[FFmpeg-user] HW acceleration and ffmpeg

[vpstranger at tutanota.com]

Hello! 
I have a couple of questions about ffmpeg tool. 
When I use the ffmpeg tool that was compiled with support of one of the hardware accelerators, will the tool automatically use this acceleration while working? Or it has to be explicitly specified somehow that it must be used? 
And if it attempts to use it, how do I check whether that attempt was successful?