IPad – Which mkv player for iPad mini

Yes, I would recommend to convert it to a format that iMove can import. MKV is just a container format so you probably already have an iMovie-compatible inside that package. Under Snow Leopard just install Perian and open it in QuickTime X and then go to File->Save as ... and choose a suitable format from the dropdown menu.

If you need more control over your conversion, you could also convert it to an iMovie-compatible format using any of the video conversion tools available for the Mac. For a long time VisualHub was the king of video format conversion, unfortunately techspansion the company behind it, closed its virtual doors. There are two main open-source options derived from VisualHub, ReduxZero and TranscoderRedux they both should do the trick. Another option is Subler which will also convert to and from MKV video containers to an iMovie-compatible format.

(HD-)MKVs require a lot more processing power than the iPad can offer. Bear in mind that all the decoding in VLC for iOS is done in software...iOS devices only have H.264/MP4 hardware decoding support - and VLC is not using it, even for files in said format. If you want to watch HD files on your iPad, you need to reencode them to H.264 in a MP4 container and watch them using the iOS video player.