Tips for converting videos for DVD player playback using Avidemux -
1. A very simple fix for avidemux "Trouble initialising audio device" -
Go to "tools->preferences->audio->alsa device" and change it to "default" instead of "dmix"
Wonder why "default" is not the default for that setting!
2. Best encoding settings for playback on a DVD player -
Video - MPEG-4 ASP (Xvid4)
Audio - MP3 (LAME)
3. If you get an error "Encoder not initialised" then most probably the input audio frequency is non standard. Turn on "Audio->Filters->Resampling (Hz)" and that should fix the problem.