iFunia iPhone Video Converter is a commercial video converter. It was designed for iPhone users, to let them convert video files that can't be played on the iPhone to more Apple-friendly formats, such as H.264, MPEG-4 and MOV. The app can also convert video files to audio files; a process that discards the video track entirely. This is useful when you want to rip the audio out of music videos or concerts.
This application has a very nice user interface. It has a big space where your files to be converted are listed, a video player on the right, and the conversion settings on top of it. There are five conversion profiles for the iPhone 4 and one for general video playback on iPhone devices. Some of the profiles support 720p and 1080p resolutions.
There is a video editor that allows you to trim and crop your videos and adjust their brightness, contrast and saturation.
In my testing, I converted a 1-minute MKV video into the 720p H.264 profile. The app took roughly 1 second to convert every second of video, which is not entirely bad. There are faster apps out there, but there are also slower ones. The resulting file looked very good.
I noticed a problem with 5.1 DTS MKV files. For some reason, the central channel wasn't converted, so I couldn't hear any voices.