// 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)
#include <stdlib.h>
#include "./vp8i.h"
#include "./vp8li.h"
#include "./webpi.h"
#include "../utils/utils.h"
#include "../webp/mux_types.h" // ALPHA_FLAG
//------------------------------------------------------------------------------
// RIFF layout is:
// Offset tag
// 0...3 "RIFF" 4-byte tag
// 4...7 size of image data (including metadata) starting at offset 8
// 8...11 "WEBP" our form-type signature
// The RIFF container (12 bytes) is followed by appropriate chunks:
// 12..15 "VP8 ": 4-bytes tags, signaling the use of VP8 video format
// 16..19 size of the raw VP8 image data, starting at offset 20
// 20.... the VP8 bytes
// Or,
// 12..15 "VP8L": 4-bytes tags, signaling the use of VP8L lossless format
// 16..19 size of the raw VP8L image data, starting at offset 20
// 20.... the VP8L bytes
// Or,
// 12..15 "VP8X": 4-bytes tags, describing the extended-VP8 chunk.
// 16..19 size of the VP8X chunk starting at offset 20.
// 20..23 VP8X flags bit-map corresponding to the chunk-types present.
// 24..26 Width of the Canvas Image.
// 27..29 Height of the Canvas Image.
// There can be extra chunks after the "VP8X" chunk (ICCP, FRGM, ANMF, VP8,
// VP8L, XMP, EXIF ...)
// All sizes are in little-endian order.
// Note: chunk data size must be padded to multiple of 2 when written.
// Validates the RIFF container (if detected) and skips over it.
// If a RIFF container is detected, returns:
// VP8_STATUS_BITSTREAM_ERROR for invalid header,
// VP8_STATUS_NOT_ENOUGH_DATA for truncated data if have_all_data is true,
// and VP8_STATUS_OK otherwise.
// In case there are not enough bytes (partial RIFF container), return 0 for
// *riff_size. Else return the RIFF size extracted from the header.
static VP8StatusCode ParseRIFF(const uint8_t** const data,
size_t* const data_size, int have_all_data,
size_t* const riff_size) {
assert(data != NULL);
assert(data_size != NULL);
assert(riff_size != NULL);
*riff_size = 0; // Default: no RIFF present.
if (*data_size >= RIFF_HEADER_SIZE && !memcmp(*data, "RIFF", TAG_SIZE)) {
if (memcmp(*data + 8, "WEBP", TAG_SIZE)) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong image file signature.
} else {
const uint32_t size = GetLE32(*data + TAG_SIZE);
// Check that we have at least one chunk (i.e "WEBP" + "VP8?nnnn").
if (size < TAG_SIZE + CHUNK_HEADER_SIZE) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (size > MAX_CHUNK_PAYLOAD) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (have_all_data && (size > *data_size - CHUNK_HEADER_SIZE)) {
return VP8_STATUS_NOT_ENOUGH_DATA; // Truncated bitstream.
}
// We have a RIFF container. Skip it.
*riff_size = size;
*data += RIFF_HEADER_SIZE;
*data_size -= RIFF_HEADER_SIZE;
}
}
return VP8_STATUS_OK;
}
// Validates the VP8X header and skips over it.
// Returns VP8_STATUS_BITSTREAM_ERROR for invalid VP8X header,
// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
// VP8_STATUS_OK otherwise.
// If a VP8X chunk is found, found_vp8x is set to true and *width_ptr,
// *height_ptr and *flags_ptr are set to the corresponding values extracted
// from the VP8X chunk.
static VP8StatusCode ParseVP8X(const uint8_t** const data,
size_t* const data_size,
int* const found_vp8x,
int* const width_ptr, int* const height_ptr,
uint32_t* const flags_ptr) {
const uint32_t vp8x_size = CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE;
assert(data != NULL);
assert(data_size != NULL);
assert(found_vp8x != NULL);
*found_vp8x = 0;
if (*data_size < CHUNK_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
}
if (!memcmp(*data, "VP8X", TAG_SIZE)) {
int width, height;
uint32_t flags;
const uint32_t chunk_size = GetLE32(*data + TAG_SIZE);
if (chunk_size != VP8X_CHUNK_SIZE) {
return VP8_STATUS_BITSTREAM_ERROR; // Wrong chunk size.
