dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-13 06:24:27 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

Speed up lossless encoder.

Browse Source 
Speedup lossless encoder by 20-25% by optimizing:
- GetBestColorTransformForTile: Use techniques like binary search and
  local minima search to reduce the search space.
- VP8LFastSLog2Slow & VP8LFastLog2Slow: Adding the correction factor for
  log(1 + x) and increase the threshold for calling the approximate
  version of log_2 (compared to costly call to log()).

Change-Id: Ia2444c914521ac298492aafa458e617028fc2f9d
This commit is contained in:
Vikas Arora
2014-02-21 11:41:38 -08:00
parent 77a8f91981
commit c16cd99aba
3 changed files with 205 additions and 99 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
src/enc/vp8l.c
View File

@ -695,9 +695,8 @@ 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 < 25) ? 32 : (quality > 50) ? 8 : 16;
VP8LColorSpaceTransform(width, height, ccolor_transform_bits, step,
VP8LColorSpaceTransform(width, height, ccolor_transform_bits, quality,
enc->argb_, enc->transform_data_);
VP8LWriteBits(bw, 1, TRANSFORM_PRESENT);
VP8LWriteBits(bw, 2, CROSS_COLOR_TRANSFORM);