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Merge changes I25711dd5,I43188fab

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* changes:
  Fix assertions in WebPRescalerExportRow()
  Add descriptions of default configuration in help info.
This commit is contained in:
Pascal Massimino 2016-08-16 22:13:23 +00:00 committed by Gerrit Code Review
commit 9d4f209f80
5 changed files with 42 additions and 30 deletions
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23
README
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@ -220,8 +220,9 @@ assumed to be a PNG, JPEG, TIFF or WebP file.
Options:
-h / -help ............. short help
-H / -longhelp ......... long help
-q <float> ............. quality factor (0:small..100:big)
-alpha_q <int> ......... transparency-compression quality (0..100)
-q <float> ............. quality factor (0:small..100:big), default=75
-alpha_q <int> ......... transparency-compression quality (0..100),
default=100
-preset <string> ....... preset setting, one of:
default, photo, picture,
drawing, icon, text
@ -229,15 +230,15 @@ Options:
-z <int> ............... activates lossless preset with given
level in [0:fast, ..., 9:slowest]
-m <int> ............... compression method (0=fast, 6=slowest)
-segments <int> ........ number of segments to use (1..4)
-m <int> ............... compression method (0=fast, 6=slowest), default=4
-segments <int> ........ number of segments to use (1..4), default=4
-size <int> ............ target size (in bytes)
-psnr <float> .......... target PSNR (in dB. typically: 42)
-s <int> <int> ......... input size (width x height) for YUV
-sns <int> ............. spatial noise shaping (0:off, 100:max)
-f <int> ............... filter strength (0=off..100)
-sharpness <int> ....... filter sharpness (0:most .. 7:least sharp)
-sns <int> ............. spatial noise shaping (0:off, 100:max), default=50
-f <int> ............... filter strength (0=off..100), default=60
-sharpness <int> ....... filter sharpness (0:most .. 7:least sharp), default=0
-strong ................ use strong filter instead of simple (default)
-nostrong .............. use simple filter instead of strong
-partition_limit <int> . limit quality to fit the 512k limit on
@ -252,18 +253,18 @@ Options:
-print_ssim ............ prints averaged SSIM distortion
-print_lsim ............ prints local-similarity distortion
-d <file.pgm> .......... dump the compressed output (PGM file)
-alpha_method <int> .... transparency-compression method (0..1)
-alpha_method <int> .... transparency-compression method (0..1), default=1
-alpha_filter <string> . predictive filtering for alpha plane,
one of: none, fast (default) or best
-exact ................. preserve RGB values in transparent area
-exact ................. preserve RGB values in transparent area, default=off
-blend_alpha <hex> ..... blend colors against background color
expressed as RGB values written in
hexadecimal, e.g. 0xc0e0d0 for red=0xc0
green=0xe0 and blue=0xd0
-noalpha ............... discard any transparency information
-lossless .............. encode image losslessly
-lossless .............. encode image losslessly, default=off
-near_lossless <int> ... use near-lossless image
preprocessing (0..100=off)
preprocessing (0..100=off), default=100
-hint <string> ......... specify image characteristics hint,
one of: photo, picture or graph