}
// Verify if enough data is available to validate the VP8X chunk.
if (*data_size < vp8x_size) {
return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
}
flags = GetLE32(*data + 8);
width = 1 + GetLE24(*data + 12);
height = 1 + GetLE24(*data + 15);
if (width * (uint64_t)height >= MAX_IMAGE_AREA) {
return VP8_STATUS_BITSTREAM_ERROR; // image is too large
}
if (flags_ptr != NULL) *flags_ptr = flags;
if (width_ptr != NULL) *width_ptr = width;
if (height_ptr != NULL) *height_ptr = height;
// Skip over VP8X header bytes.
*data += vp8x_size;
*data_size -= vp8x_size;
*found_vp8x = 1;
}
return VP8_STATUS_OK;
}
// Skips to the next VP8/VP8L chunk header in the data given the size of the
// RIFF chunk 'riff_size'.
// Returns VP8_STATUS_BITSTREAM_ERROR if any invalid chunk size is encountered,
// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
// VP8_STATUS_OK otherwise.
// If an alpha chunk is found, *alpha_data and *alpha_size are set
// appropriately.
static VP8StatusCode ParseOptionalChunks(const uint8_t** const data,
size_t* const data_size,
size_t const riff_size,
const uint8_t** const alpha_data,
size_t* const alpha_size) {
const uint8_t* buf;
size_t buf_size;
uint32_t total_size = TAG_SIZE + // "WEBP".
CHUNK_HEADER_SIZE + // "VP8Xnnnn".
VP8X_CHUNK_SIZE; // data.
assert(data != NULL);
assert(data_size != NULL);
buf = *data;
buf_size = *data_size;
assert(alpha_data != NULL);
assert(alpha_size != NULL);
*alpha_data = NULL;
*alpha_size = 0;
while (1) {
uint32_t chunk_size;
uint32_t disk_chunk_size; // chunk_size with padding
*data = buf;
*data_size = buf_size;
if (buf_size < CHUNK_HEADER_SIZE) { // Insufficient data.
return VP8_STATUS_NOT_ENOUGH_DATA;
}
chunk_size = GetLE32(buf + TAG_SIZE);
if (chunk_size > MAX_CHUNK_PAYLOAD) {
return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size.
}
// For odd-sized chunk-payload, there's one byte padding at the end.
disk_chunk_size = (CHUNK_HEADER_SIZE + chunk_size + 1) & ~1;
total_size += disk_chunk_size;
// Check that total bytes skipped so far does not exceed riff_size.
if (riff_size > 0 && (total_size > riff_size)) {
return VP8_STATUS_BITSTREAM_ERROR; // Not a valid chunk size.
}
// Start of a (possibly incomplete) VP8/VP8L chunk implies that we have
// parsed all the optional chunks.
// Note: This check must occur before the check 'buf_size < disk_chunk_size'
// below to allow incomplete VP8/VP8L chunks.
if (!memcmp(buf, "VP8 ", TAG_SIZE) ||
!memcmp(buf, "VP8L", TAG_SIZE)) {
return VP8_STATUS_OK;
}
if (buf_size < disk_chunk_size) { // Insufficient data.
return VP8_STATUS_NOT_ENOUGH_DATA;
}
if (!memcmp(buf, "ALPH", TAG_SIZE)) { // A valid ALPH header.
*alpha_data = buf + CHUNK_HEADER_SIZE;
*alpha_size = chunk_size;
}
// We have a full and valid chunk; skip it.
buf += disk_chunk_size;
buf_size -= disk_chunk_size;
}
}
// Validates the VP8/VP8L Header ("VP8 nnnn" or "VP8L nnnn") and skips over it.
