dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-01-28 23:52:56 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity

Tuned cross_color parameter (step) for lower qual

Browse Source 
Tuned the cross_color transform parameter (step) for lower quality
levels. This change gives speedup of 20% at lower qualities (25) and 10% at
moderate quality level (50) with a loss of 0.25% in compression density.
Also removed TODO for cross_color transform. Observed good correlation of
this with the predict transform.

Change-Id: I8a1044e9f24e6a5f84295c030fd444d0eec7d154
This commit is contained in:
Vikas Arora 2013-06-11 12:12:47 -07:00
parent 90e2ec5a1b
commit bf867bf296
1 changed files with 1 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
src/enc/vp8l.c
View File

@ -168,9 +168,6 @@ static int VP8LEncAnalyze(VP8LEncoder* const enc, WebPImageHint image_hint) {
}
if (pred_entropy < 0.95 * non_pred_entropy) {
enc->use_predict_ = 1;
// TODO(vikasa): Observed some correlation of cross_color transform with
// predict. Need to investigate this further and add separate heuristic
// for setting use_cross_color flag.
enc->use_cross_color_ = 1;
}
}
@ -702,7 +699,7 @@ static int ApplyCrossColorFilter(const VP8LEncoder* const enc,
const int ccolor_transform_bits = enc->transform_bits_;
const int transform_width = VP8LSubSampleSize(width, ccolor_transform_bits);
const int transform_height = VP8LSubSampleSize(height, ccolor_transform_bits);
const int step = (quality == 0) ? 32 : 8;
const int step = (quality < 25) ? 32 : (quality > 50) ? 8 : 16;
VP8LColorSpaceTransform(width, height, ccolor_transform_bits, step,
enc->argb_, enc->transform_data_);