DTS 6.1 (7 Channel) to 5.1 AC3 possible?

[ninethirty]

I'm trying to convert a file with 7 channel audio (6.1 DTS) to 5.1 AC3 with command line ffmpeg, but I get this error:

Input stream #0.1 frame changed from rate:48000 fmt:s16 ch:7 to rate:48000 fmt:s16 ch:6
Resampling with input channels greater than 2 unsupported.
Can not resample 6 channels @ 48000 Hz to 6 channels @ 48000 Hz

This is the line I'm using:

ffmpeg -i file.mkv -acodec ac3 -ac 6 -ar 48000 -ab 640k -vcodec copy file.m4v

I also tried using MKVTools (mac) for the hell of it and it clearly didn't work as it said the audio conversion was done in a half second.

Any ideas? Thanks in advance!

[dragonkeeper]

On a Mac, I don't know of any 1 click free tools that will let you do this, will probably be a manual process.

Doing this manually. You would need to de-mux the audio stream to 7 separate tracks, then combine/convert Front, rear and LFE channels into a 5.1 AC3. I don't know which tools that will allow you to do this on a Mac.

If you are using and Intel based Mac you could do a dual boot and install a version of windows and use E-ac3 to convert the file.

[jman98]

Why are you "resampling" from 48000 Hz to 48000 Hz? The error message clearly states that ffmpeg has a problem with this. I'm not an ffmpeg expert but I'd guess that dropping "-ar 48000" from your command would be at the minimum a step in the right direction if not a complete fix for the problem.