This page contains details and explainations for the options in the Preferences dialog. These will help you configure and customize Avidemux more to your liking when you are using it.
Some changes require a restart to be taken into account, especially the audio and video decoding/displaying options.
ALSA device(nbsp)(ndash) see the Audio output → ALSA subsection.
Local Playback Downmixing(nbsp)(ndash) enable use of downmixing or sound alteration for certain sound environments. You can set the way a multichannel audio will be downmixed when played inside Avidemux. If you have a 5.1 speaker soundsystem and an audio-device that supports it, you might want to select “no downmixing.” Otherwise the multichannel audio will be downmixed to either Dolby Pro Logic 1 or 2.
Volume bar controls:
Post processing happens after the video frames have been created. Some users strongly recommend disabling all of these options as they can interfere with more complex operations, particularly with filtering involving interlacing and noise.
See the Multithreading article.