Enc: add a qmin / qmax range for quality factor

This is particularly useful for multi-pass search (but not only),
to prevent the search from going over or below a reasonable threshold.
E.g.: 'cwebp -qrange 50 80 ...' will prevent any unreasonable degradation.

new cwebp option: -qrange min max

Change-Id: I59f394533535fc20b6996bc0895f4301476d5eff
This commit is contained in:
Skal
2020-01-29 09:34:26 +01:00
parent 0fa56f307f
commit 6a0ff35872
6 changed files with 64 additions and 36 deletions

View File

@ -134,6 +134,13 @@ options \fB\-size\fP or \fB\-psnr\fP. Maximum value is 10, default is 1.
If options \fB\-size\fP or \fB\-psnr\fP were used, but \fB\-pass\fP wasn't
specified, a default value of '6' passes will be used.
.TP
.BI \-qrange " int int
Specifies the permissible interval for the quality factor. This is particularly
useful when using multi-pass (\fB\-size\fP or \fB\-psnr\fP options).
Default is 0 100.
If the quality factor is outside this range, it will be clamped.
If the minimum value must be less or equal to the maximum one.
.TP
.B \-af
Turns auto\-filter on. This algorithm will spend additional time optimizing
the filtering strength to reach a well\-balanced quality.