A PVR or DVR is a means of recording digital TV signals. With increasing use of HDTV, the DVR/PVR devices need to have more capability. This article looks at the cable STB, DTH STB, and PC based alternatives of the DVR/PVR. Some actual product examples are discussed.
Unlike the VCR of old days, the personal video recorder or the PVR is a processor based application. One big difference is VCR was analog, recording analog TV/video signal on a magnetic tape. The PVR handles digital data and records the digital data stream that is the digital TV/Video signal. The digital TV/Video signal is also a compressed signal. Digital data created out of the digitized video is a few orders more that what the analog signal would have needed. The signal is compressed and the techniques are known as MPEG2 and MPEG4. The current and most efficient compression in the MPEG4 scheme is the H.264 encoding method.
PVRs are able to handle this digital data. A PVR may operate on your PC making it easy to record video on it. It could be part of the set top box that has been provided to you by the cable service operator or the DTH ("Direct to the Home") satellite service operator. It can also be part of the converter box that you need to catch digital TV transmitted over the air now that analog TV is dead!
Advantages of PVR/ DVR
The PVR is able to do scheduled and unattended recordings. It can skip ads while recording, and you can record a program on a channel other than the one that you are viewing. Some PVRs will even let you set the recording schedule remotely via the Internet. For this purpose you can even access a website from the program provider that gives you the time schedule of specific programs broadcast by the channels. The ability to pause live TV is an interesting new feature not possible in anything other than a DVR. Thus if your cable service operator or the DTH operator offers a set top box with PVR for a reasonable additional subscription/cost, it will make sense to subscribe to that.
HDTV implications on PVR
Increasingly TV programming is in high definition or HD format. Commercial movies on DVDs are in HD format. In fact, most videos are changing over to the HD format. Your TV at home probably has already changed to a HD unit. We have already discussed how digital video data produces much more data than in analog format. HD television increases even that. That is mainly because the resolution of the pictures that you see on a HDTV is much more than what it use to be in standard definition television earlier.
Whereas standard definition (SD) TV such as NTSC format reproduced 720 x 480 the full HD pictures (ATSC format) carry signal about 1920 x 1080 pixels. That again is a few times more even in digital format compared to the standard definition TV. The picture frame time or the time for which one picture frame is shown on your TV has not changed between the SD and the HD standards. What that means is that the PVR for HD has to handle many times more data than a digital SD recorder. The implications are that a more powerful processor has to be used to run the PVR application. This has a direct cost implication, and you can expect HD PVRs resident in various flavors of set top boxes and the digital TV converter boxes to be more expensive than just SD capable recorders.
The set top box from Motorola is an example of a PVR (DVR) inside a set top box (STB). Cable TV providers offer for as little as $10 a month a fully functional High Definition DVR with over 100GB of storage space and Dual-tuners. Many of these cable providers use the Motorola product. Satellite DTH providers Dish Network as well as Direct TV provide a PVR/DVR option.
ATI makes the HDTV WONDER, a PCI card for analog TV, over-the-air digital TV, and full quality free over-the-air HDTV reception with a DVR. You can turn your PC into a HD TV recorder. You would be able to receive over the air HD TV broadcasts also with an antenna that is available for purchase.