pcm

[sewerdog]

some of my blu-rays say PCM 5.1 and Dolby 5.1 audio what is the difference in sound and which is the best to play?

[HiDef-Crazy]

PCM is lossless audio true to the master has a lot higher bit rate and sounds amazing compared to Dolby 5.1 PCM is the better choice if your receiver is capable of decoding it.

[sewerdog]

i have an older onkyo unit tx-sr302 that does pcm while watching the first pirates i was going from pcm back to dolby the dolby sounded louder than the pcm

[BStecke]

So . . . turn it up. Louder doesn't equal better.

[BIslander]

PCM is the digital audio format used to record movie soundtracks and CDs. Multichannel PCM files are quite large, too large to fit on films, CDs, or DVDs. DD 5.1 is a type of zip file used to compress the PCM so that it will fit on various media. A DD 5.1 file must be decoded (unzipped back into PCM) before it can be played.

Dolby uses so much compression that some of the original PCM removed during encoding cannot be restored during decoding. It's called a "lossy" codec because some of the audio data is lost. PCM is the original soundtrack. A decoded DD 5.1 track is something less than the original.

TrueHD is another type of zip file developed by Dolby. It uses less compression than DD 5.1 and all of the data removed during encoding is restored during decoding. TrueHD is a "lossless" codec because none of the data is lost. PCM is the original soundtrack. A decoded TrueHD track produces an exact copy of the original.

Originally Posted by HiDef-Crazy

PCM is the better choice if your receiver is capable of decoding it.

There's no decoding needed for PCM. All consumer electronics equipment can play PCM. It's the foundation of pretty much all digital audio.

[HiDef-Crazy]

Are you using an optical cable or does your receiver have HDMI? If using an optical cable you will only get 2.0 PCM not 5.1 the optical can't handle the extra bit rate. There are others on here that can probably explain it better than I can.

Like BIslander Thanks

[HiDef-Crazy]

There's no decoding needed for PCM. All consumer electronics equipment can play PCM. It's the foundation of pretty much all digital audio.[/QUOTE]

Thanks I forgot about that. Sorry

[sewerdog]

coaxial receiver has no hdmi

[BIslander]

Originally Posted by sewerdog

coaxial receiver has no hdmi

Over coax, DD 5.1 will give you discrete 5.1. But, PCM is limited to a stereo downmix. It's high res audio, but just two channels.

[Big Daddy]

Originally Posted by sewerdog

some of my blu-rays say PCM 5.1 and Dolby 5.1 audio what is the difference in sound and which is the best to play?

Please read A Guide to Home Theater Audio Codecs. It has a sticky in the Audio sections. All the HT audio codecs are discussed there.