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LPCM on ARC already supported?

  • July 6, 2020
  • 8 replies
  • 2064 views

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Hello, 

I’m confused. I was in the understanding LPCM is not (yet) supported by the Arc. Well, I just hooked everything up to my new LG CX (with eArc).  When playing a movie with Dolby TrueHD or  DTS(-HD MA) through Infuse on the Apple TV 4K which by default converts everything to LPCM, the “About My System”  page in the Sonos App shows the following.  It says “Dolby Multi-Channel PCM 5.1” and of course I can hear the sound as well. I’m just confused about the  “Dolby” part. Isn’t the whole purpose of LPCM that it isn’t Dolby or DTS. What am I missing?

 

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Best answer by Nicholas M

Dolby Multi-channel L-PCM isn’t the same thing as plain old multichannel-LPCM. It is the name for a Dolby MAT stream that contains multichannel l-pcm, which is fully supported.

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8 replies

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  • Prominent Collaborator I
  • July 6, 2020

That’s a new one. You get a software update the rest of us didn’t? :wink:


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  • Author
  • Enthusiast II
  • July 6, 2020

That’s a new one. You get a software update the rest of us didn’t? :wink:

Don’t think so. I’m at 12.01 for S2 controller. I believe that’s the latest.


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  • Prominent Collaborator I
  • July 6, 2020

That’s a new one. You get a software update the rest of us didn’t? :wink:

Don’t think so. I’m at 12.01 for S2 controller. I believe that’s the latest.

I was just teasing. I just haven’t seen this before so am as surprised as you. 


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  • Sonos Employee
  • Answer
  • July 6, 2020

Dolby Multi-channel L-PCM isn’t the same thing as plain old multichannel-LPCM. It is the name for a Dolby MAT stream that contains multichannel l-pcm, which is fully supported.


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  • Author
  • Enthusiast II
  • July 6, 2020

Dolby Multi-channel L-PCM isn’t the same thing as plain old multichannel-LPCM. It is the name for a Dolby MAT stream that contains multichannel l-pcm, which is fully supported.

Right, so quality is still less than for instance Dolby TrueHD / DTS-HD.MA am i right? Basically just Dolby Digital?


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  • Sonos Employee
  • July 6, 2020

Dolby Multi-channel L-PCM isn’t the same thing as plain old multichannel-LPCM. It is the name for a Dolby MAT stream that contains multichannel l-pcm, which is fully supported.

Right, so quality is still less than for instance Dolby TrueHD / DTS-HD.MA am i right? Basically just Dolby Digital?

Well the signal you are current getting is only 5.1 but it is uncompressed. Dolby MAT isn’t inherently less quality as a format and can support more than 5.1 inputs if the source provides them.


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  • Prominent Collaborator I
  • July 6, 2020

Dolby Multi-channel L-PCM isn’t the same thing as plain old multichannel-LPCM. It is the name for a Dolby MAT stream that contains multichannel l-pcm, which is fully supported.

Ah. Good to know! Learn something new every day. ;-) 


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  • Trending Lyricist III
  • September 9, 2020

I don’t understand: how come for you the Apple TV outputs Dolby MAT, and for mine (LG C9) it doesn't (apparently I need to wait for LPCM support from Arc)? All 5.1 content from Apple TV plays in Stereo 2.0, only Atmos content plays in Atmos…

Does your Apple TV play Atmos content as Atmos on Arc?