Why does the picture from my cable or satellite box look bad on my Roku TV™?
If your Roku TV supports 8K Ultra HD, it has two different types of HDMI® inputs. When a device that outputs an interlaced video signal is connected to the wrong type of input, you may see the following on-screen message.
This article provides more details about interlaced video and your 8K Roku TV and explains what to do to get the best picture from your cable or satellite set-top box.
What is interlaced video?
Before the days of 4K and 8K Ultra High Definition, video resolutions were expressed as the vertical number of pixels on your TV screen. Traditionally, this numerical value was accompanied by an 'i' to indicate the video signal was interlaced (e.g., 480i, 576i, or 1080i), or a 'p' to indicate it was progressive (e.g., 480p, 576p, 720p, 1080p).
- Interlaced - An interlaced signal sends only half of the information captured in each video frame at a time, delivering the odd pixel lines first (1, 3, 5...) followed by the even pixel lines (2, 4, 6...). This uses less bandwidth but requires your TV to combine these "fields" using a process called de-interlacing to draw the complete frame. This happens fast enough that your eyes see the entire frame, but you may notice flickering or motion artifacts such as jagged edges, especially in fast-moving scenes.
Progressive - A progressive signal sends the full video frame at one time delivering all the pixel lines to fill the screen. This requires more bandwidth but appears smoother and more realistic and reduces flicker and artifacts.
Devices using the latest technologies use a progressive signal, but many older devices like cable and satellite boxes may still use an interlaced signal.
Which HDMI input should I use for an interlaced signal?
Your 8K Roku TV has two specialized HDMI inputs designed for optimal playback of 8K content and the low-latency processing required for high-end game consoles. It also has two standard HDMI inputs that can do proper de-interlacing. To get the best picture form any device that uses an interlaced signal, use HDMI 3 or HDMI 4.
Inputs optimized for 8K playback and low-latency gaming devices:
- HDMI 1
- HDMI 2
Inputs with de-interlacing to properly process interlaced signals:
- HDMI 3
- HDMI 4