33
examples/cwebp.c
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@ -521,9 +521,10 @@ static void HelpLong(void) {
printf("\nOptions:\n");
printf(" -h / -help ............. short help\n");
printf(" -H / -longhelp ......... long help\n");
printf(" -q <float> ............. quality factor (0:small..100:big)\n");
printf(" -alpha_q <int> ......... transparency-compression quality "
"(0..100)\n");
printf(" -q <float> ............. quality factor (0:small..100:big), "
"default=75\n");
printf(" -alpha_q <int> ......... transparency-compression quality (0..100),"
"\n default=100\n");
printf(" -preset <string> ....... preset setting, one of:\n");
printf(" default, photo, picture,\n");
printf(" drawing, icon, text\n");
@ -531,16 +532,20 @@ static void HelpLong(void) {
printf(" -z <int> ............... activates lossless preset with given\n"
" level in [0:fast, ..., 9:slowest]\n");
printf("\n");
printf(" -m <int> ............... compression method (0=fast, 6=slowest)\n");
printf(" -segments <int> ........ number of segments to use (1..4)\n");
printf(" -m <int> ............... compression method (0=fast, 6=slowest), "
"default=4\n");
printf(" -segments <int> ........ number of segments to use (1..4), "
"default=4\n");
printf(" -size <int> ............ target size (in bytes)\n");
printf(" -psnr <float> .......... target PSNR (in dB. typically: 42)\n");
printf("\n");
printf(" -s <int> <int> ......... input size (width x height) for YUV\n");
printf(" -sns <int> ............. spatial noise shaping (0:off, 100:max)\n");
printf(" -f <int> ............... filter strength (0=off..100)\n");
printf(" -sns <int> ............. spatial noise shaping (0:off, 100:max), "
"default=50\n");
printf(" -f <int> ............... filter strength (0=off..100), "
"default=60\n");
printf(" -sharpness <int> ....... "
"filter sharpness (0:most .. 7:least sharp)\n");
"filter sharpness (0:most .. 7:least sharp), default=0\n");
printf(" -strong ................ use strong filter instead "
"of simple (default)\n");
printf(" -nostrong .............. use simple filter instead of strong\n");
@ -557,19 +562,21 @@ static void HelpLong(void) {
printf(" -print_ssim ............ prints averaged SSIM distortion\n");
printf(" -print_lsim ............ prints local-similarity distortion\n");
printf(" -d <file.pgm> .......... dump the compressed output (PGM file)\n");
printf(" -alpha_method <int> .... transparency-compression method (0..1)\n");
printf(" -alpha_method <int> .... transparency-compression method (0..1), "
"default=1\n");
printf(" -alpha_filter <string> . predictive filtering for alpha plane,\n");
printf(" one of: none, fast (default) or best\n");
printf(" -exact ................. preserve RGB values in transparent area"
"\n");
printf(" -exact ................. preserve RGB values in transparent area, "
"default=off\n");
printf(" -blend_alpha <hex> ..... blend colors against background color\n"
" expressed as RGB values written in\n"
" hexadecimal, e.g. 0xc0e0d0 for red=0xc0\n"
" green=0xe0 and blue=0xd0\n");
printf(" -noalpha ............... discard any transparency information\n");
printf(" -lossless .............. encode image losslessly\n");
printf(" -lossless .............. encode image losslessly, default=off\n");
printf(" -near_lossless <int> ... use near-lossless image\n"
" preprocessing (0..100=off)\n");
" preprocessing (0..100=off), "
"default=100\n");
#ifdef WEBP_EXPERIMENTAL_FEATURES
printf(" -delta_palettization ... use delta palettization\n");
#endif // WEBP_EXPERIMENTAL_FEATURES

4
man/cwebp.1
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@ -1,5 +1,5 @@
.\" Hey, EMACS: -*- nroff -*-
.TH CWEBP 1 "June 23, 2016"
.TH CWEBP 1 "August 05, 2016"
.SH NAME
cwebp \- compress an image file to a WebP file
.SH SYNOPSIS
@ -171,7 +171,7 @@ Specify the amplitude of the spatial noise shaping. Spatial noise shaping
(or \fBsns\fP for short) refers to a general collection of built\-in algorithms
used to decide which area of the picture should use relatively less bits,
and where else to better transfer these bits. The possible range goes from
0 (algorithm is off) to 100 (the maximal effect). The default value is 80.
0 (algorithm is off) to 100 (the maximal effect). The default value is 50.
.TP
.BI \-segments " int
Change the number of partitions to use during the segmentation of the

4
src/dsp/rescaler.c
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@ -173,10 +173,10 @@ void WebPRescalerExportRow(WebPRescaler* const wrk) {
WebPRescalerExportRowExpand(wrk);
} else if (wrk->fxy_scale) {
WebPRescalerExportRowShrink(wrk);
} else { // very special case for src = dst = 1x1
} else { // special case
int i;
assert(wrk->src_height == wrk->dst_height && wrk->x_add == 1);
assert(wrk->src_width == 1 && wrk->dst_width <= 2);
assert(wrk->src_height == 1 && wrk->dst_height == 1);
for (i = 0; i < wrk->num_channels * wrk->dst_width; ++i) {
wrk->dst[i] = wrk->irow[i];
wrk->irow[i] = 0;

8
src/utils/rescaler.c
View File

@ -48,11 +48,15 @@ void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
wrk->y_sub = wrk->y_expand ? y_sub - 1 : y_sub;
wrk->y_accum = wrk->y_expand ? wrk->y_sub : wrk->y_add;
if (!wrk->y_expand) {
// this is WEBP_RESCALER_FRAC(dst_height, x_add * y_add) without the cast.
// This is WEBP_RESCALER_FRAC(dst_height, x_add * y_add) without the cast.
// Its value is <= WEBP_RESCALER_ONE, because dst_height <= wrk->y_add, and
// wrk->x_add >= 1;
const uint64_t ratio =
(uint64_t)dst_height * WEBP_RESCALER_ONE / (wrk->x_add * wrk->y_add);
if (ratio != (uint32_t)ratio) {
// We can't represent the ratio with the current fixed-point precision.
// When ratio == WEBP_RESCALER_ONE, we can't represent the ratio with the
// current fixed-point precision. This happens when src_height ==
// wrk->y_add (which == src_height), and wrk->x_add == 1.
// => We special-case fxy_scale = 0, in WebPRescalerExportRow().
wrk->fxy_scale = 0;
} else {