From 9b5a98676d18156d56fabae52dbc1d918e4401d4 Mon Sep 17 00:00:00 2001
From: Martin Herkt <lachs0r@srsfckn.biz>
Date: Sat, 15 Jun 2013 15:14:06 +0200
Subject: image_writer: Add PNG filter option (default "mixed")

The use of filters prior to PNG compression can greatly improve
compression ratio, with "mixed" (ImageMagick calls it "adaptive")
typically achieving the best results.
---
 DOCS/man/en/options.rst | 6 ++++++
 DOCS/man/en/vo.rst      | 3 +++
 2 files changed, 9 insertions(+)

(limited to 'DOCS/man')

diff --git a/DOCS/man/en/options.rst b/DOCS/man/en/options.rst
index f8a999758e..516d485c7e 100644
--- a/DOCS/man/en/options.rst
+++ b/DOCS/man/en/options.rst
@@ -1791,6 +1791,12 @@
     to write a screenshot. Too high compression might occupy enough CPU time to
     interrupt playback. The default is 7.
 
+--screenshot-png-filter=<0-5>
+    Set the filter applied prior to PNG compression. 0 is none, 1 is "sub", 2 is
+    "up", 3 is "average", 4 is "Paeth", and 5 is "mixed". This affects the level
+    of compression that can be achieved. For most images, "mixed" achieves the
+    best compression ratio, hence it is the default.
+
 --screenshot-template=<template>
     Specify the filename template used to save screenshots. The template
     specifies the filename without file extension, and can contain format
diff --git a/DOCS/man/en/vo.rst b/DOCS/man/en/vo.rst
index 251e71ce03..079e146f8a 100644
--- a/DOCS/man/en/vo.rst
+++ b/DOCS/man/en/vo.rst
@@ -708,6 +708,9 @@ image
 
     png-compression=<0-9>
         PNG compression factor (speed vs. file size tradeoff) (default: 7)
+    png-filter=<0-5>
+        Filter applied prior to PNG compression (0 = none; 1 = sub; 2 = up;
+        3 = average; 4 = Paeth; 5 = mixed) (default: 5)
     jpeg-quality=<0-100>
         JPEG quality factor (default: 90)
     [no-]jpeg-progressive
-- 
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