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WebPDemuxGetI behavior change:

Browse Source 
It now returns ALPHA_FLAG for lossless images with alpha, that don't
have a VP8X chunk.

This is consistent with similar methods WebPMuxGetFeatures() and
WebPGetFeatures().

Change-Id: Ia3a4ca8f3e0f102f478bd33e0727ca5be98593df
This commit is contained in:
Urvang Joshi 2013-02-27 11:49:26 -08:00
parent 633c004db1
commit df02e4ce93
1 changed files with 24 additions and 12 deletions
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36
src/demux/demux.c
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@ -13,7 +13,7 @@
#include <string.h>
#include "../utils/utils.h"
#include "../webp/decode.h" // WebPGetInfo
#include "../webp/decode.h" // WebPGetFeatures
#include "../webp/demux.h"
#include "../webp/format_constants.h"
@ -192,13 +192,18 @@ static int AddFrame(WebPDemuxer* const dmux, Frame* const frame) {
}
// Store image bearing chunks to 'frame'.
// If 'has_vp8l_alpha' is not NULL, it will be set to true if the frame is a
// lossless image with alpha.
static ParseStatus StoreFrame(int frame_num, uint32_t min_size,
MemBuffer* const mem, Frame* const frame) {
MemBuffer* const mem, Frame* const frame,
int* const has_vp8l_alpha) {
int alpha_chunks = 0;
int image_chunks = 0;
int done = (MemDataSize(mem) < min_size);
ParseStatus status = PARSE_OK;
if (has_vp8l_alpha != NULL) *has_vp8l_alpha = 0; // Default.
if (done) return PARSE_NEED_MORE_DATA;
do {
@ -229,20 +234,22 @@ static ParseStatus StoreFrame(int frame_num, uint32_t min_size,
case MKFOURCC('V', 'P', '8', ' '):
case MKFOURCC('V', 'P', '8', 'L'):
if (image_chunks == 0) {
int width = 0, height = 0;
WebPBitstreamFeatures features;
ChunkData* const image = frame->img_components_;
++image_chunks;
frame->img_components_[0].offset_ = chunk_start_offset;
frame->img_components_[0].size_ = chunk_size;
image->offset_ = chunk_start_offset;
image->size_ = chunk_size;
// Extract the width and height from the bitstream, tolerating
// failures when the data is incomplete.
if (!WebPGetInfo(mem->buf_ + frame->img_components_[0].offset_,
frame->img_components_[0].size_, &width, &height) &&
if ((WebPGetFeatures(mem->buf_ + image->offset_, image->size_,
&features) != VP8_STATUS_OK) &&
status != PARSE_NEED_MORE_DATA) {
return PARSE_ERROR;
}
frame->width_ = width;
frame->height_ = height;
frame->width_ = features.width;
frame->height_ = features.height;
if (has_vp8l_alpha != NULL) *has_vp8l_alpha = features.has_alpha;
frame->frame_num_ = frame_num;
frame->complete_ = (status == PARSE_OK);
Skip(mem, payload_available);
@ -308,7 +315,8 @@ static ParseStatus ParseFrame(
// Store a frame only if the animation flag is set and all data for this frame
// is available.
status = StoreFrame(dmux->num_frames_ + 1, anmf_payload_size, mem, frame);
status = StoreFrame(dmux->num_frames_ + 1, anmf_payload_size, mem, frame,
NULL);
if (status != PARSE_ERROR && has_frames && frame->frame_num_ > 0) {
added_frame = AddFrame(dmux, frame);
if (added_frame) {
@ -341,7 +349,7 @@ static ParseStatus ParseFragment(WebPDemuxer* const dmux,
// Store a fragment only if the fragments flag is set and all data for this
// fragment is available.
status = StoreFrame(dmux->num_frames_, frgm_payload_size, mem, frame);
status = StoreFrame(dmux->num_frames_, frgm_payload_size, mem, frame, NULL);
if (status != PARSE_ERROR && has_fragments && frame->frame_num_ > 0) {
// Note num_frames_ is incremented only when all fragments have been
// consumed.
@ -401,6 +409,7 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
MemBuffer* const mem = &dmux->mem_;
Frame* frame;
ParseStatus status;
int has_vp8l_alpha = 0; // Frame contains a lossless image with alpha.
if (dmux->frames_ != NULL) return PARSE_ERROR;
if (SizeIsInvalid(mem, min_size)) return PARSE_ERROR;
@ -411,7 +420,8 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
// For the single image case, we allow parsing of a partial frame. But we need
// at least CHUNK_HEADER_SIZE for parsing.
status = StoreFrame(1, CHUNK_HEADER_SIZE, &dmux->mem_, frame);
status = StoreFrame(1, CHUNK_HEADER_SIZE, &dmux->mem_, frame,
&has_vp8l_alpha);
if (status != PARSE_ERROR) {
const int has_alpha = !!(dmux->feature_flags_ & ALPHA_FLAG);
// Clear any alpha when the alpha flag is missing.
@ -421,10 +431,12 @@ static ParseStatus ParseSingleImage(WebPDemuxer* const dmux) {
}
// Use the frame width/height as the canvas values for non-vp8x files.
// Also, set ALPHA_FLAG if this is a lossless image with alpha.
if (!dmux->is_ext_format_ && frame->width_ > 0 && frame->height_ > 0) {
dmux->state_ = WEBP_DEMUX_PARSED_HEADER;
dmux->canvas_width_ = frame->width_;
dmux->canvas_height_ = frame->height_;
dmux->feature_flags_ |= has_vp8l_alpha ? ALPHA_FLAG : 0;
}
AddFrame(dmux, frame);
dmux->num_frames_ = 1;