Comment 3 for bug 144110

Yes, the problem is the same when launching manually.

A good example video can be downloaded (via bittorrent) from this url: http://www.anime-kraze.org/torrent/%5BA-Kraze%5D_Seirei_no_Moribito_-_23_%5B75667171%5D.mkv.torrent
Launch the mkv file and you should encounter stuttering playback/short drops in framerate after 10-15 seconds of playback. When watching carefully (and ignoring the silly soundtrack) you should also see greenish screen glitches to the left border of the playback window (ca. 1:17 playback).

This problem is not limited to this file, I encounter it when playing any file with mp4 codec.