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7.2.2 MPEG-4
When MPEG-4 is mentioned in video surveillance applications, it is usually referring to MPEG-4
Part 2, also known as MPEG-4 Visual. Like all MPEG (Moving Picture Experts Group) standards,
it is a licensed standard, so users must pay a license fee per monitoring station. MPEG-4
supports low-bandwidth applications and applications that require high quality images, no
limitations in frame rate and with virtually unlimited bandwidth.
7.2.3 H.264 or MPEG-4 Part 10/AVC
H.264, also known as MPEG-4 Part 10/AVC for Advanced Video Coding, is the latest MPEG stan-
dard for video encoding. H.264 is expected to become the video standard of choice in the
coming years. This is because an H.264 encoder can, without compromising image quality,
reduce the size of a digital video file by more than 80% compared with the Motion JPEG format
and as much as 50% more than with the MPEG-4 standard. This means that much less network
bandwidth and storage space are required for a video file. Or seen another way, much higher
video quality can be achieved for a given bit rate.
H.264 was jointly defined by standardization organizations in the telecommunications (ITU-T’s
Video Coding Experts Group) and IT industries (ISO/IEC Moving Picture Experts Group), and is
expected to be more widely adopted than previous standards. In the video surveillance industry,
H.264 will most likely find the quickest traction in applications where there are demands for
high frame rates and high resolution, such as in the surveillance of highways, airports and
casinos, where the use of 30/25 (NTSC/PAL) frames per second is the norm. This is where the
economies of reduced bandwidth and storage needs will deliver the biggest savings.
H.264 is also expected to accelerate the adoption of megapixel cameras since the highly
efficient compression technology can reduce the large file sizes and bit rates generated without
compromising image quality. There are tradeoffs, however. While H.264 provides savings in
network bandwidth and storage costs, it will require higher performance network cameras and
monitoring stations.
Axis’ H.264 encoders use the baseline profile, which means that only I- and P-frames are used.
This profile is ideal for network cameras and video encoders since low latency is achieved
because B-frames are not used. Low latency is essential in video surveillance applications where
live monitoring takes place, especially when PTZ cameras or PTZ dome cameras are used.
CHAPTER 7 - VIDEO COMPRESSION
