[FFmpeg-devel] [PATCH v3] doc/demuxers: document gif demuxer

[Lou Logan]

New patch inserted below.

On Tue, 2 Sep 2014 16:50:49 -0700, Timothy Gu wrote:

> On Aug 31, 2014 3:16 PM, "Lou Logan" <lou at lrcd.com> wrote:
> 
> > + at item ignore_loop
> 
> > +GIF files can be set to loop infinitely or up to a certain number of
> > +times.
> 
> can contain information to loop...
> 
> "Can be set" sounds like settable from a ffmpeg command.

Changed.

> > +This option prevents a GIF stream from looping forever.
> 
> Not necessary. Covered in the second paragraph above.

Removed.

> > +Default value is 1.
> 
> 5 paragraphs for this trivial option? Ouch.

Squashed into one.

> > + at end table
> > +
> > +For example, with the overlay filter, place an infinitely looping GIF
> > +over another video:
> > + at example
> 
> > +ffmpeg -i input.mp4 -ignore_loop 0 -i input.gif
> >  -filter_complex overlay=shortest=1 out.mkv
> 
> What if input.gif contains information saying that it should only be looped
> once? Doesn't this command break then?

The text above and below the actual example both indicate that the input GIF
loops infinitely.

I could remove the whole example section if it is too confusing.

> Rest LGTM.
> 
> Timothy

New patch inserted below:

From d95991c4dd423cc4bc231510255f74dda600afbc Mon Sep 17 00:00:00 2001
From: Lou Logan <lou at lrcd.com>
Date: Thu, 28 Aug 2014 16:26:11 -0800
Subject: [PATCH] doc/demuxers: document gif demuxer

Signed-off-by: Lou Logan <lou at lrcd.com>
---
 doc/demuxers.texi | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/doc/demuxers.texi b/doc/demuxers.texi
index d51b9d0..e582322 100644
--- a/doc/demuxers.texi
+++ b/doc/demuxers.texi
@@ -174,6 +174,40 @@ See @url{http://quvi.sourceforge.net/} for more information.
 FFmpeg needs to be built with @code{--enable-libquvi} for this demuxer to be
 enabled.
 
+ at section gif
+
+Animated GIF demuxer.
+
+It accepts the following options:
+
+ at table @option
+ at item min_delay
+Set the minimum valid delay between frames in hundredths of seconds.
+Range is 0 to 6000. Default value is 2.
+
+ at item default_delay
+Set the default delay between frames in hundredths of seconds.
+Range is 0 to 6000. Default value is 10.
+
+ at item ignore_loop
+GIF files can contain information to loop a certain number of times (or
+infinitely). If @option{ignore_loop} is set to 1, then the loop setting
+from the input will be ignored and looping will not occur. If set to 0,
+then looping will occur and will cycle the number of times according to
+the GIF. Default value is 1.
+ at end table
+
+For example, with the overlay filter, place an infinitely looping GIF
+over another video:
+ at example
+ffmpeg -i input.mp4 -ignore_loop 0 -i input.gif -filter_complex overlay=shortest=1 out.mkv
+ at end example
+
+Note that in the above example the shortest option for overlay filter is
+used to end the output video at the length of the shortest input file,
+which in this case is @file{input.mp4} as the GIF in this example loops
+infinitely.
+
 @section image2
 
 Image file demuxer.
-- 
2.0.4