// Copyright 2010 Google Inc.
//
// This code is licensed under the same terms as WebM:
// Software License Agreement: http://www.webmproject.org/license/software/
// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
// -----------------------------------------------------------------------------
//
// Main decoding functions for WEBP images.
//
// Author: Skal (pascal.massimino@gmail.com)
#include <stdlib.h>
#include "vp8i.h"
#include "webpi.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
//-----------------------------------------------------------------------------
// RIFF layout is:
// 0ffset 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
// 12..15 "VP8 ": 4-bytes tags, describing the raw video format used
// 16..19 size of the raw VP8 image data, starting at offset 20
// 20.... the VP8 bytes
// There can be extra chunks after the "VP8 " chunk (ICMT, ICOP, ...)
// All 32-bits sizes are in little-endian order.
// Note: chunk data must be padded to multiple of 2 in size
static inline uint32_t get_le32(const uint8_t* const data) {
return data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
}
// If a RIFF container is detected, validate it and skip over it.
uint32_t WebPCheckRIFFHeader(const uint8_t** data_ptr,
uint32_t* data_size_ptr) {
uint32_t chunk_size = 0xffffffffu;
if (*data_size_ptr >= 10 + 20 && !memcmp(*data_ptr, "RIFF", 4)) {
if (memcmp(*data_ptr + 8, "WEBP", 4)) {
return 0; // wrong image file signature
} else {
const uint32_t riff_size = get_le32(*data_ptr + 4);
if (riff_size < 12) {
return 0; // we should have at least one chunk
}
if (memcmp(*data_ptr + 12, "VP8 ", 4)) {
return 0; // invalid compression format
}
chunk_size = get_le32(*data_ptr + 16);
if (chunk_size > riff_size - 12) {
return 0; // inconsistent size information.
}
// We have a RIFF container. Skip it.
*data_ptr += 20;
*data_size_ptr -= 20;
// Note: we don't report error for odd-sized chunks.
}
return chunk_size;
}
return *data_size_ptr;
}
//-----------------------------------------------------------------------------
// WebPDecParams
void WebPResetDecParams(WebPDecParams* const params) {
if (params) {
memset(params, 0, sizeof(*params));
}
}
//-----------------------------------------------------------------------------
// "Into" decoding variants
// Main flow
static VP8StatusCode DecodeInto(const uint8_t* data, uint32_t data_size,
WebPDecParams* const params) {
VP8Decoder* dec = VP8New();
VP8StatusCode status = VP8_STATUS_OK;
VP8Io io;
assert(params);
if (dec == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
VP8InitIo(&io);
io.data = data;
io.data_size = data_size;
WebPInitCustomIo(params, &io); // Plug the I/O functions.
// Decode bitstream header, update io->width/io->height.
if (!VP8GetHeaders(dec, &io)) {
status = VP8_STATUS_BITSTREAM_ERROR;
} else {
// Allocate/check output buffers.
status = WebPAllocateDecBuffer(io.width, io.height, params->options,
params->output);
if (status == VP8_STATUS_OK) {
// Decode
if (!VP8Decode(dec, &io)) {
status = dec->status_;
}
}
}
VP8Delete(dec);
if (status != VP8_STATUS_OK) {
WebPFreeDecBuffer(params->output);
}
return status;
}
// Helpers
static uint8_t* DecodeIntoRGBABuffer(WEBP_CSP_MODE colorspace,
const uint8_t* data, uint32_t data_size,
uint8_t* rgba, int stride, int 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, uint32_t data_size,
uint8_t* output, int size, int stride) {
return DecodeIntoRGBABuffer(MODE_RGB, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeRGBAInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int size, int stride) {
return DecodeIntoRGBABuffer(MODE_RGBA, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeARGBInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int size, int stride) {
return DecodeIntoRGBABuffer(MODE_ARGB, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeBGRInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int size, int stride) {
return DecodeIntoRGBABuffer(MODE_BGR, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeBGRAInto(const uint8_t* data, uint32_t data_size,
uint8_t* output, int size, int stride) {
return DecodeIntoRGBABuffer(MODE_BGRA, data, data_size, output, stride, size);
}
uint8_t* WebPDecodeYUVInto(const uint8_t* data, uint32_t data_size,
uint8_t* luma, int luma_size, int luma_stride,
uint8_t* u, int u_size, int u_stride,
uint8_t* v, int 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* data,
uint32_t data_size, int* width, int* height,
WebPDecBuffer* 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) *width = output.width;
if (height) *height = output.height;
// Decode
if (DecodeInto(data, data_size, ¶ms) != VP8_STATUS_OK) {
return NULL;
}
if (keep_info) { // keep track of the side-info
WebPCopyDecBuffer(&output, keep_info);
}
// return decoded samples (don't clear 'output'!)
