An alternative is that some satellite or (more commonly) cable set-top boxes have a FireWire port that can be connected to a computer. The recorded MPEG stream can be relayed to the computer via this FireWire port; though it can be done live, this is more commonly used for transferring shows from a set-top box with built-in DVR.
Some of the technical details for DVR is given to you below:
1. Designed for rack mounting or desktop configurations.
2. Single or multiple video inputs with connector types consistent with the analogue or digital video provided such as coaxial cable, twisted pair or optical fiber cable. The most common number of inputs are 1, 2, 4, 8, 16 and 32. Systems may be configured with a very large number of inputs by networking or bussing individual DVRs together.
3. Looping video outputs for each input which duplicates the corresponding input video signal and connector type. These output signals are used by other video equipment such as matrix switchers, multiplexers, and video monitors.
4. Controlled outputs to external video display monitors.
5. Front panel switches and indicators that allow the various features of the machine to be controlled.
6. Network connections consistent with the network type and utilized to control features of the recorder and to send and/or receive video signals.
7. Connections to external control devices such as keyboards.
8. A connection to external pan-tilt-zoom drives that position cameras.
9. Internal CD, DVD, VCR devices typically for archiving video.
10. Connections to external storage media.
11. Alarm event inputs from external security detection devices, usually one per video input.
12. Alarm event outputs from internal detection features such as motion detection or loss of video.
Many DVD-based DVRs are equipped with two DVD drives or an additional internal hard drive. This arrangement can be used to copy content from a source DVD, which is disallowed in the U.S. under the Digital Millennium Copyright Act if the disc is encrypted. Most such DVRs will hence not allow recording of video streams from encrypted movie discs.
Some DVD-based DVRs incorporate a Firewire connector which can be used to capture digital video from a MiniDV or Digital 8 camcorder, possibly recording a simple DVD as the camcorder is played back. Some editing of the resulting DVD is usually possible, such as adding chapter points.
Digital video recorders configured for physical security applications record video signals from closed circuit television cameras for detection and documentation purposes. Many are designed to record audio as well. DVRs have evolved into devices that are feature rich and provide services that exceed the simple recording of video images that was previously done through VCRs. A DVR CCTV system provides a multitude of advanced functions over VCR technology including video searches by event, time, date and camera. There is also much more control over quality and frame rate allowing disk space usage to be optimized and the DVR can also be set to overwrite the oldest security footage should the disk become full. In some DVR security systems remote access to security footage using a PC can also be achieved by connecting the DVR to a LAN network or the internet.
