TOOLBOx: Technical Tips and Info

Video Format Trends in the IP Camera Market

Silicon and Demand for Interoperability Drive Compliance with Standard Codecs

by Steven Goodridge, Ph.D.

When connecting an analog security camera to an analog video recorder or monitor, one rarely considers whether the devices will work together. The NTSC and RS-170 analog video standards followed by hundreds of manufacturers virtually guarantee that if the products were purchased in the USA and the connectors fit, the video will come through intact. In the computer-driven digital video world, however, things never seem so certain. As standalone DVRs replaced tape-based VCRs for CCTV recording, a myriad of different proprietary video formats emerged. Now the future of video security is over IP, where every camera will digitize and compress the video remotely. What will this mean for the variety of video formats that video analysts will encounter?

The IP Camera Marketplace

Today over 1000 different models of IP video security cameras are advertised for sale by over 100 different manufacturer brands1. Many devices have specialty features such as pan-tilt movement, low light operation, and high resolution, each of which may be useful in a different part of a single security system installation. But systems integrators require that all of the cameras they install interoperate with the video software they deploy. The functionality of the network video recorder (NVR) software is of primary importance in a video security system installation. If a camera is sold bundled with NVR software, that software is typically weak on features and may only work with that manufacturer’s cameras. By comparison, enterprise-class NVR software is typically a third-party product that will work with many camera makes and models. As prices for IP cameras continue to drop (some are available for under $200) they have become commodity items, and those that do not interoperate with the leading NVR systems will see their deployment limited (in some cases, marketed only for private home use).

Popularity of Standard Codecs

Most camera manufacturers have pursued interoperability by using standard-compliant implementations of popular video codecs and network protocols. Over 60% of IP cameras on the market support the MPEG-4 (Part 2) or baseline H.263 (“MPEG-4 Short Header Mode”) video standards. Over 50% support some form of JPEG video transmission, and 18% support H.264. Only about 4% of devices on the market produce some other format
of video1. For maximum interoperability, many cameras support both JPEG transmission and one other, more bandwidth-effi cient codec. JPEG is a popular “lowest common denominator” video codec in IP cameras because support for decompressing JPEGs is built into virtually all web browsers.

Standard Solutions in Silicon

Another factor contributing to increased support for standard video codecs in IP cameras is the availability of ASIC components that implement high-performance standard codecs, such as IndigoVision’s IV8103 MPEG-4 chip and HiSilicon’s Hi3510 H.264 chip. ASIC technology allows computationally intense video compression operations to be performed with less power and at lower hardware cost per camera. The improved video quality, reduced data rate requirements, and lower cost of such ASIC-based cameras is driving older, programmable DSP-based camera designs into obsolescence.

Integration Challenges

NVR manufacturers pursue interoperability by testing their software on dif ferent cameras and augmenting their camera driver software as necessary. An NVR package may include hundreds of software drivers for different camera models. Besides decoding the video stream, NVR software must also be able to start and stop a video stream, and may provide other controls such as pan, tilt, and image characteristics. At present, many of these additional controls have proprietary implementations on each manufacturer’s brand of camera, which causes difficulty for NVR vendors and systems integrators. An NVR developer must obtain the communications protocol for each camera model from the manufacturer or develop their software to use the manufacturer’s proprietary software developers kit. This complexity led to a recent industry effort spearheaded by Axis, Bosch and Sony to standardize interfaces for network video products.

Fortunately, the syntax of video bitstream itself tends to vary much less from manufacturer to manufacturer because of the market-driven popularity of standard video codec implementations.

File Formats

Network video software such as an NVR may store video to a non-volatile file in a variety of ways. Typically, the video data will not be recompressed, as this would result in quality reduction and require significant processing resources, but the video data may be wrapped in either a proprietary or standard file container. Some NVR application requirements such as continuous recording, simultaneous recording/playback with time shift, multiplexing of many cameras, and storage of metadata may compel the use of a proprietary container file for surveillance data storage. However, most NVR systems allow the export of video clips to standard file formats. If the original recording was made using a standard video codec such as MPEG-4 Part 2 or H.264, it is technically feasible for the expor ted clip to be made using an appropriate standard file container (such as MP4) without recompression. Some NVR products allow optional reformatting and/or recompressing the video to a different codec when exporting a clip. Care should be taken to avoid such conversions where the quality of the exported clip is important.

The Future

At the time of this writing, many IP camera manufacturers (such as Axis Communications) have announced new product lines based exclusively on H.264 ASIC components. H.264 provides superior video compression efficiency and quality compared to other standard codecs, is used by many HD camcorders and is supported by Blu-ray disc players and many network-attached media extenders. This common codec provides the capability for both standard and high definition video to be transported from cameras to computers and consumer television components for archival and playback without any recompression artifacts. It is therefore likely that H.264 will gradually replace MPEG-4 Part 2 for IP video applications.

About the Author

Steven Goodridge, Ph.D., develops digital video surveillance and forensics technology at Signalscape, Inc. in Cary, North Carolina.