Seconds That Matter: When Real-Time Viewing Isn’t Real-Time

Did you know that some CCTV systems can exhibit a live view delay of up to three seconds? That’s three seconds where a critical incident could unfold unseen, three seconds that could mean the difference between prevention and reaction. When we talk about live view delay, or latency, we're referring to the time difference between an action taking place in front of a camera and the moment you see that same action on a monitor. In a world where real-time information is more crucial than ever, this seemingly brief gap can have profound implications for security and surveillance. With potential breaches, accidents, and criminal activity occurring in the blink of an eye, those three seconds can be the difference between effective intervention and a missed opportunity. This article will dissect the causes of this often-overlooked issue, explore which systems offer the lowest latency, examine real-world applications where minimal delay is paramount, and provide practical strategies to reduce lag in your CCTV setup. 

In IP-based CCTV systems, network congestion is a common restriction. Bandwidth limitations, particularly during peak usage periods, can significantly impede the flow of video data. Imagine a highway during rush hour; the same principle applies to your network. When multiple devices compete for bandwidth, the video stream can become bottlenecked, leading to delays. Routers, switches, and bridges are all points of contention, a slow or overloaded router, or a network switch with insufficient capacity, can introduce significant latency. Similarly, a poor internet connection, and remote viewing scenarios, will significantly increase delays. 

The processing power of the camera, NVR/DVR (Network/Digital Video Recorder), and display devices also impacts latency. Older or less powerful hardware, lacking the necessary processing capacity, will struggle to handle the demands of real-time video processing. This can lead to significant delays, especially with high-resolution video streams. 

The process of encoding and decoding video is another major source of latency. Before a camera's video stream can be displayed, it must be compressed (encoded) to reduce its file size, then decompressed (decoded) for viewing. Different codecs, such as H.264 and H.265, employ varying compression algorithms. H.265, offers superior compression efficiency. The processing power of both the camera and the viewing device is critical. If either lacks the necessary horsepower, the encoding and decoding process can become a bottleneck, resulting in noticeable lag. 

The processes that take place from video recording to being displayed on screen also affects the amount of delay. The more complex the process, the longer the delay.  

The analogue CCTV camera uses an image sensor (typically a CCD or CMOS sensor) to capture the scene. This sensor converts the light entering the camera lens into an electrical signal. However, this signal is an analogue wave form. The analogue video signal is then transmitted through a coaxial cable. This cable carries the raw, unprocessed video signal directly to the recording device, which is usually a Digital Video Recorder (DVR).  

 To display the video on a monitor, the video signal is sent straight to the monitor with no need to encode or decode it first which is why it’s so fast. Encoding and decoding only happens when the video data need to be saved to the hard drive and viewed later through playback.   

The IP camera uses an image sensor (CMOS) to capture the scene. Crucially, the IP camera itself digitises the captured image right away. It converts the light into digital data. This digital data is then processed by the camera's internal processor. This is where encoding happens. The IP camera's processor compresses the digital video data using a codec. This encoded video is then packaged into data packets, ready for transmission over the network. 

The IP camera transmits the data packets over an Ethernet cable (CAT5/CAT6). These packets travel through the network infrastructure, which may include switches and routers, depending on the network setup. The packets travel to the NVR. The NVR will decode the video stream. This process reverses the encoding, restoring the video data to its original format. The decoded video data is then sent to the monitor. The monitor displays the video image. 

A Wi-Fi camera uses an image sensor (CMOS) to capture the scene. The camera's internal processor digitises the captured image, converting it into digital data. The camera's processor compresses the digital video data using a codec This encoded video is then packaged into data packets, ready for wireless transmission. The camera's Wi-Fi radio sends the data packets to a wireless router. The strength and stability of the Wi-Fi signal are crucial factors in determining latency. Obstacles, distance, and interference can affect signal quality. 

The wireless router receives the data packets from the camera. The router then forwards the data packets to a cloud server or viewing device over the internet. If the video is sent directly to a viewing device, the device's software decodes the video stream, restoring the video data to its original format. The decoded video data is then sent to the display screen of the viewing device.   

One of the most common industries that we see in need of minimal latency is Stage work and Film sets: For stage technicians during live performances, or on busy film sets, real-time monitoring is vital. They need to see exactly what is happening on stage or set, in real time, to ensure the safety of performers and crew. Any lag in the video feed can lead to missing structural weak points, technical mishaps, and even dangerous situations. Real-time monitoring ensures that everyone involved can react to events as they happen, maintaining control and ensuring safety. 

To minimise latency in your CCTV system, start with high-quality components. Invest in cameras and recorders with enough processing power to balance resolution and frame rate with ease. Use quality RG59/ RG6 coaxial cables as analogue systems have the shortest delay (almost none). Utilise efficient codecs like H.265 and keep device firmware and software updated. Ensure your display device has minimal processing delay and are all connected via cable. By following these steps, you can significantly reduce latency and improve surveillance effectiveness. 

As we've explored, latency in CCTV systems, the delay between a live event and its display, arises from a complex interplay of factors including network congestion, processing power, and encoding/decoding processes. Whether you're using analogue, IP, or Wi-Fi systems, minimising these makes all the difference for effective surveillance. By investing in quality hardware, optimising network configurations, and utilising efficient codecs, you can significantly reduce latency and get the most out of your real-time monitoring. 

For industries where every second counts, minimal latency is not just a preference, it's a necessity. If your operations demand the absolute lowest delay in your CCTV system, don't hesitate to contact CCTV Outlet. Our experts have also curated the “Stage Production” bundle that after plenty of research, has practically zero latency with smooth and clear imagery.