Batch transcode in advance

[atc98092]

Does anyone know of a simple way to transcode a file to change the video from MPEG to H.264, preferably via a batch file? Since both the Roku and my Sony players will play H.264 natively, I was looking for a way to update them all. The issue is I have well over 1500 videos that would need to be changed, and I'm not going to try to do them all manually! Also, I don't want to lose my ability to toggle subtitles in the files that have them. All of my videos are currently in an MKV container. The Roku will only play MKV and MP4 natively, and for some strange reason it doesn't support MPEG2 video. Of course, what are all my DVD rips? MPEG2!

For audio, the Roku will passthrough AC3 and DTS, as long as the container is MKV. That pretty much requires me to stick with MKV. The Sony will play HD audio, but since the Roku can't select audio streams, the default audio must not be HD.

Transcoding on the fly to satisfy the Roku causes my quad core CPU to run about 95%, and while there are no playback issues, I worry that I really don't have much overhead left for playing additional streams.