// Returns NULL if the allocation failed. +WEBP_EXTERN WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer); + +// This function allocates and initializes an incremental-decoder object, which +// will output the RGB/A samples specified by 'csp' into a preallocated +// buffer 'output_buffer'. The size of this buffer is at least +// 'output_buffer_size' and the stride (distance in bytes between two scanlines) +// is specified by 'output_stride'. +// Additionally, output_buffer can be passed NULL in which case the output +// buffer will be allocated automatically when the decoding starts. The +// colorspace 'csp' is taken into account for allocating this buffer. All other +// parameters are ignored. +// Returns NULL if the allocation failed, or if some parameters are invalid. +WEBP_EXTERN WebPIDecoder* WebPINewRGB( + WEBP_CSP_MODE csp, + uint8_t* output_buffer, size_t output_buffer_size, int output_stride); + +// This function allocates and initializes an incremental-decoder object, which +// will output the raw luma/chroma samples into a preallocated planes if +// supplied. The luma plane is specified by its pointer 'luma', its size +// 'luma_size' and its stride 'luma_stride'. Similarly, the chroma-u plane +// is specified by the 'u', 'u_size' and 'u_stride' parameters, and the chroma-v +// plane by 'v' and 'v_size'. And same for the alpha-plane. The 'a' pointer +// can be pass NULL in case one is not interested in the transparency plane. +// Conversely, 'luma' can be passed NULL if no preallocated planes are supplied. +// In this case, the output buffer will be automatically allocated (using +// MODE_YUVA) when decoding starts. All parameters are then ignored. +// Returns NULL if the allocation failed or if a parameter is invalid. +WEBP_EXTERN WebPIDecoder* WebPINewYUVA( + uint8_t* luma, size_t luma_size, int luma_stride, + uint8_t* u, size_t u_size, int u_stride, + uint8_t* v, size_t v_size, int v_stride, + uint8_t* a, size_t a_size, int a_stride); + +// Deprecated version of the above, without the alpha plane. +// Kept for backward compatibility. +WEBP_EXTERN WebPIDecoder* WebPINewYUV( + uint8_t* luma, size_t luma_size, int luma_stride, + uint8_t* u, size_t u_size, int u_stride, + uint8_t* v, size_t v_size, int v_stride); + +// Deletes the WebPIDecoder object and associated memory. Must always be called +// if WebPINewDecoder, WebPINewRGB or WebPINewYUV succeeded. +WEBP_EXTERN void WebPIDelete(WebPIDecoder* idec); + +// Copies and decodes the next available data. Returns VP8_STATUS_OK when +// the image is successfully decoded. Returns VP8_STATUS_SUSPENDED when more +// data is expected. Returns error in other cases. +WEBP_EXTERN VP8StatusCode WebPIAppend( + WebPIDecoder* idec, const uint8_t* data, size_t data_size); + +// A variant of the above function to be used when data buffer contains +// partial data from the beginning. In this case data buffer is not copied +// to the internal memory. +// Note that the value of the 'data' pointer can change between calls to +// WebPIUpdate, for instance when the data buffer is resized to fit larger data. +WEBP_EXTERN VP8StatusCode WebPIUpdate( + WebPIDecoder* idec, const uint8_t* data, size_t data_size); + +// Returns the RGB/A image decoded so far. Returns NULL if output params +// are not initialized yet. The RGB/A output type corresponds to the colorspace +// specified during call to WebPINewDecoder() or WebPINewRGB(). +// *last_y is the index of last decoded row in raster scan order. Some pointers +// (*last_y, *width etc.) can be NULL if corresponding information is not +// needed. The values in these pointers are only valid on successful (non-NULL) +// return. +WEBP_EXTERN uint8_t* WebPIDecGetRGB( + const WebPIDecoder* idec, int* last_y, + int* width, int* height, int* stride); + +// Same as above function to get a YUVA image. Returns pointer to the luma +// plane or NULL in case of error. If there is no alpha information +// the alpha pointer '*a' will be returned NULL. +WEBP_EXTERN uint8_t* WebPIDecGetYUVA( + const WebPIDecoder* idec, int* last_y, + uint8_t** u, uint8_t** v, uint8_t** a, + int* width, int* height, int* stride, int* uv_stride, int* a_stride); + +// Deprecated alpha-less version of WebPIDecGetYUVA(): it will ignore the +// alpha information (if present). Kept for backward compatibility. +static WEBP_INLINE uint8_t* WebPIDecGetYUV( + const WebPIDecoder* idec, int* last_y, uint8_t** u, uint8_t** v, + int* width, int* height, int* stride, int* uv_stride) { + return WebPIDecGetYUVA(idec, last_y, u, v, NULL, width, height, + stride, uv_stride, NULL); +} + +// Generic call to retrieve information about the displayable area. +// If non NULL, the left/right/width/height pointers are filled with the visible +// rectangular area so far. +// Returns NULL in case the incremental decoder object is in an invalid state. +// Otherwise returns the pointer to the internal representation. This structure +// is read-only, tied to WebPIDecoder's lifespan and should not be modified. +WEBP_EXTERN const WebPDecBuffer* WebPIDecodedArea( + const WebPIDecoder* idec, int* left, int* top, int* width, int* height); + +//------------------------------------------------------------------------------ +// Advanced decoding parametrization +// +// Code