What our experts say…
You would have thought that whoever was responsible for one of the most important developments in network video technology would have called it something a little more interesting than H.264. The blame lies with the ITU (International Telecommunication Union) and its Video Coding Experts Group and we should be grateful they didn’t opt for the alternatives: MPEG-4 Advanced Video Coding or MPEG- Part 10.
For those of you that didn’t already know, H.264 is a highly efficient video compression system, it’s actually been around for a while (Sony has been using it for at least a year) but what makes it so special is the low bitrate, which basically means high quality images can be sent over computer networks and the Internet using fewer bits than comparable compression systems.
In theory, picture quality should be in the same ballpark as established systems like MPEG-2 and MPEG-4 but as it uses a fraction of the number of bits more video streams can be sent from more cameras over slower networks, without significantly compromising quality.
It’s also notable that Axis, the most venerable and one of the most experienced manufacturers in the field of IP video has given it its blessing and is now using H.264 on its latest range of network cameras.
One of the compression technology’s first outings under the Avis banner is on the P3301 Fixed Dome Network Camera, which features dual MJPEG/H.264 streams.
To give you an idea of what H264 means in practice, the standard MJPEG stream operates at between 8 and 10 Mb/second; H.264 on the other hand manages to get by with just 0.5 and 0.8Mb/s (it supports multiple streams) so by any reckoning that is a substantial reduction, but what’s the catch? You’ll have to wait for our performance assessment to find out because this is the point we look at what else it can do.
As usual we’ll begin at the business end, with the lens and image sensor. The former is a high quality item, a Varifocal type 2.8 – 10 mm, F1.3, with a DC-controlled auto iris; the horizontal angle of view is 23 – 72 degrees. Sitting behind the lens is a 0.25-inch progressive scan CMOS CCD. Minimum illumination is rated at 1.5Lux but Axis makes no mention of the pixel count. However, CCD numbers are to some extent academic on network video systems due to the high level of processing and constraints at the display end.
By the time the image has been through the digital mill and shoehorned into a browser window screen resolutions range from 160 x 120 to 640 x 480 pixels, at 30 fps in all modes.
It has a useful range of manual and exposure options; the shutter, for example, goes from 1/4 sec to1/20000th sec. There’s provision for a privacy mask, it has what Axis describes as ‘enhanced’ motion detection and file upload via FTP, HTTP and email notification of alarm events, which includes camera tampering (loss of image for a preset period). There’s a built-in 64Mb video buffer memory for storing pre and post alarm events and it supports two-way audio (it has a built in microphone).
The dome is a compact design and Axis claim it is tamper resistant, which basically means any would-be tamperer needs to go equipped with a hollow ended Torx driver to remove the cover. Axis thoughtfully provides one in the box by the way. Inside the camera sits on a simple three-axis gimbal mount and this is attached to a lozenge shaped module that contains all of the camera processing and network communications circuitry.
Connections to the outside world are mounted on the opposing edges of the module. On one side is the DC power socket (it can also be powered by POE or power over Ethernet) a 5-volt DC adaptor is included. Next to that is the reset button and two LEDs for indicating power on and network connection.
The RJ-45 Ethernet socket comes next and last but not least is a bank of four spring terminals for the alarm input and output and a 3.3 volt power feed for external devices. On the opposite side is a pair of 3.5mm minijack sockets for the audio input (microphone) and output (line level).
Other items of interest include a power on light on the edge of the module, which is visible through a transparent piece of plastic on the dome housing. On the opposite edge is the built in microphone. The standard of construction is very good indeed, especially the camera mount which moves freely in all directions, making it easy to align, and it’s locked securely in position using knurled thumbwheels.
Setup and operation
Axis network cameras have become progressively easier to set up over the years and the P3301 is no exception. Once the camera is powered up and connected it’s a simple matter to find it on a network PC using the IP utility on CD ROM that is supplied with the camera. This also allows the installer or end-user to change the IP address if the default conflicts with other devices. It’s all very simple to use and virtually painless. Just remember to disable the Firewall or grant the IP utility access, (we always forget resulting in five minutes of fruitless head-scratching…).
After entering the camera’s web address into the browser, the user is asked for a username and password, after which point the camera’s Home Page is displayed. The P3301camera is designed to work best with Internet Explorer and, if being used for the first time, the user is asked to install a set of Active X add-ons and H.264 codecs.
The MJPEG stream will display in Firefox but the image lag makes it virtually unusable, there doesn’t seem to be a H.264 codec available and there’s no access to the setup menu. It might be possible to jiggle the settings to make it work a little better but it looks like being an uphill struggle.
