DVR standards

The market demand for the best,  fastest and highest quality products push us to continuously develop new and better products.  From the old analog tape based video recorders, the industry standard is now digital video recorders, storing compressed TV quality videos (CIF) at 30 frames per second.  Compression standards have likewise improved over the years, starting with Motion JPEG, then MPEG-4 and now H.264 (also known as MPEG-4 part 10).    Positioning one's product above this standard, at the lowest possible price, is the sweet spot for most manufacturers.  Some products sell just on low price alone and totally forget about quality and performance, while some offer the best performance and quality at prohibitive prices.  What is the sweet spot in positioning?  What is the minimum standard?  What is the best price? 

In my opinion, a decent DVR should have the following features:

• Real-time recording (30 frames per second - Note: Movies run at 24 frames per second) on all cameras for at least CIF size
• MPEG-4 compression
• Recording capability of up to D1 size (better known as DVD quality)
• Network capability (This includes video streaming thru LAN or the internet, remote setup and remote viewing)
• At least triplex operation (Simultaneous operation for recording, search and playback and live view)

Some ultra cheap designs are available in the market but are lacking in some basic features, which goes to show that there is no such thing as "free lunch :)".  What are the possible downside to missing out some of the basic features?

• Missing out important frames due to frame rate limitations.  Imagine split second action that results to damaged property, missing goods or worse, lost lives.  You don't want your video evidence to leave whodunit questions unanswered.

• Why compression?  Yes, storage is cheap, but it shouldn't be a reason why you should waste money on extra storage.   Uncompressed video takes a huge amount of storage space, regardless of whether you're storing it on a hard drive, DVD or digital tape. To imagine how much space is required, consider that a typical uncompressed still frame of video, at the quality most of us are used to viewing, requires just under one megabyte to store. Video typically plays at 30 frames per second. This means that your typical uncompressed video might occupy 27 megabytes per second to store. Do a little more math, and you'll soon discover that the new 80 gigabyte hard drive that came with your computer will only store about 50 minutes of raw, uncompressed video. Do one more calculation and you'll see that a DVD disc (at 4.5GB) can hold less than three minutes. Clearly, we need some form of digital compression to reduce that file size.  The second issue is so closely related to the first that it's really the same problem viewed from another angle. Imagine you have an uncompressed VHS-quality video file sitting on a hard drive, ready to play. In order to provide smooth playback, your hard drive would have to dump data to your computer at a sustained 27 megabytes per second (or, as an engineer would think: 216 megabits per second [27 x 8 bits/byte]). Storage systems are available that can hit these speeds, but they're very expensive. Now consider that you want to deliver that same video to the masses, via the Internet. Whatever technology you use, the speed of that technology (bandwidth) would have to match that 27 megabytes per second, without fail.  
• D1 capability is needed if you want that extra resolution to positively identify objects or people which otherwise would have been unrecognizable.  It's better to have a snapshot of a recognizable face rather than a barely recognizable blob, especially at a distance.

• Network capability?  Remote monitoring and remote setup capabilities add a factor of more than 100 to the useability and convenience of using a DVR.  Imagine, visiting each and every DVR, especially for multi-site installations.  
• Multiplex operation?  This is the most overlooked feature in DVRs.  You don't want recording to stop, just because somebody is viewing via the network or somebody is adding a user to the DVR.