Introduction

Difficulty Easy Time Required < 5 minutes

The HD Multi SeaCam is often used in applications where an operator is using the streamed video as feedback in a remote task. In these situations, minimizing the end-to-end latency improves the operator efficiency and is critical to successful remote control. This guide covers different methods that will improve and minimize the visual latency in the HD Multi SeaCam.

Sources of Latency:

As an Ethernet connected device, the IP versions of the HD Multi SeaCam rely on a physical network to transfer data from the camera to a display. Other equipment attached to this same network share the limited bandwidth of the system and can slow down the effective data transfer rate. Also, in order to handle the bursts of data transmitted over the network both the camera and the receiving device, whether that is a computer application or a dedicated hardware decoder, use buffering to provide a smooth playback experience. Larger buffers introduce longer delays and add latency but they are needed in busy networks or in situations where the available network bandwidth is low or inconsistent.

Best Practices:

• Maximize the availability of the network for critical cameras. This can be achieved by putting the camera on a dedicated network free from other devices competing for bandwidth or if available, by prioritizing the Ethernet traffic on the camera's port.
• Minimize the receive stream buffer size. On the decoder end of the system, size the receive buffer to the minimum required for consistent and reliable playback of the video. This may be a parameter that needs to be evaluated and set in-situ as a part of the commissioning process for the camera and video system.

VLC - Recommended Stream Settings

By default VLC will decode a network video stream with more than a second of delay due to the size of the input stream buffer. Changing the buffer settings in the stream setup or in the VLC Preferences can reduce the latency to around 450ms at 1080p/30.

	Open the VLC Preferences dialog box under Tools → Preferences Click on the Audio tab and deselect "Enable audio" Click on the Input/Codecs tab and scroll to the bottom to select "Lowest latency" from the Default caching policy drop box
	In the Open Media dialog box under Media → Open Network Stream, paste the RTSP stream URL for the camera and click the check box for "Show more options" The Caching parameter will be set to 333ms but on a good network this can be reduced to 100ms without creating problems with the video feed. If there are dropped frames or image artifacts, this caching parameter may need to be adjusted.

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