I have a blu-ray rip and I'd like to convert the DTS-HD audio to wav or flac files. I would like to keep each of the 5.1 tracks, not downmix to stereo.

What I've tried:

makemkv- I used this to create a mkv with FLAC audio. This program will convert the DTS-HD to 5.1 FLAC as part of a MKV, but I don't think it's able to save just the FLAC file.

I then used imkvextract to extract just the FLAC file from the MKV. However, I'm given a file with .??? as the extension and no decoder programs see it as a valid FLAC file, even after renaming. VLC plays it and reports that the audio is 5.1 FLAC. But I haven't been successful in using VLC to transcode to 5.1 wav, only a stereo downmix.

Any help would be appreciated. Thanks!