[FFmpeg-devel] [PATCH] Clarifying the use of the scale filter interlace option

Tim Nicholson nichot20 at yahoo.com
Mon Mar 26 18:37:47 CEST 2012


Based upon some recent queries on ffmpeg-user, and my own experience, a little
clarification of the documentation should help users in this area.

-- 
Tim

>From a9c2a766e0f94105004ca467902519dfd123053f Mon Sep 17 00:00:00 2001
From: Tim Nicholson <Tim.Nicholson at bbc.co.uk>
Date: Mon, 26 Mar 2012 17:22:16 +0100
Subject: [PATCH] Clarify the use of the interl=1|-1 option of the scale
 filter.

It is not entirely clear that whilst for width and height only an
expression needs to be provided, for interlace the option must
also be given.

It is also unclear that the default is non interlaced aware scaling.
---
 doc/filters.texi |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/doc/filters.texi b/doc/filters.texi
index ac3e841..6c6d439 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -2280,6 +2280,8 @@ select interlaced aware scaling depending on whether the
source frames
 are flagged as interlaced or not
 @end table

+Unless @var{interl} is set to one of the above options, interlaced scaling will
not be used.
+
 Some examples follow:
 @example
 # scale the input video to a size of 200x100.
@@ -2290,6 +2292,9 @@ scale=2*iw:2*ih
 # the above is the same as
 scale=2*in_w:2*in_h

+# scale the input to 2x with forced interlaced scaling
+scale=2*iw:2*ih:interl=1
+
 # scale the input to half size
 scale=iw/2:ih/2

-- 
1.7.7



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