1// Copyright 2010 Google Inc. All Rights Reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the COPYING file in the root of the source
5// tree. An additional intellectual property rights grant can be found
6// in the file PATENTS. All contributing project authors may
7// be found in the AUTHORS file in the root of the source tree.
8// -----------------------------------------------------------------------------
9//
10// Main decoding functions for WebP images.
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#ifndef WEBP_WEBP_DECODE_H_
15#define WEBP_WEBP_DECODE_H_
16
17#include "./types.h"
18
19#ifdef __cplusplus
20extern "C" {
21#endif
22
23#define WEBP_DECODER_ABI_VERSION 0x0209 // MAJOR(8b) + MINOR(8b)
24
25// Note: forward declaring enumerations is not allowed in (strict) C and C++,
26// the types are left here for reference.
27// typedef enum VP8StatusCode VP8StatusCode;
28// typedef enum WEBP_CSP_MODE WEBP_CSP_MODE;
29typedef struct WebPRGBABuffer WebPRGBABuffer;
30typedef struct WebPYUVABuffer WebPYUVABuffer;
31typedef struct WebPDecBuffer WebPDecBuffer;
32typedef struct WebPIDecoder WebPIDecoder;
33typedef struct WebPBitstreamFeatures WebPBitstreamFeatures;
34typedef struct WebPDecoderOptions WebPDecoderOptions;
35typedef struct WebPDecoderConfig WebPDecoderConfig;
36
37// Return the decoder's version number, packed in hexadecimal using 8bits for
38// each of major/minor/revision. E.g: v2.5.7 is 0x020507.
39WEBP_EXTERN int WebPGetDecoderVersion(void);
40
41// Retrieve basic header information: width, height.
42// This function will also validate the header, returning true on success,
43// false otherwise. '*width' and '*height' are only valid on successful return.
44// Pointers 'width' and 'height' can be passed NULL if deemed irrelevant.
45// Note: The following chunk sequences (before the raw VP8/VP8L data) are
46// considered valid by this function:
47// RIFF + VP8(L)
48// RIFF + VP8X + (optional chunks) + VP8(L)
49// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
50// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose.
51WEBP_EXTERN int WebPGetInfo(const uint8_t* data, size_t data_size,
52 int* width, int* height);
53
54// Decodes WebP images pointed to by 'data' and returns RGBA samples, along
55// with the dimensions in *width and *height. The ordering of samples in
56// memory is R, G, B, A, R, G, B, A... in scan order (endian-independent).
57// The returned pointer should be deleted calling WebPFree().
58// Returns NULL in case of error.
59WEBP_EXTERN uint8_t* WebPDecodeRGBA(const uint8_t* data, size_t data_size,
60 int* width, int* height);
61
62// Same as WebPDecodeRGBA, but returning A, R, G, B, A, R, G, B... ordered data.
63WEBP_EXTERN uint8_t* WebPDecodeARGB(const uint8_t* data, size_t data_size,
64 int* width, int* height);
65
66// Same as WebPDecodeRGBA, but returning B, G, R, A, B, G, R, A... ordered data.
67WEBP_EXTERN uint8_t* WebPDecodeBGRA(const uint8_t* data, size_t data_size,
68 int* width, int* height);
69
70// Same as WebPDecodeRGBA, but returning R, G, B, R, G, B... ordered data.
71// If the bitstream contains transparency, it is ignored.
72WEBP_EXTERN uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
73 int* width, int* height);
74
75// Same as WebPDecodeRGB, but returning B, G, R, B, G, R... ordered data.
76WEBP_EXTERN uint8_t* WebPDecodeBGR(const uint8_t* data, size_t data_size,
77 int* width, int* height);
78
79
80// Decode WebP images pointed to by 'data' to Y'UV format(*). The pointer
81// returned is the Y samples buffer. Upon return, *u and *v will point to
82// the U and V chroma data. These U and V buffers need NOT be passed to
83// WebPFree(), unlike the returned Y luma one. The dimension of the U and V
84// planes are both (*width + 1) / 2 and (*height + 1)/ 2.
85// Upon return, the Y buffer has a stride returned as '*stride', while U and V
86// have a common stride returned as '*uv_stride'.
87// Return NULL in case of error.
