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camcorders are usually offered with either 50 Hz or 60 Hz scanning rate depending on a region. Some models, like Canon XH-A1/G1 and third-generation Sony models such as HVR-S270, HVR-Z5 and HVR-Z7, can be made switchable for "world" capability.[32] Some JVC ProHD products like the GY-HD250U are world-capable out of the box.[33] HDV is related to XDCAM and to TOD families of recording formats, which use the same video encoding — MPEG-2. In particular, 1080-line HDV is equivalent to 25 Mbit/s SP recording mode of XDCAM and to 1440CBR recording mode of TOD. [edit] Recording media MiniDV cassettes for DV and HDV recording HDV remains predominantly a tape-based format despite various tapeless recording solutions available on the market. The HDV consortium allows using the HDV trademarks only for products that incorporate a tape drive that can record and play video cassette compliant to the HDV format.[3] [edit] Magnetic tape Most HDV camcorders use MiniDV cassettes also known as "small" DV cassettes. The Sony HVR-S270 shoulder-mount camcorder is capable of recording both onto "small" and "large" cassettes. Because HDV has the same data rate as DV, recording time is the same as DV Standard Play. Unlike DV, HDV does not offer Long Play speed. A standard MiniDV cassette provides one hour of recording. By using cassettes with longer and thinner tape it is possible to record up to 80 minutes onto one MiniDV cassette, though usage of such tape is not recommended. Large DV cassette loaded with longer tape can deliver up to 4.5 hours of recording time. Tape manufacturers also offer MiniDV cassettes specifically for HDV recording. Such cassettes have the same Metal Evaporate (ME) formulation as normal DV cassettes, but are manufactured with smaller tolerances. These cassettes are claimed to have reduced drop-out rate compared to standard DV cassettes. Usage of such cassettes is not required by HDV specification. [edit] File-based media Type I CompactFlash card Since HDV was introduced, tapeless — or file-based — video recording formats such as DVCPRO P2, XDCAM and AVCHD have gained broad acceptance. The trend towards tapeless workflow was accelerated with increased capacity and reduced cost of non-linear storage solutions like hard disk drives, optical discs and solid-state memory. Recognizing the need for faster workflow, JVC, Sony and other manufacturers offer on-camera recording units, which convert an HDV camcorder into a hybrid system capable of recording both onto tape and onto file-based media. These recorders connect to a camcorder via FireWire and do not recompress HDV video, offering exactly the same image quality as if video were recorded on tape. JVC offers two FireStore recorders made by Focus Enhancements: the HDD-based DR-HD100[34] and MR-HD100[35] on-camera recorders; it also offers the SxS-based KA-MR100G[36] recorder. Canon offers Focus Enhancements FS-CF and FS-CF Pro models, which record onto CompactFlash memory cards.[37] Sony offers the HDD-based HVR-DR60[38] and the CompactFlash-based HVR-MRC1K[39] recorders. Recording time depends on capacity of media used. In particular, a 32 GB CompactFlash card is good for 72 minutes of HDV video. The HVR-DR60 can fit over two hours of high definition video, while the FireStore models with 100 GB disk drive can store almost four hours of footage. File-based recorders are invaluable for continuous recording that extends one hour. [edit] Use in broadcast television HDV is accepted with varying restrictions for broadcast TV use. It has been used for shows like Deadliest Catch and MythBusters, and was used in the TV series JAG for scenes where larger HD cameras would have been impractical. The BBC has adopted HDV cameras as replacement for DV camcorders to produce widescreen standard definition content.[40] Acceptability of HDV footage for international HD programming is limited to no more than 25% of programming content if the contributed material meets one of the five "technical exemption" categories: Artistic interest, Historical interest, Actuality material, Early television and cinema or Home videos.[41] Restrictions for domestic HD programming are less stringent. The Discovery HD Theater accepts content sourced from 1080-line HDV camcorders, but limits it to 15% of a whole program. Producers wishing to use HDV are required to submit an approved postproduction path outlining their handling of the footage in the editing process.[6] The Discovery Channel HD simulcast has fewer or no guidelines and accepts a mix of XDCAM HD, HDV and AVCHD for the length of a program. For example, Discovery Channel aired 911: The Bronx, a six-episode reality series set in a hospital and shot with HDV cameras.[42][43] Several episodes of Survivorman were shot with the Sony HVR-Z1U and HDR-HC3 camcorders.[44] The Discovery Channel International uses rating system that defines Gold, Silver and Bronze acquisition and delivery levels. Depending on particular camera make and model and on post-production process, HDV footage can be rated either Silver or Bronze HD, or widescreen SD.[45] In particular, some users consider Canon HDV camcorders to deliver the best-looking image with the least amount of compression artifacts among the models having 25 Mbit/s MPEG-2 HD codec.[22][46] The PBS accepts HDV for widescreen programming acquisition and to a limited extent for use in HD programs.[47] PBS may allow usage of "less than full broadcast quality equipment" if compression artifacts are "not obvious when viewed on an HDTV monitor".[48] For example, the Art Wolfe's TV series Travels to the Edge was produced for PBS in HDV format using Canon XL-H1 camcorders.[49] The Travel Channel HD eagerly accepts HDV footage. For example, highly acclaimed Anthony Bourdain's No Reservations program has been produced with Sony HDV camcorders: HVR-V1U for earlier shows and HVR-Z7U for newer shows.