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How does AppleTV 4K check Dolby Vision via HDMI

BJMRamage

macrumors 68030
Original poster
Oct 2, 2007
2,537
935
Hello,

I have had issues with my AppleTV/soundbar/tv connections for a while. When they work great they are awesome but occasionally i get blackouts.

I have swapped cables many times and things start out fine then get worse.

I replaced my Monoprice 2.0 High Speed Certified Cables to 2.1 Ultra High Speed cables and everything seemed great...then a few days later the TV screen blacked out and back and it seemed to do that a lot going into Settings. I turned off Dolby Vision and think I also changed the MATCH Content Range and Refresh Rate. I then opted to MATCH RANGE, and would see my TV say it was now showing HDR10.

Today I tried to enable Dolby Vision and this time around it said the cable was not high speed. so it switched me off DV.

SO, how does the AppleTV check the HDMI cable?
does it send info and then receive back info? I have my cables plugged into a sounder first and then TV, does it need to go through BOTH to the TV and back or would it just do a bounce check to the soundbar and back?

I've often wondered if the soundbar is the issue even though it says it can pass Dolby Vision, wondering if the Audio is also set to Atmos it cant do it all. Maybe the soundbar/HDMI inputs are broken or not working correctly

Thanks in advance

*I know a soundbar is not GREAT sound-and Atmos is 'junk' on a soundbar setup. I also do not have an OLED 4K. I am stepping up from a 1080, 2.1 sound so just wanted more and while everything worked perfectly with 1080 my 4K setup is a very fragile, finicky mess with the slightest change for some reason and I loose sound or picture etc. I moved during peak Pandemic so I hooked everything up myself thinking it is cables/conecction. I have done this before no need to have someone come out to install anything if any company would even do that at the time. I have a Vizio M series and Vizio sound bar and Apple TV 4K...all purchased via Costco.
 

musicman0725

macrumors regular
Oct 25, 2007
127
10
Hello,

I have had issues with my AppleTV/soundbar/tv connections for a while. When they work great they are awesome but occasionally i get blackouts.

I have swapped cables many times and things start out fine then get worse.

I replaced my Monoprice 2.0 High Speed Certified Cables to 2.1 Ultra High Speed cables and everything seemed great...then a few days later the TV screen blacked out and back and it seemed to do that a lot going into Settings. I turned off Dolby Vision and think I also changed the MATCH Content Range and Refresh Rate. I then opted to MATCH RANGE, and would see my TV say it was now showing HDR10.

Today I tried to enable Dolby Vision and this time around it said the cable was not high speed. so it switched me off DV.

SO, how does the AppleTV check the HDMI cable?
does it send info and then receive back info? I have my cables plugged into a sounder first and then TV, does it need to go through BOTH to the TV and back or would it just do a bounce check to the soundbar and back?

I've often wondered if the soundbar is the issue even though it says it can pass Dolby Vision, wondering if the Audio is also set to Atmos it cant do it all. Maybe the soundbar/HDMI inputs are broken or not working correctly

Thanks in advance

*I know a soundbar is not GREAT sound-and Atmos is 'junk' on a soundbar setup. I also do not have an OLED 4K. I am stepping up from a 1080, 2.1 sound so just wanted more and while everything worked perfectly with 1080 my 4K setup is a very fragile, finicky mess with the slightest change for some reason and I loose sound or picture etc. I moved during peak Pandemic so I hooked everything up myself thinking it is cables/conecction. I have done this before no need to have someone come out to install anything if any company would even do that at the time. I have a Vizio M series and Vizio sound bar and Apple TV 4K...all purchased via Costco.

So I think you might be on to something with the sound bar. My receiver has a setting (and if you do a google search I think the Vizio sound bar may as well) for hdmi where you need to have the signal format set to enhanced to open the hdmi port up for full bandwidth. Make sure that this is enabled. Also, you will want match range and match frame rate enabled. I believe most DV content on the ATV4K requires a lower frame rate so it falls back to HDR10 if you only have match range enabled.
 
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JasonHB

macrumors 6502
Jul 20, 2010
329
226
Warwickshire, UK
Have you tried the Apple TV directly to the TV??

Have you checked the TV specs? Not all HDMI ports on some TV’s support the relevant standards for 4K etc.

Jason
 
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Realityck

macrumors 6502a
Nov 9, 2015
884
807
Silicon Valley, CA
SO, how does the AppleTV check the HDMI cable? does it send info and then receive back info? I have my cables plugged into a sounder first and then TV, does it need to go through BOTH to the TV and back or would it just do a bounce check to the soundbar and back?

I've often wondered if the soundbar is the issue even though it says it can pass Dolby Vision, wondering if the Audio is also set to Atmos it cant do it all. Maybe the soundbar/HDMI inputs are broken or not working correctly
You need to power up everything in reverse order. Not all at once Vizio M Display -> Vizio soundBar -> Apple TV 4K.
In order to support Dolby Vision the source needs to be able to see the TV device capability to know that it meets HDMI 2.0/HDCP 2.2 and it can send a 4K HDR (DV) to it. The soundBar being a HDMI repeater must be able to pass that meeting the same HDMI 2.0/HDCP 2.2 spec for it to work in a single HDMI chain. Otherwise you would use a split video (dual HDMI hookup)
 
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BJMRamage

macrumors 68030
Original poster
Oct 2, 2007
2,537
935
Have you tried the Apple TV directly to the TV??

Have you checked the TV specs? Not all HDMI ports on some TV’s support the relevant standards for 4K etc.

Jason

I did a few months back and all seemed fine. But then the Atmos won’t get sent so I wasn’t sure if DV and DA together was an issue somewhere.
 

BJMRamage

macrumors 68030
Original poster
Oct 2, 2007
2,537
935
You need to power up everything in reverse order. Not all at once Vizio M Display -> Vizio soundBar -> Apple TV 4K.
In order to support Dolby Vision the source needs to be able to see the TV device capability to know that it meets HDMI 2.0/HDCP 2.2 and it can send a 4K HDR (DV) to it. The soundBar being a HDMI repeater must be able to pass that meeting the same HDMI 2.0/HDCP 2.2 spec for it to work in a single HDMI chain. Otherwise you would use a split video (dual HDMI hookup)

does this mean unplug and replay to power on?

or just unplug hdmi cablea and replay?

orI need to turn on TV first then sound bar. Then the AppleTV and never turn AppleTV on before the TV?

thanks for the tip.
 

Realityck

macrumors 6502a
Nov 9, 2015
884
807
Silicon Valley, CA
does this mean unplug and replay to power on?

or just unplug hdmi cablea and replay?

orI need to turn on TV first then sound bar. Then the AppleTV and never turn AppleTV on before the TV?

thanks for the tip.
Turn the TV on, wait a couple of seconds, turn on soundBar, wait a couple of seconds, turn the Apple TV on. You never disconnect or reconnect HDMI cables with devices powered. Once you have your device chain connected, it’s rare you have to touch them. :)
 
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BJMRamage

macrumors 68030
Original poster
Oct 2, 2007
2,537
935
^ Thank you

This morning I changed the MATCH to refresh rate as well and see Dolby Vision icon on TV again. seemed fine for the brief period I was using it. I made sure to have the TV going for a while ahead of time before switching to AppleTV.

I'll keep tabs on it for the next week or so.
 
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