Video editing

I have a few questions about the sequence editor in blender.

1.) How do I select which codecs to use when I select FFmpeg in the rendering panel?

2.) Whenever I add a movie file with audio, the audio track is always longer than the actual movie file. I’ve tried changing the framerate but it doesn’t help. Why does it do this?

3.) Whenever I play a video in the sequence editor the sound doesn’t play even though I’ve selected the playback audio button and used the ‘-g nosound’ option. In the console it says that it can’t open the audio device. How do I enable sound? I am using linux by the way.