I am using ffmpeg to encode videos with H264-AVC codec and MPEG-4 container.
From now, I have always been trying to make the same effort for videos than for drawables: providing the proper resolution for each kind of devices.
That's why I used to add videos in raw-mdpi / raw-hdpi / raw-xhdpi folders respectively with resolutions 240x320 / 480x800 / 720x1280.
I was thinking to be right, until I discovered videos encoded in 480x800 (located in my raw-hdpi folder) were unsupported on Nexus S (for this device, I need to use 480x720).
Reading http://developer.android.com/guide/practices/screens_support.html#range, I thought the solution was rather to use raw-normal / raw-large / raw-xlarge folders with minimum resolutions: 320x470 / 480x640 / 720x960. But then i saw that most of my HDPI devices where using videos in the raw-normal folder.
So I think I am totally misunderstanding the proper way to do, that's why I would really appreciate some explanations, and most of all, your practices with video encoding: do you only provide videos with the minimum resolution to be certain to support all devices, or the "proper" resolution for each kind of devices?