Comment # 1 on bug 977903 from Mikhail Kasimov

Variants of solution:

1. To check, if gstreamer-plugins-libav is not installed, then generate message
like 'gstreamer-plugins-libav is not installed. Please, install it to play this
file' after then exit ().

2. To check, if gstreamer-plugins-libav is not installed, then generate message
like 'gstreamer-plugins-libav is not installed. If you press 'Yes', you'll hear
the sound, but won't see video-stream. 'No' is recommended. Please, install
gstreamer-plugins-libav to play video-stream normally'. And two buttons --
'Yes' and 'No'. But in this case it's anyway needed to avoid memory-leak if
user chooses 'Yes'.

So, 1. is more lazy way and 2. is more intelligent.