In an IP-based video system, audio can be transmitted alongside video over the same network, allowing for integrated audio-video surveillance. This enables the simultaneous monitoring of both audio and visual data, enhancing situational awareness. Additionally, some Axis video encoders support audio functionality with analog cameras, allowing these older devices to be integrated into modern IP-based systems and take advantage of audio capabilities. Axis documentation highlights these features, emphasizing the seamless integration of audio and video in IP surveillance solutions and the extended functionality provided by video encoders.

H).264 compression uses I-frames (intra-coded frames) as reference points, with P-frames (predictive frames) and B-frames (bi-directional frames) encoding only the changes from the previous frames. If a video contained no I-frames, there would be no reference frame for decoding, resulting in an inability to display any image. This would theoretically result in a black image being visible during the whole video. Therefore, the correct answer is B. For more detailed information, refer to Axis Communications' technical notes on video compression.

"When a lens intended for a larger sensor is used on a smaller sensor camera, the projected image circle does not fully cover the sensor area, causing vignetting or black corners in the image."
- Axis Lens Guide White Paper
"Black corners or vignetting often result from a mismatch between lens and sensor size."
- Axis Communications Academy, Network Video Fundamentals, 2022
References:
Axis Lens Guide White Paper
Axis Communications Academy, Network Video Fundamentals, 2022 (p. 34)

The ONVIF (Open Network Video Interface Forum) standard provides several benefits to end users. One key benefit is that it helps create future-proof systems and more secure investments by ensuring interoperability between different manufacturers' devices, which protects against obsolescence. Additionally, ONVIF increases flexibility and offers greater freedom of choice, allowing users to mix and match devices from different vendors, thereby tailoring their security systems to specific needs without being locked into a single manufacturer's ecosystem.
References: Axis Communications ONVIF Conformance Documentation and ONVIF.org Benefits of ONVIF.

In a network surveillance installation, the primary purpose of a switch is to forward the video stream to the correct receiver within a network. This functionality ensures that the video data captured by cameras is correctly directed to the appropriate storage device, monitoring station, or viewing client within the local network. Switches operate at the data link layer (Layer 2) of the OSI model and utilize MAC addresses to ensure that data packets reach their intended destination efficiently.