Unplayabe audio when encoding to Flac, Alac works fine...

[ajstrobus]

FastFlix Version:
5.6.0
Operating System:
Windows 11 R23H2v2
Describe the bug
Converting single default audio DTS-HD MA 5.1 track in video as flac is unplayable
To Reproduce
mkv with Bluray Remux With Any Audio I've tried (TrueHD or DTS-HD 7.1 or 5.1) convert to Flac (have tried -no downsample, 5.1 downmix, or stereo) when finished audio is unplayable in VLC or likely anything else. Mkvtoonix sees the only Flac audio track correctly as default enabled, MkvExtracting it out alone still doesn't play.
Possible Solution
in FFmpeg when i do -map 0:a:m:language:eng and -c:a flac -compression_level 5 -sample_fmt s16 -ac 6 (this makes a great compressed 16bit 6ch flac) maybe this can be integrated into Fastflix, my map command seems to select all english audio though not just the first, not sure what command handbrake uses but it grabs the first audio per language & encodes to flac perfect if there's a way to find what command handbrake uses I can't see it in logs
Logs (If applicable) In FastFlix you can go to Help > Open Log Directory and sort by latest to find the newest log file to add here.
flix_conversion_file_2024-01-16T20.57.07.log