How to check whether a 4K stream is playing in 4K
Compare the title format, device path and playback conditions before changing network hardware.
IPTVBlogs editorial desk · 
A television can report a 4K HDMI input while the app is playing a lower-resolution stream. Start by verifying the plan, the exact title and the streaming device. Use the app’s own playback information if it exposes it, rather than treating the television’s HDMI resolution as a stream measurement.
Test one title on the same device
Select a title the service labels 4K on your account. Start the film and let playback settle before comparing picture quality. Keep the device, HDMI path and network constant while you test a second 4K title. If one title behaves differently, review that listing before changing your television or router.
Check the components in order
Compare the app’s supported device list with your model. If you are using a streaming box through a receiver, consult each component's documentation and use the supported HDMI input. If format changes with network conditions, compare the same title on a wired connection where available. Record what you observed from the app and what came from the TV’s input panel.