[pitivi] help: add Animating effects with keyframes section to usingeffects.page

[Jean-François Fortin Tam <jfft src gnome org>]

commit 3dd429d8d9ac708da751273f8db09716a51504a8
Author: Tomas Karger <tomkarger gmail com>
Date:   Tue Mar 25 17:39:49 2014 +0100

    help: add Animating effects with keyframes section to usingeffects.page

 help/C/usingeffects.page |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/help/C/usingeffects.page b/help/C/usingeffects.page
index 3cad827..ba06b82 100644
--- a/help/C/usingeffects.page
+++ b/help/C/usingeffects.page
@@ -27,4 +27,11 @@
         <title>Configuring effects</title>
         <p>To configure an effect, simply select it in the <guiseq><gui>middle pane</gui><gui>Clip 
configuration</gui> <gui>Effects</gui></guiseq>. Variables that can be adjusted will appear in the lower part 
of the <gui>Clip configuration</gui> tab. Each variable can be put back to it's original value by clicking 
the corresponding <gui>Reset to default value</gui> button.</p>
     </section>
+    <section>
+        <title>Animating effects with keyframes</title>
+        <p>Most effect variables can be controlled with keyframes. In order to access the keyframes, click 
the <gui>Show keyframes for this value</gui> button next to the variable you want to control. On the selected 
clip you will see a keyframe curve that belongs to the variable. You can now edit the keyframes to achieve 
the desired effect. Once you are done with editing, you can click the button again and the keyframe curve 
disappears from the clip. However, the effect variable is still controlled by the adjusted keyframe curve 
(which is indicated by the filled shape on the button). To revert the keyframe curve to the default flat 
state, use the <gui>Reset to default value</gui> button. For more information on how to use keyframes see the 
<link xref="keyframecurves">Keyframe curves</link> page.</p>
+        <note>
+            <p>If there is no <gui>Show keyframes for this value</gui> button next to the effect variable, 
it can not be controlled with keyframes.</p>
+        </note>
+    </section>
 </page>