// Returns VP8_STATUS_BITSTREAM_ERROR for invalid (chunk larger than
// riff_size) VP8/VP8L header,
// VP8_STATUS_NOT_ENOUGH_DATA in case of insufficient data, and
// VP8_STATUS_OK otherwise.
// If a VP8/VP8L chunk is found, *chunk_size is set to the total number of bytes
// extracted from the VP8/VP8L chunk header.
// The flag '*is_lossless' is set to 1 in case of VP8L chunk / raw VP8L data.
static VP8StatusCode ParseVP8Header(const uint8_t** const data_ptr,
size_t* const data_size, int have_all_data,
size_t riff_size, size_t* const chunk_size,
int* const is_lossless) {
const uint8_t* const data = *data_ptr;
const int is_vp8 = !memcmp(data, "VP8 ", TAG_SIZE);
const int is_vp8l = !memcmp(data, "VP8L", TAG_SIZE);
const uint32_t minimal_size =
TAG_SIZE + CHUNK_HEADER_SIZE; // "WEBP" + "VP8 nnnn" OR
// "WEBP" + "VP8Lnnnn"
assert(data != NULL);
assert(data_size != NULL);
assert(chunk_size != NULL);
assert(is_lossless != NULL);
if (*data_size < CHUNK_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA; // Insufficient data.
}
if (is_vp8 || is_vp8l) {
// Bitstream contains VP8/VP8L header.
const uint32_t size = GetLE32(data + TAG_SIZE);
if ((riff_size >= minimal_size) && (size > riff_size - minimal_size)) {
return VP8_STATUS_BITSTREAM_ERROR; // Inconsistent size information.
}
if (have_all_data && (size > *data_size - CHUNK_HEADER_SIZE)) {
return VP8_STATUS_NOT_ENOUGH_DATA; // Truncated bitstream.
}
// Skip over CHUNK_HEADER_SIZE bytes from VP8/VP8L Header.
*chunk_size = size;
*data_ptr += CHUNK_HEADER_SIZE;
*data_size -= CHUNK_HEADER_SIZE;
*is_lossless = is_vp8l;
} else {
// Raw VP8/VP8L bitstream (no header).
*is_lossless = VP8LCheckSignature(data, *data_size);
*chunk_size = *data_size;
}
return VP8_STATUS_OK;
}
//------------------------------------------------------------------------------
// Fetch '*width', '*height', '*has_alpha' and fill out 'headers' based on
// 'data'. All the output parameters may be NULL. If 'headers' is NULL only the
// minimal amount will be read to fetch the remaining parameters.
// If 'headers' is non-NULL this function will attempt to locate both alpha
// data (with or without a VP8X chunk) and the bitstream chunk (VP8/VP8L).
// 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 VP8StatusCode ParseHeadersInternal(const uint8_t* data,
size_t data_size,
int* const width,
int* const height,
int* const has_alpha,
int* const has_animation,
int* const format,
WebPHeaderStructure* const headers) {
int canvas_width = 0;
int canvas_height = 0;
int image_width = 0;
int image_height = 0;
int found_riff = 0;
int found_vp8x = 0;
int animation_present = 0;
int fragments_present = 0;
const int have_all_data = (headers != NULL) ? headers->have_all_data : 0;
VP8StatusCode status;
WebPHeaderStructure hdrs;
if (data == NULL || data_size < RIFF_HEADER_SIZE) {
return VP8_STATUS_NOT_ENOUGH_DATA;
}
memset(&hdrs, 0, sizeof(hdrs));
hdrs.data = data;
hdrs.data_size = data_size;
// Skip over RIFF header.
status = ParseRIFF(&data, &data_size, have_all_data, &hdrs.riff_size);
if (status != VP8_STATUS_OK) {
return status; // Wrong RIFF header / insufficient data.
}
found_riff = (hdrs.riff_size > 0);
// Skip over VP8X.
{
uint32_t flags = 0;
status = ParseVP8X(&data, &data_size, &found_vp8x,
&canvas_width, &canvas_height, &flags);
if (status != VP8_STATUS_OK) {
return status; // Wrong VP8X / insufficient data.