The ‘Live View’ browser window has a familiar look to it though there is one new feature, called Stream Profile. This is a drop-down menu on the top left hand corner of the display window and in addition to the MJPEG and H.264 options there’s a choice of ‘Quality’, ‘Balanced’, ‘Bandwidth’ and ‘Mobile’. These correspond to four preset resolution and compression settings but they can be modified in the setup menu, which we’ll come to in a moment.
Along the lower edge of the screen are three icons for freezing the image, taking a still snapshot and enlarging the image to full screen. Clicking Setup in the top right hand corner opens the main menu page. There are six main categories: Basic Setup, Video & Audio, Live View Config, Events, System Options and About. The first five lead to a series of sub menus. There’s far too many to go into in any detail here but they are all very well laid out and easy to use. Moreover, they’re backed up by an excellent and well written Help menu.
Suffice it to say there is an extraordinary amount of control over virtually every aspect of the camera’s operation, from the basics, like colour, brightness, contrast, white balance and setting up exposure zones, to specifying the colour of up to three privacy masks.
Motion detection setup is also very straightforward and involves dragging and resizing rectangular ‘triggers’ on the screen (up to 10 can be created). The ‘enhanced’ features are supposed to make it less vulnerable to false triggering (sudden changes in lighting level, picture noise etc.). It worked well enough in our tests but it didn’t seem noticeably more discriminating than rival products.
Performance
So is there a catch? Well, there are some differences between the MJPEG and H.264 streams but we have to say that they are so small that you would probably go boss-eyed trying to spot them. In just about every important respect the quality of H.264 is as good as MJEG (in some cases better…). In a nutshell image quality is very good with fewer than expected processing artifacts, there’s little in the way of image lag and in a well-lit scene picture noise is negligible.
At the highest resolution setting – and on a normal network and in view of the low bitrate there seems to be little incentive to use a lower one – the image is pin-sharp (though bear in mind this is a 1/4 screen sized insert in a browser window). When blown up to full screen size it will start to look a bit ragged around the edges, with the defects and processing artifacts more clearly visible.
Colours are accurate and well defined and the camera’s exposure system tackles variations in brightness, whether they’re slow or fast, without any difficulty. If, for some reason, it falters or the lighting conditions are especially awkward there’s almost certainly a manual adjustment in the setup armoury to compensate.
Low light performance is okay but not exceptional by current standards. As light levels fall there is a marked increase in noise and digital artifacts and ironically they seem to be worse on the higher bitrate MJPEG stream
Image stability is excellent and its brief encounter with the SI rubber mallet made no impression on it whatsoever.
Overall assessment
Despite our best efforts, we can find no significant drawbacks to the use of H.264 on IP cameras and this implementation by Axis is virtually flawless. Performance is very good indeed but when it comes to what the user or operator sees on the screen, and compared with previous Axis cameras and rival products, the P3301 has no extra special qualities. However, under the bonnet is where it all happens and it begs the question, how long will it be before H.264 becomes the de facto standard for all network systems?
What the manufacturer says…
The Axis P3301 Network Camera is a fixed dome professional security camera specifically adapted for unobtrusive video surveillance in exposed indoor environments, such as retail, banking, government buildings, schools, universities and airports. The camera is very compact, measuring 144mm in diameter with a depth of just 94mm. It offers superior image quality with progressive scan and wide dynamic range, providing crisp and clear images of both illuminated and low-light areas.
The camera is part of Axis’ new generation network video solutions which offer simplified deployment and management of large-scale video surveillance systems, more cost-efficient system solutions and higher image quality and optimised video streams.
Multiple H.264 and Motion JPEG streams can be provided from the Axis P3301 simultaneously either in full frame rate or individually optimised for different quality needs and bandwidth constraints. H.264 is an open, licensed standard that supports the most efficient video compression techniques available today. Without compromising image quality, H.264 compression reduces the size of a digital video file by more than 80 per cent compared with the Motion JPEG format and by 50 per cent compared with MPEG-4 Part 2 file. This means that much less network bandwidth and storage space are required for a video file or much higher video quality can be achieved for a given bit rate.
The standard Axis P3301 comes with a tamper-resistant plastic cover, while the Axis P3301-V variant features a rugged, vandal-resistant casing with a metal base specifically adapted for environments subject to the risk of vandalism. Power over Ethernet (IEEE 802.3af) supplies power to the camera via the network, eliminating the need for power cables and reducing installation costs.
The Axis P3301 Network Camera include video intelligence such as enhanced video motion detection, audio detection and detection of camera tampering attempts such as by blocking or spray painting for example. It offers the market’s most advanced suite of security and network management capabilities, including HTTPS encryption with preserved performance, IEEE 802.1X authentication, IPv4/IPv6 and Quality of Service.
