A DVR card is a device for installation in a home PC computer which converts that PC into a DVR digital video recorder by gathering video and compressing it into digital information onto a computer's hard disk drive. When all works well, this allows a home PC to record up to several surveillance cameras. However, due to reliability concerns and software glitches associated with Windows® as an operating system platform, using PCI cards to record video is not recommended. A home PC is designed to perform many operations at once, but relatively simple functions. Recording digital video requires enormous system resources like computer memory and processor attention. Complete DVR digital video recorders designed specifically to handle recorded video (and solely recorded video) offer the benefits of reliability, as well as simple setup and use, a computer card can never achieve.
PC-based Systems, Digital CCTV Systems
If you already have a PC then with the addition of a video-capture card and surveillance software you have a powerful digital system. The latest PC DVR cards offer a high specification so check your PC meets the current minimum specifications.
The purchase of a video capture card and software is a very cost effective method of providing a high specification system.
Advantages - easy to expand 4 ports to, 8, or 16 ports. Simply buy another card
- software allows many configurations for monitoring e.g. quad display
- records in real time, simultaneously from all cameras
- time and date stamping with motion detect
- alert wizard, send email with photo or video clip,
- mobile phone alert with voice,
- SMS alert
- audio alert
- MMS alert
- remote monitoring from another PC through Clinet Software, Internet Explorer or Pocket PC
- connect to Alarm panel
- low- cost all-in-one solution does away with the need for separate motion detect, splitters, quads or multiplexers.
Disadvantage - PC hard drive must have enough free space to record the camera pictures.
Compression Method refers to the computer software technique the codec in a DVR video recorder (or DVR card) uses to convert the video signal to digital information so it can be compressed and stored on digital media like a hard disk drive, DVD, or CD. Uncompressed video would require massive processing power and nearly unlimited storage capacity and is, therefore, completely out of the question in the real world. MPEG(M-JPEG) and Wavelet are the most common types of compressed digital video, but there are variants of these in addition to other proprietary formats. MPEG-1 and MPEG-2 typically offer the highest quality recording (DVDs use MPEG-2), but smaller file sizes can be obtained by using a lower tvres, more efficient compression method like Wavelet or MPEG-4. It should also be noted that the method of compression a video codec uses to compress and digitize video information may NOT always indicate the video file type / extension for playback. Instead, the final digital video format available from a DVR recorder on backup (via USB, CD or DVD burner, etc.) could be in AVI format or even a proprietary format despite MPEG compression.
On network camera market today, most products are still applying traditional MPEG-2/MPEG-4 format, a format applied for years. The traditional compression format will result in big-size file for transferring which busy the network resource and result in worse receiving performance/surveillance application. The market is demanding a high-compressed solution but maintain the same video quality or even better than ever before. And now this demand is heading for a new generation compression format so called H.264 which can achieve savings of bandwidth and high performance of transferring video.
Why H.264 compression technology?
The new industry standard H.264 compression technology is causing a revolution in the Video world, enabling higher quality, lower bit rates, lower system cost and new applications. New H.264 system provides the same low-latency video that has been delivered by traditional MPEG-4 based systems but with a reduction of up to 50% in bandwidth and storage requirement – or to put it another way, H.264 system can deliver significantly higher video quality for the same bandwidth – to save your internet resource(or higher transmission speed) and hard disk place also.
H.264 compression advantage:
Higher compression rate ensures extra compression can be achieved when there is low activity in the video – a situation common in many surveillance applications. Advanced coding techniques mean that high-quality video can be maintained during fast-moving activity without frames being dropped – an important issue for applications such as Casio gaming table surveillance.
High-quality video can be maintained during fast-moving activity without frames being dropped, regardless of bitrate and motion. This is paramount in applications such as casino gaming table surveillance.
Low cost, high performance encoding of 4SIF 30fps video that is fully compliant with H.264.
Field upgrade to existing installations as compression standards advance.
Real time analytics algorithms can be executed in high performance dedicated hardware rather than in software. Doing this at the edge of the network, i.e. at the camera, makes for a truly scalable solution.