Camera acquisition on Raspberry Pi, shutter, ISO and exposure controls and sink video/x-raw in GStreamer pipeline

GStreamer element : gstmmalsrc

This element gets frames from camera using MMAL API.

How to install GStreamer

First you have to install required packages. If you use Debian 6, you can install them with the provided script

./scripts/install_prereq.sh

Otherwise, look for each package in your package manager and install them.

Then you can install GStreamer 1.10 in your home directory (${HOME}/gstreamer)

./scripts/build_gstreamer.sh

If you want to re-start compilation from scratch or to remove GStreamer installation, you just have to remove this directory

rm -rf ~/gstreamer

How to compile the project

First make sure you have the cmake package installed on your system.

To compile the gstplugins, you can run these commands :

source scripts/env.sh
rm -rf build
mkdir -p build
cd build
cmake ..
make

Then you should see the plugin libgstmmal.so in your build directory. You can check that this is a correct GStreamer plugin

gst-inspect-1.0 ${PWD}/libgstmmal.so

How to install the plugin

To install it with other plugins

cp libgstmmal.so ~/gstreamer/install/usr/local/lib/gstreamer-1.0/

To force detection/parsing of GStreamer plugin, you need to delete the cache. Note that the name of the registry may change depending on your system.

rm ~/.cache/gstreamer-1.0/registry.x86_64.bin

Then you can check that the plugin is usable

gst-inspect-1.0 mmalsrc

How to use the plugin

The mmalsrc is a source element. You can test it with gst-launch

source scripts/env.sh
gst-launch-1.0 mmalsrc shutter-activation=on shutter-period=10000 exposure=on ISO=400 \
    ! video/x-raw,format=RGBA,width=640,height=360,framerate=30/1 \
	! videoconvert \
    ! fbdevsink

To display debug message from this element, use the environment variable

export GST_DEBUG="mmalsrc:5"