Latency Comparison: LIQUID vs AirPlay

METHOD

Hardware

Software

  • Astropad Studio 3.2 (Same liquid engine as Luna)
    • Astropad Studio was running at a zoom of 100%, non-retina
  • MacOS 10.14.5
    • AirPlay version unknown as it is built into MacOS

Websites Used

LATENCY TEST

A latency test measures a difference in time. For this specific test, an image is generated on the main display and mirrored to a wireless display. The image displayed on the main display is a web application that changes roughly every millisecond.

Due to various delay inducing components (Wi-Fi interferences, processing time, etc), the number displayed on the wireless display will lag slightly behind the main display. A rough latency estimate can be found by calculating the difference between these two numbers.

Lower latency results in faster feedback to a user. Low latency is critical for drawing applications as it determines how realistic the application feels when compared to traditional media.

The standard measurement unit for latency is milliseconds (abbreviated ms). There are 1000 ms in one second. Microsoft has done extensive research in the area of drawing latency has found that humans can perceive drawing latencies as low as 1ms!

 

Liquid (3.2)

AirPlay (10.14.5)

Average (ms)

16.27

93.24

Median (ms)

17

99

Standard Deviation

2.52

8.28

Max (ms)

19

104

Min (ms)

0

82

Full data sets: 

FRAME SKIPPING TEST

Most displays on the market target 60 frames per seconds (abbreviated FPS). For a display to hit 60 FPS, it must process and display a single frame in under 16.66 ms. 

The more frames a display can generate per second, the smoother the images on that display feel. If a display drops or skips too many frames the performance can feel jerky or jumpy. LIQUID targets 60 FPS to get the best display performance.

The following videos demonstrate testing for frame skipping. The MacBook Pro is the source. In the frame skipping test every box should be lit up at the same time as the main display. If the box does not light up, the frame was skipped.