}
animation_present = !!(flags & ANIMATION_FLAG);
fragments_present = !!(flags & FRAGMENTS_FLAG);
if (!found_riff && found_vp8x) {
// Note: This restriction may be removed in the future, if it becomes
// necessary to send VP8X chunk to the decoder.
return VP8_STATUS_BITSTREAM_ERROR;
}
if (has_alpha != NULL) *has_alpha = !!(flags & ALPHA_FLAG);
if (has_animation != NULL) *has_animation = animation_present;
if (format != NULL) *format = 0; // default = undefined
image_width = canvas_width;
image_height = canvas_height;
if (found_vp8x && (animation_present || fragments_present) &&
headers == NULL) {
status = VP8_STATUS_OK;
goto ReturnWidthHeight; // Just return features from VP8X header.
}
}
if (data_size < TAG_SIZE) {
status = VP8_STATUS_NOT_ENOUGH_DATA;
goto ReturnWidthHeight;
}
// Skip over optional chunks if data started with "RIFF + VP8X" or "ALPH".
if ((found_riff && found_vp8x) ||
(!found_riff && !found_vp8x && !memcmp(data, "ALPH", TAG_SIZE))) {
status = ParseOptionalChunks(&data, &data_size, hdrs.riff_size,
&hdrs.alpha_data, &hdrs.alpha_data_size);
if (status != VP8_STATUS_OK) {
goto ReturnWidthHeight; // Invalid chunk size / insufficient data.
}
}
// Skip over VP8/VP8L header.
status = ParseVP8Header(&data, &data_size, have_all_data, hdrs.riff_size,
&hdrs.compressed_size, &hdrs.is_lossless);
if (status != VP8_STATUS_OK) {
goto ReturnWidthHeight; // Wrong VP8/VP8L chunk-header / insufficient data.
}
if (hdrs.compressed_size > MAX_CHUNK_PAYLOAD) {
return VP8_STATUS_BITSTREAM_ERROR;
}
if (format != NULL && !(animation_present || fragments_present)) {
*format = hdrs.is_lossless ? 2 : 1;
}
if (!hdrs.is_lossless) {
if (data_size < VP8_FRAME_HEADER_SIZE) {
status = VP8_STATUS_NOT_ENOUGH_DATA;
goto ReturnWidthHeight;
}
// Validates raw VP8 data.
if (!VP8GetInfo(data, data_size, (uint32_t)hdrs.compressed_size,
&image_width, &image_height)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
} else {
if (data_size < VP8L_FRAME_HEADER_SIZE) {
status = VP8_STATUS_NOT_ENOUGH_DATA;
goto ReturnWidthHeight;
}
// Validates raw VP8L data.
if (!VP8LGetInfo(data, data_size, &image_width, &image_height, has_alpha)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
}
// Validates image size coherency.
if (found_vp8x) {
if (canvas_width != image_width || canvas_height != image_height) {
return VP8_STATUS_BITSTREAM_ERROR;
}
}
if (headers != NULL) {
*headers = hdrs;
headers->offset = data - headers->data;
assert((uint64_t)(data - headers->data) < MAX_CHUNK_PAYLOAD);
assert(headers->offset == headers->data_size - data_size);
}
ReturnWidthHeight:
if (status == VP8_STATUS_OK ||
(status == VP8_STATUS_NOT_ENOUGH_DATA && found_vp8x && headers == NULL)) {
if (has_alpha != NULL) {
// If the data did not contain a VP8X/VP8L chunk the only definitive way
// to set this is by looking for alpha data (from an ALPH chunk).
