WinX MKV to iPhone Video Converter for Mac - Free edition is a free converter. It can be used to convert MKV files into files that can be played on your iPhone, and any other device that will play the H.264 or MPEG-4 formats. iPods, the Apple TV and iPads will play those formats just fine, and so will most modern computers and multimedia playback devices.
MKV is one of the most popular formats for the distribution of high definition content. It is an open-source container format that can accomodate multiple audio tracks, subtitle tracks and high resolution video tracks. When I want to convert an MKV file to other formats, there are a few things that I look for in a converter. First, the quality of the converted file has to be similar to that of the original one. This converter passes that test. There will be quality loss. Any conversion results in at least a bit of loss. But the files looked good. Second, I want to be able to convert multiple audio tracks, or rip them to audio files, if conversion isn't possible. This converter can also do that. The third thing that I look for is support for subtitles, and this one doesn't support them.
In my testing, the converter worked good enough. It crashed once when I was processing a dual-audio file. But converted the file just fine on the second try.