88// (*) Also named Y'CbCr. See: https://en.wikipedia.org/wiki/YCbCr
89WEBP_EXTERN uint8_t* WebPDecodeYUV(const uint8_t* data, size_t data_size,
90 int* width, int* height,
91 uint8_t** u, uint8_t** v,
92 int* stride, int* uv_stride);
93
94// These five functions are variants of the above ones, that decode the image
95// directly into a pre-allocated buffer 'output_buffer'. The maximum storage
96// available in this buffer is indicated by 'output_buffer_size'. If this
97// storage is not sufficient (or an error occurred), NULL is returned.
98// Otherwise, output_buffer is returned, for convenience.
99// The parameter 'output_stride' specifies the distance (in bytes)
100// between scanlines. Hence, output_buffer_size is expected to be at least
101// output_stride x picture-height.
102WEBP_EXTERN uint8_t* WebPDecodeRGBAInto(
103 const uint8_t* data, size_t data_size,
104 uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
105WEBP_EXTERN uint8_t* WebPDecodeARGBInto(
106 const uint8_t* data, size_t data_size,
107 uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
108WEBP_EXTERN uint8_t* WebPDecodeBGRAInto(
109 const uint8_t* data, size_t data_size,
110 uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
111
112// RGB and BGR variants. Here too the transparency information, if present,
113// will be dropped and ignored.
114WEBP_EXTERN uint8_t* WebPDecodeRGBInto(
115 const uint8_t* data, size_t data_size,
116 uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
117WEBP_EXTERN uint8_t* WebPDecodeBGRInto(
118 const uint8_t* data, size_t data_size,
119 uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
120
121// WebPDecodeYUVInto() is a variant of WebPDecodeYUV() that operates directly
122// into pre-allocated luma/chroma plane buffers. This function requires the
123// strides to be passed: one for the luma plane and one for each of the
124// chroma ones. The size of each plane buffer is passed as 'luma_size',
125// 'u_size' and 'v_size' respectively.
126// Pointer to the luma plane ('*luma') is returned or NULL if an error occurred
127// during decoding (or because some buffers were found to be too small).
128WEBP_EXTERN uint8_t* WebPDecodeYUVInto(
129 const uint8_t* data, size_t data_size,
130 uint8_t* luma, size_t luma_size, int luma_stride,
131 uint8_t* u, size_t u_size, int u_stride,
132 uint8_t* v, size_t v_size, int v_stride);
133
134//------------------------------------------------------------------------------
135// Output colorspaces and buffer
136
137// Colorspaces
138// Note: the naming describes the byte-ordering of packed samples in memory.
139// For instance, MODE_BGRA relates to samples ordered as B,G,R,A,B,G,R,A,...
140// Non-capital names (e.g.:MODE_Argb) relates to pre-multiplied RGB channels.
141// RGBA-4444 and RGB-565 colorspaces are represented by following byte-order:
142// RGBA-4444: [r3 r2 r1 r0 g3 g2 g1 g0], [b3 b2 b1 b0 a3 a2 a1 a0], ...
143// RGB-565: [r4 r3 r2 r1 r0 g5 g4 g3], [g2 g1 g0 b4 b3 b2 b1 b0], ...
144// In the case WEBP_SWAP_16BITS_CSP is defined, the bytes are swapped for
145// these two modes:
146// RGBA-4444: [b3 b2 b1 b0 a3 a2 a1 a0], [r3 r2 r1 r0 g3 g2 g1 g0], ...
147// RGB-565: [g2 g1 g0 b4 b3 b2 b1 b0], [r4 r3 r2 r1 r0 g5 g4 g3], ...
148
149typedef enum WEBP_CSP_MODE {
150 MODE_RGB = 0, MODE_RGBA = 1,
151 MODE_BGR = 2, MODE_BGRA = 3,
152 MODE_ARGB = 4, MODE_RGBA_4444 = 5,
153 MODE_RGB_565 = 6,
154 // RGB-premultiplied transparent modes (alpha value is preserved)
155 MODE_rgbA = 7,
156 MODE_bgrA = 8,
157 MODE_Argb = 9,
158 MODE_rgbA_4444 = 10,
159 // YUV modes must come after RGB ones.
