Ubuntu Multimedia :: Nuendo Alternatives For Voice Over

I want to do some amateur voice over works. I need an audio editor that can also play the video simultaneously to sync with the character's lip movements.The problem is my video sources are in h264 mkv, I guess it is not very friendly with many softwares.

Here's what I've searched (tried some of them too) and the results:LiVES -> can't compile with kernel 2.6.38, the offered patch (in sf) rejected (maybe different source file from the one specified in the patch)Cinerella, can't accept mkv or mp4. (after that I tried to get the source video loaded to Cinerella)x264, transcoding to lower the resolution -> no avi container output, sync problem with raw h264 stream outputavidemux_qt, trying to mux the transcoded video to avi -> crashed with h264 input video, either in elementary stream or matroska format (I doubt Cinerella will accept avi videos with h264 codec, if I could ever make one)ffmpeg, transcode from h264 to xvid -> shared library error: libavutil.so.49 not found xvidenc shell script -> no mencoder (I'm using mplayer2)