Confused last step of installation

[ugintl]

Installation went good, but it showed an error, screenshot attached.

Secondly, I am confused in the last step where video transcoding option needs to be selected. I do not want to use zencoder. If I use ffmpeg, what should be the path? By default it is showing /usr/bin/ffmpeg. Currently I am developing site with acquia dev and then use it on pantheon hosting.

Can you tell me about the pros and cons of using and not using zencoder or ffmpeg or not using transcoding at all?