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WebPAnimEncoder: Detect when canvas is modified, restore only when needed.

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Change-Id: I6b45283e13c08c7d11c96500a65c75ce3637b06d
This commit is contained in:
Urvang Joshi 2016-05-23 11:17:23 -07:00
parent 0209d7e6d6
commit 08333b8551
1 changed files with 20 additions and 13 deletions
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21
src/mux/anim_encode.c
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@ -703,21 +703,25 @@ static int GetColorCount(const WebPPicture* const pic) {
// For pixels in 'rect', replace those pixels in 'dst' that are same as 'src' by
// transparent pixels.
static void IncreaseTransparency(const WebPPicture* const src,
// Returns true if at least one pixel gets modified.
static int IncreaseTransparency(const WebPPicture* const src,
const FrameRect* const rect,
WebPPicture* const dst) {
int i, j;
int modified = 0;
assert(src != NULL && dst != NULL && rect != NULL);
assert(src->width == dst->width && src->height == dst->height);
for (j = rect->y_offset_; j < rect->y_offset_ + rect->height_; ++j) {
const uint32_t* const psrc = src->argb + j * src->argb_stride;
uint32_t* const pdst = dst->argb + j * dst->argb_stride;
for (i = rect->x_offset_; i < rect->x_offset_ + rect->width_; ++i) {
if (psrc[i] == pdst[i]) {
if (psrc[i] == pdst[i] && pdst[i] != TRANSPARENT_COLOR) {
pdst[i] = TRANSPARENT_COLOR;
modified = 1;
}
}
}
return modified;
}
#undef TRANSPARENT_COLOR
@ -725,12 +729,13 @@ static void IncreaseTransparency(const WebPPicture* const src,
// Replace similar blocks of pixels by a 'see-through' transparent block
// with uniform average color.
// Assumes lossy compression is being used.
static void FlattenSimilarBlocks(const WebPPicture* const src,
// Returns true if at least one pixel gets modified.
static int FlattenSimilarBlocks(const WebPPicture* const src,
const FrameRect* const rect,
WebPPicture* const dst,
float quality) {
WebPPicture* const dst, float quality) {
const int max_allowed_diff_lossy = QualityToMaxDiff(quality);
int i, j;
int modified = 0;
const int block_size = 8;
const int y_start = (rect->y_offset_ + block_size) & ~(block_size - 1);
const int y_end = (rect->y_offset_ + rect->height_) & ~(block_size - 1);
@ -773,9 +778,11 @@ static void FlattenSimilarBlocks(const WebPPicture* const src,
pdst[x + y * dst->argb_stride] = color;
}
}
modified = 1;
}
}
}
return modified;
}
static int EncodeFrame(const WebPConfig* const config, WebPPicture* const pic,
@ -900,8 +907,8 @@ static WebPEncodingError GenerateCandidates(
if (candidate_ll->evaluate_) {
CopyCurrentCanvas(enc);
if (use_blending_ll) {
enc->curr_canvas_copy_modified_ =
IncreaseTransparency(prev_canvas, &params->rect_ll_, curr_canvas);
enc->curr_canvas_copy_modified_ = 1;
}
error_code = EncodeCandidate(&params->sub_frame_ll_, &params->rect_ll_,
config_ll, use_blending_ll, candidate_ll);
@ -910,9 +917,9 @@ static WebPEncodingError GenerateCandidates(
if (candidate_lossy->evaluate_) {
CopyCurrentCanvas(enc);
if (use_blending_lossy) {
enc->curr_canvas_copy_modified_ =
FlattenSimilarBlocks(prev_canvas, &params->rect_lossy_, curr_canvas,
config_lossy->quality);
enc->curr_canvas_copy_modified_ = 1;
}
error_code =
EncodeCandidate(&params->sub_frame_lossy_, &params->rect_lossy_,