*has_alpha |= (hdrs.alpha_data != NULL);
}
if (width != NULL) *width = image_width;
if (height != NULL) *height = image_height;
return VP8_STATUS_OK;
} else {
return status;
}
}
VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
// status is marked volatile as a workaround for b/25845393
volatile VP8StatusCode status;
int has_animation = 0;
assert(headers != NULL);
// fill out headers, ignore width/height/has_alpha.
status = ParseHeadersInternal(headers->data, headers->data_size,
NULL, NULL, NULL, &has_animation,
NULL, headers);
if (status == VP8_STATUS_OK || status == VP8_STATUS_NOT_ENOUGH_DATA) {
// TODO(jzern): full support of animation frames will require API additions.
if (has_animation) {
status = VP8_STATUS_UNSUPPORTED_FEATURE;
}
}
return status;
}
//------------------------------------------------------------------------------
// WebPDecParams
void WebPResetDecParams(WebPDecParams* const params) {
if (params != NULL) {
memset(params, 0, sizeof(*params));
}
}
//------------------------------------------------------------------------------
// "Into" decoding variants
// Main flow
static VP8StatusCode DecodeInto(const uint8_t* const data, size_t data_size,
WebPDecParams* const params) {
VP8StatusCode status;
VP8Io io;
WebPHeaderStructure headers;
headers.data = data;
headers.data_size = data_size;
headers.have_all_data = 1;
status = WebPParseHeaders(&headers); // Process Pre-VP8 chunks.
if (status != VP8_STATUS_OK) {
return status;
}
assert(params != NULL);
VP8InitIo(&io);
io.data = headers.data + headers.offset;
io.data_size = headers.data_size - headers.offset;
WebPInitCustomIo(params, &io); // Plug the I/O functions.
if (!headers.is_lossless) {
VP8Decoder* const dec = VP8New();
if (dec == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
dec->alpha_data_ = headers.alpha_data;
dec->alpha_data_size_ = headers.alpha_data_size;
// Decode bitstream header, update io->width/io->height.
if (!VP8GetHeaders(dec, &io)) {
status = dec->status_; // An error occurred. Grab error status.
} else {
// Allocate/check output buffers.
status = WebPAllocateDecBuffer(io.width, io.height, params->options,
params->output);
if (status == VP8_STATUS_OK) { // Decode
// This change must be done before calling VP8Decode()
dec->mt_method_ = VP8GetThreadMethod(params->options, &headers,
io.width, io.height);
VP8InitDithering(params->options, dec);
if (!VP8Decode(dec, &io)) {
status = dec->status_;
}
}
}
VP8Delete(dec);
} else {
VP8LDecoder* const dec = VP8LNew();
if (dec == NULL) {
return VP8_STATUS_OUT_OF_MEMORY;
}
if (!VP8LDecodeHeader(dec, &io)) {
status = dec->status_; // An error occurred. Grab error status.
} else {
// Allocate/check output buffers.
status = WebPAllocateDecBuffer(io.width, io.height, params->options,
params->output);
if (status == VP8_STATUS_OK) { // Decode
if (!VP8LDecodeImage(dec)) {
status = dec->status_;
}
}
}
VP8LDelete(dec);
}
if (status != VP8_STATUS_OK) {
WebPFreeDecBuffer(params->output);
}
if (params->options != NULL && params->options->flip) {
status = WebPFlipBuffer(params->output);
}
return status;
}
// Helpers
static uint8_t* DecodeIntoRGBABuffer(WEBP_CSP_MODE colorspace,
const uint8_t* const data,
size_t data_size,
uint8_t* const rgba,
int stride, size_t size) {
WebPDecParams params;
WebPDecBuffer buf;
if (rgba == NULL) {
return NULL;
}
WebPInitDecBuffer(&buf);
WebPResetDecParams(¶ms);
params.output = &buf;
buf.colorspace = colorspace;
buf.u.RGBA.rgba = rgba;
buf.u.RGBA.stride = stride;
buf.u.RGBA.size = size;
buf.is_external_memory = 1;
if (DecodeInto(data, data_size, ¶ms) != VP8_STATUS_OK) {
return NULL;
}
return rgba;
}
uint8_t* WebPDecodeRGBInto(const uint8_t* data, size_t data_size,
uint8_t* output, size_t size, int stride) {
return DecodeIntoRGBABuffer(MODE_RGB, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeRGBAInto(const uint8_t* data, size_t data_size,
