I am new to this conversion process as I am trying to convert all my MKVs to M4V to have them playback using ATV3. Handbrake takes a lot of time even though my MKVs are x264 video with DTS audio. What I so far understand is it should be easy to convert a video from mkv to m4v if codec is x264 in source file. So I was kind of hoping to passthru video and only convert DTS to AC3 multichannel so to save some time doing the conversions. I did not find a way to do this with HB , so was wondering is there a way or program that would just pass thru video and only convert audio ? I am not very well versed with this but would love to learn more.