Sorry if this is the wrong place for this post, but since Im converting for use with my ATV I figure someone else may have come across this problem. I am using MP4 Tools to quickly batch convert files to mp4 for iTunes. I used to use handbrake, but it takes forever and someone here mentioned mp4 tools. MP4 tools works much better when it works. Most of the time mp4 tools works ok, every once in a while I will find some mkv files it refuses to open. It opens some mkv files fine, but just spits others out. Any ideas on whats happening or what I might be doing wrong?