I hear that Audacity is not able to detect TRUEHD. Is this true? Because when I import my MKV file (which has TRUEHD audio within it) into Audacity, everything imports successfully.
Does this mean that Audacity is automatically converting this TRUEHD audio into something else upon import? If so, do you know what audio type it is converting it to?
I’m wanting to convert TRUEHD to WAV 32-bit Float. But if Audacity is automatically converting it to ,for example, WAV 24 bit upon import… then this is undesirable.
Hope someone can help! Thanks in advance!
That would have to be using the optional FFmpeg libraty. That format isn’t built into Audacity.
I could be wrong but as far as I know, FFmpeg can’t decode the lossless part so you’re probably getting the regular Dolby AC3 part. … It’s supposed to be compatible in case your player or player software doesn’t support the full lossless HD format. The lossless DTS formats use a similar “trick”. (You’ll never know by listening. 
)
Audacity normally converts everything to 32-bit floating point because processing is easier in floating point. And you should get the original sample rate.
Check your Quality Settings but it seems to convert to floating point no matter what.
Hi Doug! Thanks for helping me figure this out! I checked the Quality settings, it does say it has it at 32 bit float 
I have another question. So you’re saying that it’s possible that FFmpeg cannot detect TrueHD? So it’s converting it into an AC3 so that it can read it? If so, that would be undesirable for me as I want to convert the TRUEHD → WAV and not an AC3–>WAV.
Actually, double-checking (on Wikipedia :P) I was wrong!
TrueHD is Meridian Lossless (MLP). I’m pretty sure it’s decoded “completely” (or not at all).
It looks like it’s Dolby Digital Plus and DTS-HD that’s backward-compatible with the original decoders.
That’s great news! Thank you for checking that Doug!