In the world of CCTV surveillance, capturing high-quality footage is only part of the equation. Equally important is how that footage is compressed, stored, and retrieved efficiently. As surveillance systems have evolved—offering higher resolutions, longer recording times, and smarter analytics—the need for efficient video compression has become critical. This article explores the most common video compression formats used in DVRs, how they work, and what the future holds.
Every camera connected to a Digital Video Recorder (DVR) generates a continuous stream of visual data. Without compression, storing even a few days' worth of high-resolution footage would require massive amounts of disk space. Video compression reduces file size by removing redundant or nonessential data—allowing systems to store more footage, use less bandwidth, and speed up retrieval without sacrificing image quality.
One of the earliest formats used in CCTV systems was Motion JPEG (MJPEG). This format captures each video frame as a standalone JPEG image.
Why it was used: Simplicity and high-quality individual frames.
Limitations: Since each frame is a full image, MJPEG doesn’t utilize inter-frame compression, making it inefficient in terms of storage and bandwidth. For long-term recording or high-resolution setups, MJPEG quickly became outdated.
MPEG-4 Part 2, commonly implemented through codecs like DivX and Xvid, introduced inter-frame compression—a technique where only the changes between frames are stored, reducing file size.
Impact: A significant improvement over MJPEG, MPEG-4 became the go-to format for many early 2000s DVRs.
Downside: While better than MJPEG, it couldn’t keep up with increasing demands for HD footage and smooth playback.
With the advent of HD cameras and the need for scalable systems, H.264 (also known as AVC) became the new benchmark. Introduced in the mid-2000s, H.264 struck an ideal balance between compression efficiency, video quality, and compatibility.
Advantages:
Cuts file size by nearly 50% compared to MPEG-4.
Supports high-definition resolutions up to 8K.
Widely supported across hardware and software platforms.
Thanks to these benefits, H.264 remains the most commonly used format in current DVRs and NVRs.
As 4K and multi-camera systems became more common, the limitations of H.264 started to show. Enter H.265, or High-Efficiency Video Coding (HEVC). Finalized in 2013, H.265 delivers up to 50% better compression than H.264 at the same video quality.
Key Features:
Ideal for 4K/8K CCTV systems.
Reduces storage and bandwidth needs.
Maintains clarity even at lower bitrates.
Major CCTV brands like Hikvision and Dahua have also introduced enhanced versions, such as H.265+, which further optimize bandwidth by skipping redundant frames in static surveillance environments.
AV1 is a royalty-free codec developed by the Alliance for Open Media (AOMedia), promising performance comparable to or better than H.265.
Where it fits in: While AV1 shows promise in web streaming and media delivery, it’s still not widely adopted in DVR hardware due to its high processing demands and limited support for real-time decoding in embedded systems.
The latest evolution in video compression is H.266, or Versatile Video Coding (VVC), finalized in 2020. This format builds on H.265 and aims to reduce bitrates by another 50% while supporting everything from SD to 16K video.
Why it's exciting:
Designed for the future: 8K, 360° video, VR, and smart analytics.
Exceptional compression efficiency.
Current drawback: Despite its advantages, H.266 is computationally intensive and not yet supported by most CCTV DVRs. It remains a promising format but will take several years to become practical in surveillance.
While formats like MJPEG and MPEG-4 helped shape the early days of video surveillance, today’s systems demand more sophisticated solutions.
For most current DVR systems, H.265 (HEVC) is the best option available—offering excellent compression efficiency, quality, and broad compatibility.
H.264 remains popular and reliable, especially for legacy systems.
H.266/VVC is poised to become the next major standard, but widespread use in CCTV is still on the horizon.
If you're setting up or upgrading a surveillance system today, opting for H.265 or H.265+ enabled DVRs will future-proof your investment while significantly reducing storage costs.
