Problems with ubuntu 14.04

[Lyr3x]

I installed all dependencies fine, when i execute python jarvis.py this error is instantly following:
/usr/local/lib/python2.7/dist-packages/pydub/utils.py:122: RuntimeWarning: Couldn't find ffmpeg or avconv - defaulting to ffmpeg, but may not work warn("Couldn't find ffmpeg or avconv - defaulting to ffmpeg, but may not work", RuntimeWarning)

Then Jarvis is listening and each 10 seconds he said: Sorry Sir, im unable to process that

[DanielAndreasen]

I got rid of this error by installing the libav-tools

apt-get install libav-tools