sample for using the advanced decoding API +/* + // A) Init a configuration object + WebPDecoderConfig config; + CHECK(WebPInitDecoderConfig(&config)); + + // B) optional: retrieve the bitstream's features. + CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK); + + // C) Adjust 'config', if needed + config.no_fancy_upsampling = 1; + config.output.colorspace = MODE_BGRA; + // etc. + + // Note that you can also make config.output point to an externally + // supplied memory buffer, provided it's big enough to store the decoded + // picture. Otherwise, config.output will just be used to allocate memory + // and store the decoded picture. + + // D) Decode! + CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK); + + // E) Decoded image is now in config.output (and config.output.u.RGBA) + + // F) Reclaim memory allocated in config's object. It's safe to call + // this function even if the memory is external and wasn't allocated + // by WebPDecode(). + WebPFreeDecBuffer(&config.output); +*/ + +// Features gathered from the bitstream +struct WebPBitstreamFeatures { + int width; // Width in pixels, as read from the bitstream. + int height; // Height in pixels, as read from the bitstream. + int has_alpha; // True if the bitstream contains an alpha channel. + int has_animation; // True if the bitstream is an animation. + int format; // 0 = undefined (/mixed), 1 = lossy, 2 = lossless + + uint32_t pad[5]; // padding for later use +}; + +// Internal, version-checked, entry point +WEBP_EXTERN VP8StatusCode WebPGetFeaturesInternal( + const uint8_t*, size_t, WebPBitstreamFeatures*, int); + +// Retrieve features from the bitstream. The *features structure is filled +// with information gathered from the bitstream. +// Returns VP8_STATUS_OK when the features are successfully retrieved. Returns +// VP8_STATUS_NOT_ENOUGH_DATA when more data is needed to retrieve the +// features from headers. Returns error in other cases. +// Note: The following chunk sequences (before the raw VP8/VP8L data) are +// considered valid by this function: +// RIFF + VP8(L) +// RIFF + VP8X + (optional chunks) + VP8(L) +// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose. +// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose. +static WEBP_INLINE VP8StatusCode WebPGetFeatures( + const uint8_t* data, size_t data_size, + WebPBitstreamFeatures* features) { + return WebPGetFeaturesInternal(data, data_size, features, + WEBP_DECODER_ABI_VERSION); +} + +// Decoding options +struct WebPDecoderOptions { + int bypass_filtering; // if true, skip the in-loop filtering + int no_fancy_upsampling; // if true, use faster pointwise upsampler + int use_cropping; // if true, cropping is applied _first_ + int crop_left, crop_top; // top-left position for cropping. + // Will be snapped to even values. + int crop_width, crop_height; // dimension of the cropping area + int use_scaling; // if true, scaling is applied _afterward_ + int scaled_width, scaled_height; // final resolution + int use_threads; // if true, use multi-threaded decoding + int dithering_strength; // dithering strength (0=Off, 100=full) + int flip; // if true, flip output vertically + int alpha_dithering_strength; // alpha dithering strength in [0..100] + + uint32_t pad[5]; // padding for later use +}; + +// Main object storing the configuration for advanced decoding. +struct WebPDecoderConfig { + WebPBitstreamFeatures input; // Immutable bitstream features (optional) + WebPDecBuffer output; // Output buffer (can point to external mem) + WebPDecoderOptions options; // Decoding options +}; + +// Internal, version-checked, entry point +WEBP_EXTERN int WebPInitDecoderConfigInternal(WebPDecoderConfig*, int); + +// Initialize the configuration as empty. This function must always be +// called first, unless WebPGetFeatures() is to be called. +// Returns false in case of mismatched version. +static WEBP_INLINE int WebPInitDecoderConfig(WebPDecoderConfig* config) { + return WebPInitDecoderConfigInternal(config, WEBP_DECODER_ABI_VERSION); +} + +// Instantiate a new incremental decoder object with the requested +// configuration. The bitstream can be passed using 'data' and 'data_size' +// parameter, in which case the features will be parsed and stored into +// config->input. Otherwise, 'data' can be NULL and no parsing will occur. +// Note that 'config' can be NULL too, in which case a default configuration +// is used. If 'config' is not NULL, it must outlive the WebPIDecoder object +// as some references to its fields will be used. No internal copy of 'config' +// is made. +// The return WebPIDecoder object must always be deleted calling WebPIDelete(). +// Returns NULL in case of error (and config->status will then reflect +// the error condition, if available). +WEBP_EXTERN WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size, + WebPDecoderConfig* config); + +// Non-incremental version. This version decodes the full data at once, taking +// 'config' into account. Returns decoding status (which should be VP8_STATUS_OK +// if the decoding was successful). Note that 'config' cannot be NULL. +WEBP_EXTERN VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size, + WebPDecoderConfig* config); + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif // WEBP_WEBP_DECODE_H_ |