how I can use mkv video in final cut

You can convert it to an edit format that FCP will work with first. DO you have Perian installed? If so you should be able to easily open the clips up in MPEG Streamclip ( a popular app for handling such conversions ) and use the FIle > Export to Quicktime function to convert the clips to a better handled supported edit format for FCP. I'd recommend you choose Compressor : Apple ProRes LT in the Export to Quicktime Settings dialog.

Hope it helps

Andy

mocikuo wrote:

Why MPEG Streamclip is useless to me? Do I need other softwares like HandBrake or B-r-o-rsoft?

You are posting in a thread that has been dormant for five years. You're going to get more and better answers if you start your own thread with a properly descriptive subject line.