Video Latency Engineering: Glass-to-Glass Measurements & Penetration Limits

The video link is a pilot's eyes. Glass-to-glass latency represents the total delay from the camera sensor capturing a frame to the goggle display illuminating.

1.1 Analog Zero-Latency

Analog video systems stream raw video lines as they are read from the sensor, bypassing digital encoding. Glass-to-glass latency is constant ($< 10\text{ ms}$), providing unmatched feedback for racing.

Digital FPV systems convert the analog sensor data into compressed digital streams (H.264/H.265) before transmitting.

2.1 HDZero (Uncompressed Digital)

HDZero uses uncompressed digital transmission. Like analog, it transmits line-by-line. Latency is constant and fixed at $\approx 14-16\text{ ms}$ regardless of range.

2.2 DJI & Walksnail (Compressed Digital)

DJI and Walksnail compress frames to achieve high resolution (1080p).

• Variable Latency: Total delay varies ($25-45\text{ ms}$) depending on signal quality.
• Buffer Delay: Bad RF conditions force packet retransmissions, increasing buffer delays and causing frame drops.

Digital systems rely on error correction coding to survive signal reflections. If RF attenuation exceeds the error correction threshold, the stream will instantly pixelate or freeze.