Hard disk recorder

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A hard disk recorder , also known as a video disk recorder , is a recorder that digitally records video or audio onto a hard disk . Most set-top boxes / receivers have this function, usually referred to as PVR ( Personal Video Recorder ).

Functions

As a further development of the conventional video recorder , which saves the data - in most video systems used in the home - analog on magnetic tape cassettes , the hard disk recorder records the data digitally on a medium common in computer technology, usually a hard disk . If no digital signal is supplied or received, the hard disk recorder must convert the analog signal using a built-in analog / digital converter.

The recordings saved on the hard drive can be played back directly. There is no need to rewind or fast forward and the quality remains the same even after repeated playback, as there is no wear and tear, as is known from video tapes. With an additional DVD burner, the data can also be burned onto a DVD for archiving and exchange.

In particular, time-shift television , usually called time shift , is a popular function in hard disk recorders. The additional availability of an electronic program guide (EPG) greatly simplifies the selection of the programs to be recorded.

Some devices have a slot for memory cards or a USB / eSATA connection, via which pictures, audio files and often films can be played and imported onto the hard drive in the PVR. In some cases, but not with all devices, the USB connection of PVRs enables recording on an external storage medium and export from the internal hard drive to an external storage medium.

Panasonic hard disk recorder

Recording capacity and hard drives

Hard disk recorders have a recording capacity of up to several hundred hours, depending on the capacity of the hard disk and the compression rate of the films.

The available recording capacity depends on the type of recording. Recorders that record analog signals must first digitize them. In order to increase the recording capacity, the compression can be greatly increased, but this leads to a significant deterioration of the image. If digital signals ( DVB ) are recorded, they are saved directly without any computational effort. With SD image material, around 1.5 to 3 GB of storage space is used per hour of video (depending on the encoding of the television station); with HD recordings , a film can also be 6–10 GB or more per hour, depending on the quality of the broadcast take in place. The size also depends on the broadcast audio standard, such as Dolby Digital or the subtitles it contains.

Meanwhile (as of October 2009) there is a large selection of DVB hard disk recorders as multituners with up to 6 DVB-S / DVB-S2 receivers at the same time or mixed operation between different types of reception and with DVD or BR drive. There are also devices for terrestrial reception ( DVB-T ). Panasonic and Samsung offer models with DVD recorders for satellite reception ( DVB-S / DVB-S2 ). There are also many devices for digital cable reception ( DVB-C ), as well as for HD reception.

Integrated hard disks are available in the sizes customary on the market. Recorders with built-in, exchangeable or mobile hard disks are also offered; nothing has to be deleted here. When the memory is full, connect another hard drive. A few devices offer streaming of the data directly to a server (NAS) via the network interface.

Some manufacturers now offer hard drives that are optimized for such digital media devices. These are usually cooler, quieter, more energy-saving and, compared to PC hard disks, optimized to simultaneously record and reproduce several large and time-volume data streams evenly and continuously (streaming).

In addition to hard drives, USB sticks are often used as a medium. However, these are mostly slow, expensive, with low capacity due to their design and often do not allow multiple recordings or no timeshift, if they are fast enough at all.

Blu-ray recorders are also available that can receive, save and write films and programs in full HD quality and write them to Blu-ray Disc .

Recording media formats

The basic formatting of the hard disk of the device, which is necessary for operation, poses a certain problem , as it may U. can bring restrictions.

The palette ranges from FAT32 to Ext2 , Ext3 , NTFS and JFS to in -house systems, depending on the manufacturer and the operating system used . The recorded files are also often split into several parts (i.e. saved in pieces).

For example, with the outdated FAT32 file system, the system-related maximum file size is 4 GB. When copying a longer film to a PC, you can quickly get several files instead of one contiguous file. Therefore, more modern, unrestricted file systems are recommended for receivers, which are usually supported free of charge by different operating systems.

However, some manufacturers always split their recordings, even if the file system used would allow larger files.

Personal Video Recorder (PVR)

A personal video recorder ( PVR ) or Personal Video Recorder [ ˈpɜːsənəl ˈvɪdiəʊ ɹɪˈkɔːdə ] is a video recorder with a hard disk drive instead of the usual tape drive that “remembers” the user's program preferences and offers him a program stored on the hard disk according to his interests, often in combination with time-shifted television, which makes it possible to watch a program while it is still being recorded.

Recording of a TV program on USB storage media with a DVB receiver.

PVR are usually with one or more DVB - receivers available, wherein the received DVB stream is unchanged on the hard disk. Equipment with two tuners (twin tuners) usually allows you to watch one program and record another at the same time, possibly also to watch a second program as picture in picture , and rarely to record two different programs or program bundles at the same time. Equipping a DVB-PVR with an analog input ( SCART ) does not usually allow the recording of external sources, but only allows them to be looped through to screens with too few inputs.

Some devices have a DVD recorder built in in addition to the hard disk . Depending on the device the DVD recorder allows a removable memory as the recording media or archiving of articles that have been recorded on the hard drive. Cutting and copying the stored transport stream to DVD is much easier with such devices than having to transfer the recorded film, for example, to a powerful PC first, in order to then edit it with special software, cut it and then convert it into a program stream DVD - specification to convert and also provided with navigation aids for a DVD player and then burn.

Internet-based PVR

In addition to stationary devices, internet-based video recorders can also be used. The devices are located in a data center connected to the Internet and are programmed by the user via the Internet. Such devices are sometimes also referred to as “Network Digital Recorders” (NDR). The recorded programs can either immediately via streaming or transmitted via download. The network recorder can record an unlimited number of programs at the same time and gives its user not only temporal but also spatial independence from the TV program. The Supreme Court is the judgment of 22 April 2009 - I ZR 216 / 06- Internet-based video recorder that only one who is responsible for copying, "the most technically accomplished the physical setting of the radio program".

Alternative: PC hard disk recorder

A PC can also be used as a recorder as an alternative to the commercial off-the-shelf devices, which are usually difficult to upgrade . A distinction is also made here between hardware and software that can record analog and digital input signals.

Analogous

Digital ( DVB )

See also

literature

  • Nico Jurran, Sven Hansen, Carsten FABICH: movie playback devices, DVB-disk receiver with PC Connection. In: c't No. 8, 2006, p. 140

Web links

Commons : Hard disk recorder  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Jurisprudence: I ZR 216/06. In: dejure.org. Retrieved March 18, 2018 .
  2. ↑ Alexander Wegener: Hard disk recorder test. Retrieved March 18, 2018 .