Because video can be viewed both vertically and horizontally on devices, choosing video dimensions for playback is complicated.
There are three approaches to vertical screen positioning of video on devices.
1. Scale to maximum screen width of device.
This is not recommended because:
- Scaling the video makes already small images even smaller
- Requires additional CPU resources to scale the video
- Requires full resolution video to be downloaded, only to be scaled down.
2. Request a version of the encoded video that fits the screen width.
This approach is better, because a version of the file in a more optimal 4:3 aspect ratio can be used.
- Requires player logic to detect screen orientation and swap in appropriate video file.
3. Fit the video to the screen dimensions without scaling.
Scenario three is very similar to scenario two with one exception - it does not scale video to fit the screen, but rather keeps it in its natively encoded resolution.
For more information, see Encoding Guidelines for Android™ Powered Devices, page 17 ( http://www.adobe.com/devnet/devices/articles/encoding-guidelines-android.html)