return (mode >= MODE_YUV) ? output.u.YUVA.y : output.u.RGBA.rgba;
}
uint8_t* WebPDecodeRGB(const uint8_t* data, uint32_t data_size,
int* width, int* height) {
return Decode(MODE_RGB, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeRGBA(const uint8_t* data, uint32_t data_size,
int* width, int* height) {
return Decode(MODE_RGBA, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeARGB(const uint8_t* data, uint32_t data_size,
int* width, int* height) {
return Decode(MODE_ARGB, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeBGR(const uint8_t* data, uint32_t data_size,
int* width, int* height) {
return Decode(MODE_BGR, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeBGRA(const uint8_t* data, uint32_t data_size,
int* width, int* height) {
return Decode(MODE_BGRA, data, data_size, width, height, NULL);
}
uint8_t* WebPDecodeYUV(const uint8_t* data, uint32_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) {
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;
}
//-----------------------------------------------------------------------------
// WebPGetInfo()
int WebPGetInfo(const uint8_t* data, uint32_t data_size,
int* width, int* height) {
const uint32_t chunk_size = WebPCheckRIFFHeader(&data, &data_size);
if (!chunk_size) {
return 0; // unsupported RIFF header
}
// Validate raw video data
return VP8GetInfo(data, data_size, chunk_size, width, height, NULL);
}
static void DefaultFeatures(WebPBitstreamFeatures* const features) {
assert(features);
memset(features, 0, sizeof(*features));
features->bitstream_version = 0;
}
static VP8StatusCode GetFeatures(const uint8_t** data, uint32_t* data_size,
WebPBitstreamFeatures* const features) {
uint32_t chunk_size;
if (features == NULL) {
return VP8_STATUS_INVALID_PARAM;
}
DefaultFeatures(features);
if (data == NULL || *data == NULL || data_size == 0) {
return VP8_STATUS_INVALID_PARAM;
}
chunk_size = WebPCheckRIFFHeader(data, data_size);
if (chunk_size == 0) {
return VP8_STATUS_BITSTREAM_ERROR; // unsupported RIFF header
}
if (!VP8GetInfo(*data, *data_size, chunk_size,
&features->width, &features->height, &features->has_alpha)) {
return VP8_STATUS_BITSTREAM_ERROR;
}
return VP8_STATUS_OK;
}
//-----------------------------------------------------------------------------
// Advance decoding API
int WebPInitDecoderConfigInternal(WebPDecoderConfig* const config,
int version) {
if (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, uint32_t data_size,
WebPBitstreamFeatures* const features,
int version) {
if (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, uint32_t data_size,
WebPDecoderConfig* const config) {
WebPDecParams params;
VP8StatusCode status;
if (!config) {
return VP8_STATUS_INVALID_PARAM;
}
status = GetFeatures(&data, &data_size, &config->input);
if (status != VP8_STATUS_OK) {
return status;
}
WebPResetDecParams(¶ms);
params.output = &config->output;
params.options = &config->options;
status = DecodeInto(data, data_size, ¶ms);
return status;
}
#if defined(__cplusplus) || defined(c_plusplus)
} // extern "C"
#endif