From b90210e9c5ea365befef61b10b9a34ce37f9e679 Mon Sep 17 00:00:00 2001 From: Tim Nicholson Date: Wed, 19 Sep 2012 09:02:01 +0100 Subject: [PATCH] doc/filters: clarify use of graph2dot The GRAPH_DESCRIPTION string supplied to graph2dot must include explicitly defined inputs and outputs which are not normally part of the command line used in a real invocation. This clarifies that requirement, and provides an example. Signed-off-by: Stefano Sabatini --- doc/filters.texi | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/doc/filters.texi b/doc/filters.texi index 60b240d5d4..e202d383d9 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -79,7 +79,18 @@ display graph.png @end example can be used to create and display an image representing the graph -described by the @var{GRAPH_DESCRIPTION} string. +described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be +a complete self-contained graph, with its inputs and outputs explicitly defined. +For example if your command line is of the form: +@example +ffmpeg -i infile -vf scale=640:360 outfile +@end example +your @var{GRAPH_DESCRIPTION} string will need to be of the form: +@example +nullsrc,scale=640:360,nullsink +@end example +you may also need to set the @var{nullsrc} parameters and add a @var{format} +filter in order to simulate a specific input file. @c man end GRAPH2DOT