A Digital Video Recorder (DVR) or Personal Video Recorder (PVR) is a device that records video in a digital format to a disk drive or other memory medium within a device. The term includes stand-alone set-top boxes, Portable Media Players (PMP) and software for personal computers which enables video capture and playback to and from disk. Some consumer electronic manufacturers have started to offer televisions with DVR hardware and software built in to the television itself; LG was first to launch one in 2007. A digital camcorder combines a camera and a digital video recorder. Also, mobile phones often have a camera as well as some digital video recording capability.
Hard disk-based DVRs
The two early consumer DVRs, ReplayTV and TiVo, were launched at the 1999 Consumer Electronics Show in Las Vegas, USA. Microsoft also demonstrated a unit with DVR capability but commercial availability of this software would have to wait until the end of 1999 for full DVR features in Dish Network's DISHplayer receivers. TiVo shipped their first units on March 31, 1999, and now in March it is celebrated as a company holiday, known as 'Blue Moon'.
Digital Video Recorder Basics
A DVR is a glorified hard drive inside a fancy box that looks nice in the entertainment center. The hard drive is connected to the outside world through a variety of jacks on the back of the box, usually it is typical RCA connections to use to hook up, say, a cable box or a VCR.
The television signal comes into the DVR's built-in tuner through antenna, cable or satellite. If the signal comes from antenna or cable, it goes into an MPEG-2 encoder, which converts the data from analog to digital (MPEG-2, by the way, is the compression standard used to fit information onto a DVD). From the encoder, the signal is shipped off to two different places: first, to the hard drive for storage, and second, to an MPEG-2 decoder, which converts the signal back to analog and sends it to the television for viewing.
Some systems use dual tuners, allowing users to record different programs on different channels at the same time. On a few systems, it can be even record ed two programs while watching a third pre-recorded show.
The device is driven by a customized operating system-for instance, in the case of TiVo, the machine runs on a highly modified Linux installation. The operating system resides on the hard disk, along with the recording space, a buffer for live broadcasts, and in some cases a space for future expansion.
While the system might seem pretty different on first analysis, the digital storage of television signals opens up a whole new world of possibilities when it comes to playback and viewing.
Satellite TV and Digital Cable
In the case of satellite TV systems or digital cable, no encoders are used within the box because the satellite or cable company has converted the signal to digital already. This results in higher picture quality than on analog cable or antenna systems.
First, a DVR is tapeless. With a VCR, the device itself is merely a recording tool; the blank cassette is the media. In a DVR, the media and tool are one and the same. DVRs can be incorporated into the home network, and be allowed to access system remotely. DVR is even capable to record a specific show from halfway across the world with just a few clicks of the mouse.
Perhaps the most important benefit of DVRs is the unprecedented control over “playback.” A VCR, requires to wait for a program to finish recording before it can started to watch. Since there's no tape to rewind, digital recording doesn't have this limitation. A program that started recording 10 minutes ago can be viewed at any time, even while it's still recording.
Advantages to Consumers
• Ease of use,
• Advanced search capabilities,
• Simultaneous record and playback,
• No image degradation, improved compression and storage,
• Integration potential,
• Remote management and so on. Besides , DVR is:
• Easy to install and use: IPTV DVR attaches directly to the IP network. Its built-in Web interface allows for simultaneous viewing, recording and playback of video sequences via the standard Internet Explorer from anywhere on the network.
• Optimized storage: It uses Axis Prioritized Video Storage technology, which makes more efficient use of valuable disk space to preserve video recordings longer.
• Secure storage: The images are sequentially recorded on different hard disks to prevent loosing entire recordings from an unexpected hard disk failure.
Tata Sky has recentaly launched its DVR service, Tata Sky Plus. It is said to have sold about 30,000 units since its launch about three months ago, less than 10 per cent of the Tata Sky subscriptions sold in the same period, informed sources said. Because of the cost of its DVR boxes, Tata Sky could be giving a subsidy of Rs 5,000-8,000 on every connection of Tata Sky Plus. According to a projection made by Media Partners Asia, the combined operating losses of DTH companies will cross Rs 2,000 crore in 2008-09.
The sale of DVR service comes with heavy cost implications to DTH service providers, which only adds to their existing financial burden of offering the basic DTH services. Some of the existing DTH players are holding back the launch of their DVR services for this reason.
Alll said and done, a DVR is a milestone which will dramatically enhance the viewing experience for its subscribers. It will give subscribers ultimate control over what they watch and when they watch it. Therefore, a DVR may fast become a technology of choice.