Mi Laser Projector 150" PCM - 5.1 DTS issue


PavelOl

Members
Apr 2, 2021
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Hello everyone,
i have a setup: UST projector connected by optical cable directly with the receiver Pioneer SC1223.
Output on the projector is set to SPdif and Raw.
When i switch the receiver to the projector audio channel - receiver shows PCM and i get only stereo sound.
Tried factory reset and different players already. It seems that there is a codec inside the projector which outputs only pcm, no matter of the options i choose in the menu.
Anybody has the issue with 5.1 or know how to access the codecs of the projector and check it there?

Thanks!
 
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Hello Everyone,

I have the same issue. I bought Mi 4K Laser Projector 150''

I have Pioneer VSX 921. Before the projector I have had a Samsung TV and it worked. All connections was setup the same.
I connected the projector through HDMI3 (arc) to HDMI out (arc) of the Pioneer Receiver.
My xbox and apple tv connected to the HDMI 1 and HDMI 2 of the MI Projector.
I setup in Audio settings - HDMI and tried both (PCM or Auto) I can hear the stereo sound normally but all Dolby Digital or DTS signals do not seen at receiver. Normally it detects the ac3 signal and enable DD or DTS mode.
I also tried to connect SPDIF with the same result, I can hear the stereo sound but it does not decodes to DD or DTS on Receiver.

When I use Apple TV the Dolby Digital sound decoded on Receiver. So the problem is not in the cable or Receiver but in the settings of the Projector.

I have tried VLC player, MX player etc. with AC3 pass through or without and the results are the same - only stereo sound.

So I think that there are some hidden settings on the projector itself on how it sends the PCM signal.

Please advise.

Thank you in Advance.
 
Hi! I managed to make it work.
I bought an optical cable and set the sound output to Spdif. Then i made a factory reset of the receiver and assigned the optical channel to TV input with DTS enabled .it works. I assume the problem is the hdmi arc. It just doesnt work this way.
 
Hi thanks for update,
Unfortunately this not work for me, I already have an SPDIF and I tried both.
As I said before the sound goes through hdmi or through spdif but it doesnt sends a dolby digital or do not provide ac3 pass-through. I tried different apps and hear only the stereo.
Although, if I use AppleTV connected to the Projector the Receiver detects DD and plays as intended.

@PavelOl May I ask you please what settings you use in Audio of the Projector...
 
when you use SPDIF do you actually connect projector with the receiver by Optical cable? it is important. in my case hdmi never worked.
also try reset your receiver and assign the optical cable to the TV input of receiver (and choose the audio output there. in my case there was Stereo, but possibility to choose DTS, which i did and it finally worked)
 
Hi,

yep I connected HDMI 3(arc) on Projector to TVout(arc) HDMI on my Receiver.
I also connected SPDIF from Projector to Receiver TV input.

I have stereo sounds from both sources. Just DD or DTS not coming or my Receiver do not understand the signal from Projector.
In Android TV on Projector Audio settings I tried PCM or Auto, doesn't help.
On my Receiver I cannot choose which signal to receive, it detects PCM or DD or DTS automatically and begin to decode.

It works normally with PC, Xbox, Samsung TV, Apple TV.

I also found old Thread about Mi TV Box with the same problem as I have:
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He was able to solve it by enabling pass-through (what I already did) in VLC but he can decode only DTS signal not DD.
I will try do find the Movie with DTS to check.
 
I also found interesting article.
PCM

PCM is an uncompressed audio format, which means it will theoretically have the best overall sound quality, as no information has been removed to facilitate transmitting the signal. PCM is sent unencoded by the source, meaning the full, unpacked ‘instructions’ for what sounds to play are sent directly from the source to receiver, and then on to the speakers.

Unfortunately, this makes for a signal that is more difficult to transmit. No TV seems to be able to pass a 5.1 PCM signal through to a sound system, so sending a PCM signal to or from a TV will downgrade the signal to 2.1 (two speakers + one subwoofer), thus eliminating the extra channels necessary for surround sound.

PCM 5.1 can work with a receiver that supports the format, so if you want uncompressed sound, you’ll need to forego passing the audio through your TV, and instead output the sound directly from the source (one that outputs PCM 5.1) to the receiver. Note that only HDMI can transmit a 5.1 PCM signal. Digital optical is only capable of transmitting a 2.1 or 2.0 PCM signal.
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So my guess that MI Laser cannot go with full 5.1 PCM. But why it doesnt pass through in Auto...
 
Hi,

yep I connected HDMI 3(arc) on Projector to TVout(arc) HDMI on my Receiver.
I also connected SPDIF from Projector to Receiver TV input.

I have stereo sounds from both sources. Just DD or DTS not coming or my Receiver do not understand the signal from Projector.
In Android TV on Projector Audio settings I tried PCM or Auto, doesn't help.
On my Receiver I cannot choose which signal to receive, it detects PCM or DD or DTS automatically and begin to decode.

It works normally with PC, Xbox, Samsung TV, Apple TV.

I also found old Thread about Mi TV Box with the same problem as I have:
To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

He was able to solve it by enabling pass-through (what I already did) in VLC but he can decode only DTS signal not DD.
I will try do find the Movie with DTS to check.
i tried VLC- no luck in my case, so i use Plex. same in my case. receiver detects PCM or DTS and begins to decode, but somehow all appeared in Stereo only, until i managed to assign the DTS by default for audio input from projector
 
Im continue testing and found out that E-AC3 audio going through HDMI-ARC from Projector to my Receiver from any source (VLC etc.) are decoded normally. So I presume that AC3 and DTS is somehow captured by Projector and do not passing through even if set so in Settings...
 
Resurrecting this to ask, did anyone solve it? I have my AppleTV connected to the projector, and use optical out from the projector to the dolby 5.1 system, but only get 2.1! any help is appreciated. Thanks!
 
Resurrecting back, I have the same issue with an old DTS yamaha receiver connected via optic SPDIF. I just get 2 channels, I'm blaming the receiver as it is not DTS-HD compatible. But it would be great to confirm if anyone have been able to get more than 2 channels from the digital out.