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confused with audio formats true hd etc


Established Member
the film 21 works great but the truehd sound track is playing as PCM on my surround sound amp. I have the onkyo 864 (I think that's the model number) which doesn't support truehd or dts-hd.

it seems the only english soundtrack (apart from descriptive) on the disk is truehd and from the original this plays in PCM too.

I was under the impression that hd audio formats downsampled to dd5.1 or dts?

Is this not the case or is it because I am playing it through my computer connected by coax?

If I was to use my ps3 and connect via hdmi will I get DD5.1 (as my amp doesn't support truehd)

The sound quality of PCM is crap. There is no sound from the rear speakers and it sounds like plain stereo sound. Not what I want to listed from HD



Established Member
having just read about the HD audio formats myself. It sounds like your trueHD is being converted to PCM because essentually that is what it is but coax does not support multi channel for PCM so it is being downgraded to 2 channel.

Found this useful only 10 minutes ago as I am new to the different HD formats as well.

High-Def FAQ: Blu-ray and HD DVD Audio Explained | High-Def Digest


Prominent Member
If you've got it connected via optical, then it is likely that you are only getting a downmixed stereo feed. If you use HDMI, and ask the PS3 to output the sound as LPCM, then provided your amp can accept an LPCM feed (and a two years old model should do), you will get a full HD soundtrack in 5.1 (or 7.1, depending on the film and your set up).

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