160 MODE_YUV = 11, MODE_YUVA = 12, // yuv 4:2:0
161 MODE_LAST = 13
162} WEBP_CSP_MODE;
163
164// Some useful macros:
165static WEBP_INLINE int WebPIsPremultipliedMode(WEBP_CSP_MODE mode) {
166 return (mode == MODE_rgbA || mode == MODE_bgrA || mode == MODE_Argb ||
167 mode == MODE_rgbA_4444);
168}
169
170static WEBP_INLINE int WebPIsAlphaMode(WEBP_CSP_MODE mode) {
171 return (mode == MODE_RGBA || mode == MODE_BGRA || mode == MODE_ARGB ||
172 mode == MODE_RGBA_4444 || mode == MODE_YUVA ||
173 WebPIsPremultipliedMode(mode));
174}
175
176static WEBP_INLINE int WebPIsRGBMode(WEBP_CSP_MODE mode) {
177 return (mode < MODE_YUV);
178}
179
180//------------------------------------------------------------------------------
181// WebPDecBuffer: Generic structure for describing the output sample buffer.
182
183struct WebPRGBABuffer { // view as RGBA
184 uint8_t* rgba; // pointer to RGBA samples
185 int stride; // stride in bytes from one scanline to the next.
186 size_t size; // total size of the *rgba buffer.
187};
188
189struct WebPYUVABuffer { // view as YUVA
190 uint8_t* y, *u, *v, *a; // pointer to luma, chroma U/V, alpha samples
191 int y_stride; // luma stride
192 int u_stride, v_stride; // chroma strides
193 int a_stride; // alpha stride
194 size_t y_size; // luma plane size
195 size_t u_size, v_size; // chroma planes size
196 size_t a_size; // alpha-plane size
197};
198
199// Output buffer
200struct WebPDecBuffer {
201 WEBP_CSP_MODE colorspace; // Colorspace.
202 int width, height; // Dimensions.
203 int is_external_memory; // If non-zero, 'internal_memory' pointer is not
204 // used. If value is '2' or more, the external
205 // memory is considered 'slow' and multiple
206 // read/write will be avoided.
207 union {
208 WebPRGBABuffer RGBA;
209 WebPYUVABuffer YUVA;
210 } u; // Nameless union of buffer parameters.
211 uint32_t pad[4]; // padding for later use
212
213 uint8_t* private_memory; // Internally allocated memory (only when
214 // is_external_memory is 0). Should not be used
215 // externally, but accessed via the buffer union.
216};
217
218// Internal, version-checked, entry point
219WEBP_EXTERN int WebPInitDecBufferInternal(WebPDecBuffer*, int);
220
221// Initialize the structure as empty. Must be called before any other use.
222// Returns false in case of version mismatch
223static WEBP_INLINE int WebPInitDecBuffer(WebPDecBuffer* buffer) {
224 return WebPInitDecBufferInternal(buffer, WEBP_DECODER_ABI_VERSION);
225}
226
227// Free any memory associated with the buffer. Must always be called last.
228// Note: doesn't free the 'buffer' structure itself.
229WEBP_EXTERN void WebPFreeDecBuffer(WebPDecBuffer* buffer);
230
231//------------------------------------------------------------------------------
232// Enumeration of the status codes
233
234typedef enum VP8StatusCode {
235 VP8_STATUS_OK = 0,
236 VP8_STATUS_OUT_OF_MEMORY,
237 VP8_STATUS_INVALID_PARAM,
238 VP8_STATUS_BITSTREAM_ERROR,
239 VP8_STATUS_UNSUPPORTED_FEATURE,
240 VP8_STATUS_SUSPENDED,
241 VP8_STATUS_USER_ABORT,
242 VP8_STATUS_NOT_ENOUGH_DATA
243} VP8StatusCode;
244
245//------------------------------------------------------------------------------
246// Incremental decoding
247//
248// This API allows streamlined decoding of partial data.
249// Picture can be incrementally decoded as data become available thanks to the
250// WebPIDecoder object. This object can be left in a SUSPENDED state if the
251// picture is only partially decoded, pending additional input.
252// Code example:
253//
254// WebPInitDecBuffer(&output_buffer);
255// output_buffer.colorspace = mode;
256// ...
