Batch convert video soundtrack AAC -> AC-3 with MP4tools problems

[mrtn]

Hi!

I have a bunch of mp4 files with AAC 5.1 sound that I would like to convert to AC-3 5.1.
I would like to batch convert the sound and Pass Thru the video.
So far I have tried MP4tools. I have set the video to Pass Thru, even so it says "Video Conversion 5%..." is that just the time it takes to copy it?
It would also be great if it could automatically delete the original file and just skip the files that only have stereo instead of doing pass through on those too.

In the log it seems like it's going through all the frames of the video track.

I'm on OS X.
Any faster way to do this?

Best,
Martin

Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (aac -> ac3)
Stream #0:2 -> #0:2 (mov_text -> mov_text)
Stream #0:3 -> #0:3 (mov_text -> mov_text)
Stream #0:4 -> #0:4 (mov_text -> mov_text)
Press [q] to stop, [?] for help
frame= 26 fps=0.0 q=-1.0 size= 0kB time=00:00:00.98 bitrate= 0.4kbits/s
Encoder did not produce proper pts, making some up.
frame= 29 fps= 25 q=-1.0 size= 0kB time=00:00:01.08 bitrate= 0.4kbits/s
frame= 35 fps= 20 q=-1.0 size= 0kB time=00:00:01.33 bitrate= 0.3kbits/s
frame= 47 fps= 19 q=-1.0 size= 0kB time=00:00:01.85 bitrate= 0.2kbits/s
frame= 211 fps= 64 q=-1.0 size= 0kB time=00:00:08.69 bitrate= 0.0kbits/s
frame= 320 fps= 81 q=-1.0 size= 0kB time=00:00:13.24 bitrate= 0.0kbits/s
frame= 520 fps=109 q=-1.0 size= 3153kB time=00:00:21.56 bitrate=1198.0kbits/s
frame= 592 fps=109 q=-1.0 size= 5068kB time=00:00:24.57 bitrate=1689.8kbits/s
frame= 634 fps=102 q=-1.0 size= 5827kB time=00:00:26.33 bitrate=1812.8kbits/s
frame= 634 fps= 77 q=-1.0 size= 5827kB time=00:00:26.36 bitrate=1810.6kbits/s
frame= 857 fps= 85 q=-1.0 size= 11822kB time=00:00:35.64 bitrate=2717.2kbits/s

[mrtn]

Oh well, I'll just stick with this since it works.
Maybe this thread can help someone else. If admin feels that it won't feel free to delete.