dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-14 21:09:55 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

use DC error diffusion for U/V at low-quality

Browse Source 
This fixes some color smearing due to heavy quantization.
This is only enabled for q <= 30 (cf ERROR_DIFFUSION_QUALITY)

Change-Id: I07e83a4d38461357a32c9e214f7eadc6db73baa9
This commit is contained in:
Pascal Massimino
2017-12-11 05:07:13 -08:00
parent 1c59020b93
commit 96bf07c560
5 changed files with 106 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
src/enc/webp_enc.c
View File

@ -159,12 +159,15 @@ static VP8Encoder* InitVP8Encoder(const WebPConfig* const config,
+ WEBP_ALIGN_CST; // align all
const size_t lf_stats_size =
config->autofilter ? sizeof(*enc->lf_stats_) + WEBP_ALIGN_CST : 0;
const size_t top_derr_size = (config->quality <= ERROR_DIFFUSION_QUALITY) ?
mb_w * sizeof(*enc->top_derr_) : 0;
uint8_t* mem;
const uint64_t size = (uint64_t)sizeof(*enc) // main struct
+ WEBP_ALIGN_CST // cache alignment
+ info_size // modes info
+ preds_size // prediction modes
+ samples_size // top/left samples
+ top_derr_size // top diffusion error
+ nz_size // coeff context bits
+ lf_stats_size; // autofilter stats
@ -175,11 +178,12 @@ static VP8Encoder* InitVP8Encoder(const WebPConfig* const config,
" info: %ld\n"
" preds: %ld\n"
" top samples: %ld\n"
" top diffusion: %ld\n"
" non-zero: %ld\n"
" lf-stats: %ld\n"
" total: %ld\n",
sizeof(*enc) + WEBP_ALIGN_CST, info_size,
preds_size, samples_size, nz_size, lf_stats_size, size);
preds_size, samples_size, top_derr_size, nz_size, lf_stats_size, size);
printf("Transient object sizes:\n"
" VP8EncIterator: %ld\n"
" VP8ModeScore: %ld\n"
@ -219,6 +223,8 @@ static VP8Encoder* InitVP8Encoder(const WebPConfig* const config,
enc->y_top_ = mem;
enc->uv_top_ = enc->y_top_ + top_stride;
mem += 2 * top_stride;
enc->top_derr_ = top_derr_size ? (DError*)mem : NULL;
mem += top_derr_size;
assert(mem <= (uint8_t*)enc + size);
enc->config_ = config;