Smart A+ Hardware MPEG-4 Compression
Introducing...Smart A+ hardware MPEG-4 compression
What you need to know about software versus hardware compression Software compression (SWC) involves the capturing of images or frames by the hardware, which are later on then sent to the CPU where, using the appropriate algorithms provided by the software -- these images are compressed and stored to the hard drive as a video file. On the contrary, with hardware compression (HWC), images are captured and compressed entirely by the hardware. This process is not dependent on any software environment. What hardware compression can do for you ‘CPU loading’ is one of the troubles that SWC-based DVRs struggle with. (Many PC-based DVRs use software compression.) CPU loading is when the central processing unit (CPU) in the PC is over working. Usually, this is not a problem on systems that run a slower frame rate. However, with faster real-time systems where the processor has 400 images to compress every second, the CPU is running at near maximum capacity. This then becomes a problem. Why? Not all frames are of the same size, or they do not all require the same amount of work to process, which means the work load varies constantly regardless of the type of compression codec being utilized. Moreover, the CPU needs to process things like GUI (graphic user interface) changes, as well as control playback functions and other functions such as motion detection, network operation, etc. With the CPU already near saturation point -- should the CPU suddenly receive several large frames successively or need to run several other processes simultaneously, it can quite easily be taken over saturation point. Your everyday PC shouldn’t take this as a problem because tasks simply just wait their turn for time with the CPU, but in a DVR it becomes a big problem. Frames cannot wait to be processed, because at 400 frames every second they start piling up pretty quickly and when that happens you get 'frame drops'. This means that frames are simply ignored and they are lost. Sometimes your natural eye cannot see this and so it goes unnoticed. But in severe cases the CPU simply says: 'I have had enough' and stops working altogether. That is what happens when the PC stops responding and hangs or crashes. DV recording is an intensive multitasking process and because of this, its parts and assemblies must be robust. If underpowered, it is eventually going to break. Hardware vs. Software Compression
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