257// WebPIDecoder* idec = WebPINewDecoder(&output_buffer);
258// while (additional_data_is_available) {
259// // ... (get additional data in some new_data[] buffer)
260// status = WebPIAppend(idec, new_data, new_data_size);
261// if (status != VP8_STATUS_OK && status != VP8_STATUS_SUSPENDED) {
262// break; // an error occurred.
263// }
264//
265// // The above call decodes the current available buffer.
266// // Part of the image can now be refreshed by calling
267// // WebPIDecGetRGB()/WebPIDecGetYUVA() etc.
268// }
269// WebPIDelete(idec);
270
271// Creates a new incremental decoder with the supplied buffer parameter.
272// This output_buffer can be passed NULL, in which case a default output buffer
273// is used (with MODE_RGB). Otherwise, an internal reference to 'output_buffer'
274// is kept, which means that the lifespan of 'output_buffer' must be larger than
275// that of the returned WebPIDecoder object.
276// The supplied 'output_buffer' content MUST NOT be changed between calls to
277// WebPIAppend() or WebPIUpdate() unless 'output_buffer.is_external_memory' is
278// not set to 0. In such a case, it is allowed to modify the pointers, size and
279// stride of output_buffer.u.RGBA or output_buffer.u.YUVA, provided they remain
280// within valid bounds.
281// All other fields of WebPDecBuffer MUST remain constant between calls.
282// Returns NULL if the allocation failed.
283WEBP_EXTERN WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer);
284
285// This function allocates and initializes an incremental-decoder object, which
286// will output the RGB/A samples specified by 'csp' into a preallocated
287// buffer 'output_buffer'. The size of this buffer is at least
288// 'output_buffer_size' and the stride (distance in bytes between two scanlines)
289// is specified by 'output_stride'.
290// Additionally, output_buffer can be passed NULL in which case the output
291// buffer will be allocated automatically when the decoding starts. The
292// colorspace 'csp' is taken into account for allocating this buffer. All other
293// parameters are ignored.
294// Returns NULL if the allocation failed, or if some parameters are invalid.
295WEBP_EXTERN WebPIDecoder* WebPINewRGB(
296 WEBP_CSP_MODE csp,
297 uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
298
299// This function allocates and initializes an incremental-decoder object, which
300// will output the raw luma/chroma samples into a preallocated planes if
301// supplied. The luma plane is specified by its pointer 'luma', its size
302// 'luma_size' and its stride 'luma_stride'. Similarly, the chroma-u plane
303// is specified by the 'u', 'u_size' and 'u_stride' parameters, and the chroma-v
304// plane by 'v' and 'v_size'. And same for the alpha-plane. The 'a' pointer
305// can be pass NULL in case one is not interested in the transparency plane.
306// Conversely, 'luma' can be passed NULL if no preallocated planes are supplied.
307// In this case, the output buffer will be automatically allocated (using
308// MODE_YUVA) when decoding starts. All parameters are then ignored.
309// Returns NULL if the allocation failed or if a parameter is invalid.
310WEBP_EXTERN WebPIDecoder* WebPINewYUVA(
311 uint8_t* luma, size_t luma_size, int luma_stride,
312 uint8_t* u, size_t u_size, int u_stride,
313 uint8_t* v, size_t v_size, int v_stride,
314 uint8_t* a, size_t a_size, int a_stride);
315
316// Deprecated version of the above, without the alpha plane.
317// Kept for backward compatibility.
318WEBP_EXTERN WebPIDecoder* WebPINewYUV(
319 uint8_t* luma, size_t luma_size, int luma_stride,
320 uint8_t* u, size_t u_size, int u_stride,
321 uint8_t* v, size_t v_size, int v_stride);
322
323// Deletes the WebPIDecoder object and associated memory. Must always be called
324// if WebPINewDecoder, WebPINewRGB or WebPINewYUV succeeded.
325WEBP_EXTERN void WebPIDelete(WebPIDecoder* idec);
326
327// Copies and decodes the next available data. Returns VP8_STATUS_OK when
328// the image is successfully decoded. Returns VP8_STATUS_SUSPENDED when more
329// data is expected. Returns error in other cases.
