Converting Mpeg-4 and AVI videos on laptop to upload and view on device full screen

[David Malinowski]

I've realized that most with videos on sites, you are given the option to use "Video Player" or "Download". either way the screen is about 3/4'' by 3/4''.
I download "Free" software that will supposedly do this but it will only convert the first 10 seconds until you pay for full version.

Any Ideas on low to view video files full screen on my s5?