uint8_t* output, size_t size, int stride) {
return DecodeIntoRGBABuffer(MODE_RGBA, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeARGBInto(const uint8_t* data, size_t data_size,
uint8_t* output, size_t size, int stride) {
return DecodeIntoRGBABuffer(MODE_ARGB, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeBGRInto(const uint8_t* data, size_t data_size,
uint8_t* output, size_t size, int stride) {
return DecodeIntoRGBABuffer(MODE_BGR, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeBGRAInto(const uint8_t* data, size_t data_size,
uint8_t* output, size_t size, int stride) {
return DecodeIntoRGBABuffer(MODE_BGRA, data, data_size, output, stride, size);
}
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) {
WebPDecParams params;
WebPDecBuffer output;
if (luma == NULL) return NULL;
WebPInitDecBuffer(&output);
WebPResetDecParams(¶ms);
params.output = &output;
output.colorspace = MODE_YUV;
output.u.YUVA.y = luma;
output.u.YUVA.y_stride = luma_stride;
output.u.YUVA.y_size = luma_size;
output.u.YUVA.u = u;
output.u.YUVA.u_stride = u_stride;
output.u.YUVA.u_size = u_size;
output.u.YUVA.v = v;
output.u.YUVA.v_stride = v_stride;
output.u.YUVA.v_size = v_size;
output.is_external_memory = 1;
if (DecodeInto(data, data_size, ¶ms) != VP8_STATUS_OK) {
return NULL;
}
return luma;
}
//------------------------------------------------------------------------------
static uint8_t* Decode(WEBP_CSP_MODE mode, const uint8_t* const data,
size_t data_size, int* const width, int* const height,
WebPDecBuffer* const keep_info) {
WebPDecParams params;
WebPDecBuffer output;
WebPInitDecBuffer(&output);
WebPResetDecParams(¶ms);
params.output = &output;
output.colorspace = mode;
// Retrieve (and report back) the required dimensions from bitstream.
if (!WebPGetInfo(data, data_size, &output.width, &output.height)) {
return NULL;
}
if (width != NULL) *width = output.width;
if (height != NULL) *height = output.height;
// Decode
if (DecodeInto(data, data_size, ¶ms) != VP8_STATUS_OK) {
return NULL;
}
if (keep_info != NULL) { // keep track of the side-info
WebPCopyDecBuffer(&output, keep_info);
}
// return decoded samples (don't clear 'output'!)
return WebPIsRGBMode(mode) ? output.u.RGBA.rgba : output.u.YUVA.y;
}
uint8_t* WebPDecodeRGB(const uint8_t* data, size_t data_size,
int* width, int* height) {
return Decode(MODE_RGB, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeRGBA(const uint8_t* data, size_t data_size,
int* width, int* height) {
return Decode(MODE_RGBA, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeARGB(const uint8_t* data, size_t data_size,
int* width, int* height) {
return Decode(MODE_ARGB, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeBGR(const uint8_t* data, size_t data_size,
int* width, int* height) {
return Decode(MODE_BGR, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeBGRA(const uint8_t* data, size_t data_size,
int* width, int* height) {
return Decode(MODE_BGRA, data, data_size, width, height, NULL);
}
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) {
WebPDecBuffer output; // only to preserve the side-infos
uint8_t* const out = Decode(MODE_YUV, data, data_size,
width, height, &output);
if (out != NULL) {
const WebPYUVABuffer* const buf = &output.u.YUVA;
*u = buf->u;
*v = buf->v;
*stride = buf->y_stride;
*uv_stride = buf->u_stride;
assert(buf->u_stride == buf->v_stride);
}
return out;
}
static void DefaultFeatures(WebPBitstreamFeatures* const features) {
assert(features != NULL);
memset(features, 0, sizeof(*features));
}
static VP8StatusCode GetFeatures(const uint8_t* const data, size_t data_size,
WebPBitstreamFeatures* const features) {
if (features == NULL || data == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
DefaultFeatures(features);
// Only parse enough of the data to retrieve the features.
