H.264: Using High versus Main profile

A common question for many users is what level profile to use with H.264 encoding for web streaming.

Baseline - for low definition (LD) 320x240 or smaller, compatible with older 3G mobiles
Main - for standard definition (SD) to 640x480, good for modern smartphones and tablets
High - for high definition (HD) to 1920x1080, best for big screens with a good decoder