README.rst: Update gstreamer element guidance

The Gstreamer gstlibcamerasrc element operates better with the
glimagesink, as it can perform direct renders or hardware accellerated
image format conversion.

Further extend the sample commands to demonstrate how to specify a fixed
width and height parameter to the pipeline.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 18 insertions, 3 deletions

diff --git a/README.rst b/README.rst
index fcf0f47f..cf81eca4 100644
--- a/README.rst
+++ b/README.rst
@@ -94,17 +94,32 @@ Using GStreamer plugin
 ~~~~~~~~~~~~~~~~~~~~~~
 
 To use GStreamer plugin from source tree, set the following environment so that
-GStreamer can find it.
+GStreamer can find it. This isn't necessary when libcamera is installed.
 
   export GST_PLUGIN_PATH=$(pwd)/build/src/gstreamer
 
 The debugging tool ``gst-launch-1.0`` can be used to construct a pipeline and
 test it. The following pipeline will stream from the camera named "Camera 1"
-onto the default video display element on your system.
+onto the OpenGL accelerated display element on your system.
 
 .. code::
 
-  gst-launch-1.0 libcamerasrc camera-name="Camera 1" ! videoconvert ! autovideosink
+  gst-launch-1.0 libcamerasrc camera-name="Camera 1" ! glimagesink
+
+To show the first camera found you can omit the camera-name property, or you
+can list the cameras and their capabilities using:
+
+.. code::
+
+  gst-device-monitor-1.0 Video
+
+This will also show the supported stream sizes which can be manually selected
+if desired with a pipeline such as:
+
+.. code::
+
+  gst-launch-1.0 libcamerasrc ! 'video/x-raw,width=1280,height=720' ! \
+        glimagesink
 
 .. section-end-getting-started