H.264 is a buzzword throughout the industry. Since the first version of the H.264/MPEG-4 Part 10 compression standard was released in 2003, there have been multiple revisions, improvements and enhancements that have made the technology attractive for use by both consumer and professional video manufacturers. H.264 compression has greatly improved picture quality while also dramatically reducing the amount of data required to produce high-definition (HD) video coding. These are proven benefits that have impacted the larger market for broadcast/commercial video before migrating to the security video market. These capabilities justify much of the hype, but there are also several practical facets to be considered related to H.264.
Be wary of using H.264 with Windows-based video management software. The Microsoft standard file systems are not suitable for large sequential files needed to store H.264 streaming security video. Windows operating systems are designed for general file use. Microsoft’s FAT32 and NTFS standard file systems are suitable for JPEG file storage since each file is relatively small, and modern hard disk drives (HDDs) can skip from one small file to another quickly. However, storage for H.264 streaming files requires continuous, not fragmented, files that are laid out sequentially on the HDD for the fastest writing and retrieval. In a Windows system, over time, more files are broken up because of how the file system operates and fragmented files are not conducive to fast writing and retrieval of video. File fragmentation may cause these systems to degrade over time and lower performance. The situation may require a dealer/integrator to make an expensive trip to a customer’s site to “defrag” the system, which involves shutting down other functions during the process.
An alternative is to use a non-Windows-based network video recorder (NVR) appliance in which video files sizes are of appropriate length (about five to 15 minutes) and laid out on a storage system in an efficient manner. In this case, expensive fast hard drive write technologies such as the new 15,000 RPM disk drives are not needed. Standard SATA/3-gigabit-per-second HDDs at 7,200 RPM are sufficient in a properly designed recording system. Although the price of solid state HDD is coming down, there is still a large cost-per-gigabyte difference between solid state HDD and SATA. In H.264 applications especially, users may benefit from a video recording appliance (rather than a PC) that uses a flat sequential type of file system. Another alternative is a video management software application that runs under Windows but uses a specially formatted partition or HDD for video storage.
Not all H.264 files are alike. Security video solutions differ regarding how they implement H.264. Various compression profiles are built into the specification and different profiles are used for various applications. Each one has its pros and cons. The H.264 baseline profile is intended for small portable devices, such as portable video games, that have limited CPU devices and memory sources to decode the video. H.264 baseline profile is also used in video conferencing applications. As the name implies, baseline profile is considered a minimum quality specification. Many security recording solutions will either re-encode the video to H.264 baseline profile or record in the camera’s native H.264 baseline profile.
Others cameras and recording devices use H.264 high profile, which goes beyond the minimum standard to provide a higher level of compression (and smaller video streams) while maintaining high-quality HD video. This is the profile used by Blu-ray storage devices and broadcast HDTV. However, high-profile H.264 requires a more powerful computer chip inside the camera and more CPU power on the decoding side, too.