Video Systems and Display Technologies
What this domain tests
This domain tests resolution, aspect ratio, refresh rate, pixel clock and bandwidth, color spaces, chroma subsampling, and the practical differences among LCD, OLED, and LED-wall displays. Expect items on projector throw, display brightness, and signal compatibility.
Core rules
- Resolution is pixel count; 1920 × 1080 is 16:9, while 1920 × 1200 is 16:10. Aspect ratio affects how content is scaled or letterboxed.
- Uncompressed video bandwidth scales with pixels × frame rate × bits per pixel; chroma subsampling reduces bandwidth by storing less color detail.
- Throw ratio = throw distance / screen width. It is not based on screen diagonal.
- LCD displays require a backlight and can show motion blur and limited contrast; OLED pixels are emissive and can achieve deep blacks; LED walls use discrete LED modules and pixel pitch determines minimum viewing distance.
- Brightness for projection is measured in lumens; display brightness is measured in nits (cd/m²). Ambient light and screen gain affect perceived contrast.
Worked example
A projector has a throw ratio of 1.5:1 and must fill a 3.0 m wide screen. Find the required throw distance.
- Throw ratio = distance / width.
- Distance = ratio × width = 1.5 × 3.0 = 4.5 m. Reasoning: the 3.0 m dimension is width, not diagonal. If only the diagonal were given, you would first convert to width using the aspect ratio.
Traps
- Using diagonal instead of width in throw-ratio calculations.
- Comparing projector lumens directly with display nits without accounting for screen area and gain.
- Assuming all 4K signals are equal; chroma subsampling, bit depth, and frame rate change bandwidth.
- Ignoring EDID and HDCP when a display does not accept the source format.
- Forgetting that LED wall pixel pitch sets a practical minimum viewing distance.