[empathy: 1/2] Explain how to load custom GStreamer plugins

[Guillaume Desmottes <gdesmott src gnome org>]

commit a1461f4f6185a2a17f6e5e80924107fc9fc4bded
Author: Emanuele Aina <emanuele aina collabora com>
Date:   Tue Mar 13 10:59:48 2012 +0100

    Explain how to load custom GStreamer plugins

 HACKING |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/HACKING b/HACKING
index b486e33..073f9f2 100644
--- a/HACKING
+++ b/HACKING
@@ -20,5 +20,16 @@ channel to handle. For example:
 Debugging can be turned on using EMPATHY_DEBUG=all and logged to a file
 with EMPATHY_LOGFILE=/tmp/empathy.log
 
+Sometimes you may want to load the locally compiled version of some GStreamer
+plugin (e.g. Farstream) instead of the system installed one. To do so, just
+set the GST_PLUGIN_PATH environment variable to tell GStreamer where your
+plugins are located and the GST_PLUGIN_LOADING_WHITELIST to avoid conflicts
+with system installed plugins. It's also a good idea to use GST_REGISTRY to
+avoid clobbering your default GStreamer registry. For example you can
+export these before launching the empathy processes as shown above:
+  export GST_PLUGIN_LOADING_WHITELIST=gstreamer:gst-plugins-base:gst-plugins-good:libnice:valve:siren:autoconvert:rtpmux:dtmf:mimic:shm
+  export GST_PLUGIN_PATH=/path/to/your/custom/lib/gstreamer-0.10
+  export GST_REGISTRY=/tmp/gstreamer.registry
+
 See http://live.gnome.org/Empathy/ about coding style conventions.
 See also http://live.gnome.org/Empathy/Git to read about our git workflow.