Atmos to LPCM issue


Novice Member
I would be curious to see if anyone has thoughts on this issue.

Apple TV 4k
Ezcoo Mx42 Splitter
LG OLED E9 (splitter output set to 4k)
Meridian HD621 (HDMI 1.4 device that takes 5.1 audio from HDMI and splits it to 3 Spdif outs that go the audio processor (its known as AES3)

I am using a HDMI Matrix switch to send 4k from my Apple TV to a 4k OLED and 1080 to the HD621.

Everything works great with non Atmos titles. I get 4k DolbyVison and LPCM out of my Meridian system. Looks and sounds great.

However, when a show has Atmos sound, if I send 4k to my screen, the sound is incorrect. The dialogue is missing and I hear music coming out of the center channel, which I think is the surround channel. The display on my surround processor shows 2 channel PCM. It should read 6 channel PCM,
Of course I can solve this by allowing the Apple TV to change the format to DD 5.1 but I think it doesn't sound as good.

One thought is that since the HD621 is only 1.4 Hdmi spec and does not support HDCP 2.0 and above, the apple tv is forced to send 2 channel PCM.

So I am wondering what options I have... I am trying to get the least expensive option.

1. See if I could get a firmware fix from the HDMI Switch manufacturer. I would need to know what to ask for in the simples terms.

2. Add some type HDCP conversion box that presents HDCP 2 to the ATV and HDCP 1? to the audio processor.
3. Use the more costly HDfury Vertex2
4. Use the even more costly Meridian UHD 722 (4k version of HD621 that I have now)

If I set the HDMI switch to downscale the 4k to 1080 everything works fine.

If anyone is interested the switch I am using is an Ezcoo MX42HA.
Ian S

Joe Fernand

Distinguished Member
AVForums Sponsor
Not sure I follow what you are asking for!

You want to send Atmos to a Processor which does not support Atmos and you notice compressed 5.1 is not as good as uncompressed 5.1!



Novice Member
Sorry if it wasn't clear. I want LPCM from the ATV. (atv is set to auto/atmos is set to off)
If the program is listed as Dolby Vision and Atmos in the title description, for example on ATV+ the show "Ted Lasso", With ATV set to auto, my processor shows 2 channel PCM and the channel assignments are not correct, in fact some channels are missing.

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