330WEBP_EXTERN VP8StatusCode WebPIAppend(
331 WebPIDecoder* idec, const uint8_t* data, size_t data_size);
332
333// A variant of the above function to be used when data buffer contains
334// partial data from the beginning. In this case data buffer is not copied
335// to the internal memory.
336// Note that the value of the 'data' pointer can change between calls to
337// WebPIUpdate, for instance when the data buffer is resized to fit larger data.
338WEBP_EXTERN VP8StatusCode WebPIUpdate(
339 WebPIDecoder* idec, const uint8_t* data, size_t data_size);
340
341// Returns the RGB/A image decoded so far. Returns NULL if output params
342// are not initialized yet. The RGB/A output type corresponds to the colorspace
343// specified during call to WebPINewDecoder() or WebPINewRGB().
344// *last_y is the index of last decoded row in raster scan order. Some pointers
345// (*last_y, *width etc.) can be NULL if corresponding information is not
346// needed. The values in these pointers are only valid on successful (non-NULL)
347// return.
348WEBP_EXTERN uint8_t* WebPIDecGetRGB(
349 const WebPIDecoder* idec, int* last_y,
350 int* width, int* height, int* stride);
351
352// Same as above function to get a YUVA image. Returns pointer to the luma
353// plane or NULL in case of error. If there is no alpha information
354// the alpha pointer '*a' will be returned NULL.
355WEBP_EXTERN uint8_t* WebPIDecGetYUVA(
356 const WebPIDecoder* idec, int* last_y,
357 uint8_t** u, uint8_t** v, uint8_t** a,
358 int* width, int* height, int* stride, int* uv_stride, int* a_stride);
359
360// Deprecated alpha-less version of WebPIDecGetYUVA(): it will ignore the
361// alpha information (if present). Kept for backward compatibility.
362static WEBP_INLINE uint8_t* WebPIDecGetYUV(
363 const WebPIDecoder* idec, int* last_y, uint8_t** u, uint8_t** v,
364 int* width, int* height, int* stride, int* uv_stride) {
365 return WebPIDecGetYUVA(idec, last_y, u, v, NULL, width, height,
366 stride, uv_stride, NULL);
367}
368
369// Generic call to retrieve information about the displayable area.
370// If non NULL, the left/right/width/height pointers are filled with the visible
371// rectangular area so far.
372// Returns NULL in case the incremental decoder object is in an invalid state.
373// Otherwise returns the pointer to the internal representation. This structure
374// is read-only, tied to WebPIDecoder's lifespan and should not be modified.
375WEBP_EXTERN const WebPDecBuffer* WebPIDecodedArea(
376 const WebPIDecoder* idec, int* left, int* top, int* width, int* height);
377
378//------------------------------------------------------------------------------
379// Advanced decoding parametrization
380//
381// Code sample for using the advanced decoding API
382/*
383 // A) Init a configuration object
384 WebPDecoderConfig config;
385 CHECK(WebPInitDecoderConfig(&config));
386
387 // B) optional: retrieve the bitstream's features.
388 CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK);
389
390 // C) Adjust 'config', if needed
391 config.no_fancy_upsampling = 1;
392 config.output.colorspace = MODE_BGRA;
393 // etc.
394
395 // Note that you can also make config.output point to an externally
396 // supplied memory buffer, provided it's big enough to store the decoded
397 // picture. Otherwise, config.output will just be used to allocate memory
398 // and store the decoded picture.
399
400 // D) Decode!
401 CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK);
402
403 // E) Decoded image is now in config.output (and config.output.u.RGBA)
404
405 // F) Reclaim memory allocated in config's object. It's safe to call
406 // this function even if the memory is external and wasn't allocated
407 // by WebPDecode().
408 WebPFreeDecBuffer(&config.output);
409*/
410
411// Features gathered from the bitstream
412struct WebPBitstreamFeatures {
413 int width; // Width in pixels, as read from the bitstream.
414 int height; // Height in pixels, as read from the bitstream.
415 int has_alpha; // True if the bitstream contains an alpha channel.
416 int has_animation; // True if the bitstream is an animation.