return ParseHeadersInternal(data, data_size,
&features->width, &features->height,
&features->has_alpha, &features->has_animation,
&features->format, NULL);
}
//------------------------------------------------------------------------------
// WebPGetInfo()
int WebPGetInfo(const uint8_t* data, size_t data_size,
int* width, int* height) {
WebPBitstreamFeatures features;
if (GetFeatures(data, data_size, &features) != VP8_STATUS_OK) {
return 0;
}
if (width != NULL) {
*width = features.width;
}
if (height != NULL) {
*height = features.height;
}
return 1;
}
//------------------------------------------------------------------------------
// Advance decoding API
int WebPInitDecoderConfigInternal(WebPDecoderConfig* config,
int version) {
if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) {
return 0; // version mismatch
}
if (config == NULL) {
return 0;
}
memset(config, 0, sizeof(*config));
DefaultFeatures(&config->input);
WebPInitDecBuffer(&config->output);
return 1;
}
VP8StatusCode WebPGetFeaturesInternal(const uint8_t* data, size_t data_size,
WebPBitstreamFeatures* features,
int version) {
if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_DECODER_ABI_VERSION)) {
return VP8_STATUS_INVALID_PARAM; // version mismatch
}
if (features == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
return GetFeatures(data, data_size, features);
}
VP8StatusCode WebPDecode(const uint8_t* data, size_t data_size,
WebPDecoderConfig* config) {
WebPDecParams params;
VP8StatusCode status;
if (config == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
status = GetFeatures(data, data_size, &config->input);
if (status != VP8_STATUS_OK) {
if (status == VP8_STATUS_NOT_ENOUGH_DATA) {
return VP8_STATUS_BITSTREAM_ERROR; // Not-enough-data treated as error.
}
return status;
}
WebPResetDecParams(¶ms);
params.output = &config->output;
params.options = &config->options;
status = DecodeInto(data, data_size, ¶ms);
return status;
}
//------------------------------------------------------------------------------
// Cropping and rescaling.
int WebPIoInitFromOptions(const WebPDecoderOptions* const options,
VP8Io* const io, WEBP_CSP_MODE src_colorspace) {
const int W = io->width;
const int H = io->height;
int x = 0, y = 0, w = W, h = H;
// Cropping
io->use_cropping = (options != NULL) && (options->use_cropping > 0);
if (io->use_cropping) {
w = options->crop_width;
h = options->crop_height;
x = options->crop_left;
y = options->crop_top;
if (!WebPIsRGBMode(src_colorspace)) { // only snap for YUV420
x &= ~1;
y &= ~1;
}
if (x < 0 || y < 0 || w <= 0 || h <= 0 || x + w > W || y + h > H) {
return 0; // out of frame boundary error
}
}
io->crop_left = x;
io->crop_top = y;
io->crop_right = x + w;
io->crop_bottom = y + h;
io->mb_w = w;
io->mb_h = h;
// Scaling
io->use_scaling = (options != NULL) && (options->use_scaling > 0);
if (io->use_scaling) {
int scaled_width = options->scaled_width;
int scaled_height = options->scaled_height;
if (!WebPRescalerGetScaledDimensions(w, h, &scaled_width, &scaled_height)) {
return 0;
}
io->scaled_width = scaled_width;
io->scaled_height = scaled_height;
}
// Filter
io->bypass_filtering = options && options->bypass_filtering;
// Fancy upsampler
#ifdef FANCY_UPSAMPLING
io->fancy_upsampling = (options == NULL) || (!options->no_fancy_upsampling);
#endif
if (io->use_scaling) {
// disable filter (only for large downscaling ratio).
io->bypass_filtering = (io->scaled_width < W * 3 / 4) &&
(io->scaled_height < H * 3 / 4);
io->fancy_upsampling = 0;
}
return 1;
}
//------------------------------------------------------------------------------