How do I make Dolby vision become active on 4 k uhd disc play back even when allow box has...

You need to purchase Dolby Access to enable Dolby Vision for media playback

There are no consumer panels that are 30-bit, 12-bit is basically the refuge of professional displays only

First we'd need to know the model of your display, and which discs you're trying to play

Make sure you have an Xbox Series X, Xbox One X or Xbox One S. In the back of the console, a sticker shows the model. If the adhesive is not, look for it below.
Important before turning the Xbox, make sure there is no album inside and then pour it.

Make sure you have a 4K TV. Check the box or television manual. Not all manufacturers use the same names. These are the denominations you have to look for:

Names for 4K
4K, 4K Ultra HD, UHD, UHD 4K, Suhd TV, Ultra HD, Ultra UDTV, 2160p
Resolutions or modes
3840 x 2160 to 24Hz, 50 Hz, 60Hz, 120 Hz

Names for HDR
HDR Premium, High dynamic range, HDR, UHD Color, Ultra HD Premium, Ultra HD Deep Color, HDR 10, Dolby Vision
In your Xbox, check the 4K and HDR functionalities of your TV. Press the buttonxbox  to open the guide, then go to profile and system> Configuration> General> screen and television options. Choose 4K television details.

For example, if you cannot select the 4K UHD resolution, 4K features are not admitted on the 4K TV Details, the 4K content does not reproduce or have problems with the quality of the video, try these suggestions.

Make sure Xbox automatically detects the TV. Go to Profile and System> Configuration> General> Screen and television options. In the advanced options column, choose fidelity and video envelope. In the screen column, make sure the automatic (recommended) detection is selected. The 4K feature is not available when HDMI or DVI are selected manually.

If strange colors are shown on the screen when reproducing HDR content, go to profile and system> Configuration> General> screen and television options. In the advanced options column, choose video modes and deactivate the allow HDR10 option.

If this does not solve the problem, it activates HDR10 again. Then, deactivate allow Dolby Vision and check if that solves the problem.
If an error appears when choosing 4K UHD in the screen settings, go to:
Solve a 4K UHD resolution error in Xbox

Hi I have a Xbox series x with a Dolby vision compatible tv also will the allow Dolby vision playback selected in settings on and it still only displays in HDR only when playing 4k blu rays ? I have set it 4k 60hz and the games display in Dolby vision plus streaming apps but not 4k disc playback! Is this correct that the xbox series can’t do this ?

Hi, my name is Marvina and I will be happy to help you.

I'm sorry you have this problem. Follow the instructions below for a solution.

These are the correct steps for configuration, verify them:

Things to keep in mind:
On Xbox Series X|S, Dolby Vision is available for gaming and media streaming apps.
On Xbox One X and Xbox One S, Dolby Vision is available only for media streaming applications.

The original Xbox One console does not support Dolby Vision.
Dolby Vision is not available for Blu-ray media playback.

To enable Dolby Vision, press the Xbox button  to open the guide, then go to Settings > General > TV & display options > Video modes > Allow Dolby Vision.

To enable Dolby Vision, press the Xbox button  to open the guide, then go to Settings > General > TV & display options > Video modes > Allow Dolby Vision for games.
To check if your display supports Dolby Vision, press the Xbox button  to open the guide, then go to Settings > General > TV & display options > 4K TV details.

For best results, we recommend a direct wired connection from your Xbox to the TV, such as an HDMI cable.
Note Check with your TV manufacturer for firmware updates and Dolby Vision game compatibility.

If your 4K@120Hz TV supports Dolby Vision games in 4K@60Hz but not 4K@120Hz, follow these instructions for Dolby games

Vision and contact the TV manufacturer.
Games in Dolby Vision:
Press the Xbox button  to open the guide and go to Settings > General > TV & display options.
Set Resolution to 4K.

Set Refresh Rate to 60Hz.
Play at 120 fps:
Press the Xbox button  to open the guide and go to Settings > General > TV & display options.
Set Resolution to 4K.

Set Refresh Rate to 120Hz.
If your TV has the latest firmware and you experience screen latency or input lag while playing games in Dolby Vision, disable Dolby Vision while playing games and contact the TV manufacturer.

To disable Dolby Vision, press the Xbox button  to open the guide, then go to Settings > General > TV & display options > Video modes > Allow Dolby Vision > Disable.

If your TV or monitor displays a blank screen after enabling Dolby Vision, disconnect and reconnect the HDMI cable. If you still see a blank screen, restart your Xbox console:
Press and hold the Xbox  button on your controller.
Select Turn off console or Restart console > Restart.

Information source (credits):
https://support.xbox.com/help/hardw...o enable Dolby Vision, press,de video > Allow %20Dolby%20Vision.

I hope I can help you solve it.

Best regards,
Marvina.

Of course the Blu-Ray disks I'm using are UHD and have Dolby Vision.

Dolby Vision is enabled on Xbox One X settings, TV HDMI ports are in Enhanced mode (4:4:4 4K/UHD HDR 60Hz), and the TV test (that can be found inside Xbox menu) returns all green ticks for my Xbox-to-TV connection.

As said, Dolby Vision works with all streaming apps... but not when playing Blu-Ray UHD Dolby Vision disks.