417 int format; // 0 = undefined (/mixed), 1 = lossy, 2 = lossless
418
419 uint32_t pad[5]; // padding for later use
420};
421
422// Internal, version-checked, entry point
423WEBP_EXTERN VP8StatusCode WebPGetFeaturesInternal(
424 const uint8_t*, size_t, WebPBitstreamFeatures*, int);
425
426// Retrieve features from the bitstream. The *features structure is filled
427// with information gathered from the bitstream.
428// Returns VP8_STATUS_OK when the features are successfully retrieved. Returns
429// VP8_STATUS_NOT_ENOUGH_DATA when more data is needed to retrieve the
430// features from headers. Returns error in other cases.
431// Note: The following chunk sequences (before the raw VP8/VP8L data) are
432// considered valid by this function:
433// RIFF + VP8(L)
434// RIFF + VP8X + (optional chunks) + VP8(L)
435// ALPH + VP8 <-- Not a valid WebP format: only allowed for internal purpose.
436// VP8(L) <-- Not a valid WebP format: only allowed for internal purpose.
437static WEBP_INLINE VP8StatusCode WebPGetFeatures(
438 const uint8_t* data, size_t data_size,
439 WebPBitstreamFeatures* features) {
440 return WebPGetFeaturesInternal(data, data_size, features,
441 WEBP_DECODER_ABI_VERSION);
442}
443
444// Decoding options
445struct WebPDecoderOptions {
446 int bypass_filtering; // if true, skip the in-loop filtering
447 int no_fancy_upsampling; // if true, use faster pointwise upsampler
448 int use_cropping; // if true, cropping is applied _first_
449 int crop_left, crop_top; // top-left position for cropping.
450 // Will be snapped to even values.
451 int crop_width, crop_height; // dimension of the cropping area
452 int use_scaling; // if true, scaling is applied _afterward_
453 int scaled_width, scaled_height; // final resolution
454 int use_threads; // if true, use multi-threaded decoding
455 int dithering_strength; // dithering strength (0=Off, 100=full)
456 int flip; // if true, flip output vertically
457 int alpha_dithering_strength; // alpha dithering strength in [0..100]
458
459 uint32_t pad[5]; // padding for later use
460};
461
462// Main object storing the configuration for advanced decoding.
463struct WebPDecoderConfig {
464 WebPBitstreamFeatures input; // Immutable bitstream features (optional)
465 WebPDecBuffer output; // Output buffer (can point to external mem)
466 WebPDecoderOptions options; // Decoding options
467};
468
469// Internal, version-checked, entry point
470WEBP_EXTERN int WebPInitDecoderConfigInternal(WebPDecoderConfig*, int);
471
472// Initialize the configuration as empty. This function must always be
473// called first, unless WebPGetFeatures() is to be called.
474// Returns false in case of mismatched version.
475static WEBP_INLINE int WebPInitDecoderConfig(WebPDecoderConfig* config) {
476 return WebPInitDecoderConfigInternal(config, WEBP_DECODER_ABI_VERSION);
477}
478
479// Instantiate a new incremental decoder object with the requested
480// configuration. The bitstream can be passed using 'data' and 'data_size'
481// parameter, in which case the features will be parsed and stored into
482// config->input. Otherwise, 'data' can be NULL and no parsing will occur.
483// Note that 'config' can be NULL too, in which case a default configuration
484// is used. If 'config' is not NULL, it must outlive the WebPIDecoder object
485// as some references to its fields will be used. No internal copy of 'config'
486// is made.
487// The return WebPIDecoder object must always be deleted calling WebPIDelete().
488// Returns NULL in case of error (and config->status will then reflect
489// the error condition, if available).
490WEBP_EXTERN WebPIDecoder* WebPIDecode(const uint8_t* data, size_t data_size,
491 WebPDecoderConfig* config);
492
493// Non-incremental version. This version decodes the full data at once, taking
494// 'config' into account. Returns decoding status (which should be VP8_STATUS_OK
495// if the decoding was successful). Note that 'config' cannot be NULL.
496WEBP_EXTERN VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
497 WebPDecoderConfig* config);
498
499#ifdef __cplusplus
500} // extern "C"
501#endif
502
503#endif // WEBP_WEBP_DECODE_H_
504

source code of qtimageformats/src/3rdparty/libwebp/src/webp/decode.h