[50] Bizarre Foods with Andrew Zimmern and its follow-up Bizarre World are shot with Sony HDV cameras as well.[51] Madventures was shot with the Sony EX1 XDCAM EX camera paired with the Sony HVR-A1U HDV camcorder.[52] Guiding Light, the longest-running soap opera in production in television and radio history, broke away from traditional three-sided sets and pedestal-style cameras in 2008, choosing the handheld Canon XH-G1 for shooting on practical locations.[53] [edit] Editing Because HDV video is recorded in digital form, original content can be copied onto another tape or captured to a computer for editing without quality degradation. Depending on capturing software and computer's file system, either a whole tape is captured into one contiguous file, or the video is split in smaller 4 GB or 2 GB segments, or a separate file is created for each take. The way files are named depends on capturing software. Some systems convert HDV video into proprietary intermediate format on the fly while capturing, so original format is not preserved. HDV footage can be natively edited by most non-linear editors, with real-time playback being possible on modern mainstream personal computers. Slower computers may exhibit reduced performance compared to other formats such as DV because of high resolution and interframe compression of HDV video. Editing performance can be improved by converting HDV to intermediate format prior to editing. These include various Cineform products, Edius HQ, Avid DNxHD, Apple Intermediate Codec and Apple ProRes 422, among others. Usage of an intermediate codec adds one more generation to the video, potentially degrading its quality. On another hand, an intermediate codec can reduce blockiness and fix other issues in the original video, like interlaced chroma in progressive recordings. Depending on NLE, it is possible to avoid generation losses by editing native HDV video using straight cuts only and saving it back to HDV. [edit] Distributing HDV video can be recorded or printed back to tape. Such tapes are often accepted by local television stations, though many organizations prefer the submissions to be delivered in higher-end format like Digital Betacam, HDCAM or D5 HD.[6][48] It is also possible to record M2TS file to any media that offers enough capacity, like a DVD disc, external HDD drive or a memory card. For consumer use, HDV-sourced video can be delivered on a Blu-ray Disc without re-encoding, can be converted to AVCHD and delivered on an AVCHD disc, or can be downconverted to DVD-Video. [edit] Products [edit] Canon Canon XL-H1 Canon HV30 Canon entered the HDV market in September 2005, with the Canon XL H1, a professional-oriented modular camera system with interchangeable lenses, HD-SDI output, and three 1440 × 1080 ⅓" CCDs. This was the first HDV camcorder to allow 1080-line native progressive recording. In July 2006, Canon announced the handheld XH A1/XH G1 models, which use the same sensor as the XL-H1. Both models share the same body and most of the features, with the XH G1 geared towards professional multi-camera production and including connections for HD-SDI/SD-SDI Out, genlock, and time code. Later in the same year, Canon introduced the consumer-oriented Canon HV10, a compact unit with a single 2.76 megapixel CMOS sensor. The camera recorded interlaced video only. In April 2007 Canon released the HV20 which used the same sensor and internal processor as the HV10, had a larger lens and more conventional layout. This was the first consumer HDV camcorder that featured progressive shooting modes in addition to native interlaced recording. Progressive-scan video was recorded within interlaced container to remain compatible with consumer level editing suites. The version for 50 Hz market offered PF25 mode, which utilized Progressive segmented Frame technique, while the 60 Hz variant featured PF24 mode, which utilized 2-3 pulldown scheme. The HV30, released in 2008, was a minor update of the HV20. The body color has been changed from silver to black, the LCD screen has been improved, and the 60 Hz variant implemented PsF-like PF30 mode. In 2009 Canon released the HV40. Its 50 Hz variant was practically identical to the HV30, while the 60 Hz variant became the fs, like Borland's Turbo Debugger, D86 (by Alan J. Cox) and Microsoft's CodeView could work in a dual monitor setup. Either Turbo Debugger or CodeView could be used to debug Windows. There were also DOS device drivers such as ox.sys, which implemented a serial interface simulation on the MDA display and, for example, allowed the user to receive crash messages from debugging versions of Windows without using an actual serial terminal. It is also possible to use the "MODE MONO" command at the DOS prompt to redirect the output to the monochrome display. When a Monochrome Display Adapter was not present it was possible to use the 0xB000 – 0xB7FF address space as additional memory for other programs (for example by adding the line "DEVICE=EMM386.EXE I=B000-B7FF" into config.sys, this memory would be made available to programs that can be "loaded high" – loaded into high memory.)The VGA color system is backwards compatible with the EGA and CGA adapters, and adds another level of configuration on top of that. CGA was able to display up to 16 colors, and EGA extended this by allowing each of the 16 colors to be chosen from a 64-color palette (these 64 colors are made up of two bits each for red, green and blue: two bits × three channels = six bits = 64 different values). VGA further extends this scheme by increasing the EGA palette from 64 entries to 256 entries. Two more blocks of 64 colors with progressively darker shades were added, along with 8 "blank" entries that were set to black.[12][dubious – discuss] In addition to the extended palette, each of the 256 entries could be assigned an arbitrary color value through the VGA DAC. The EGA BIOS only allowed 2 bits per channel to represent each entry, while VGA allowed 6 bits to represent the intensity of each of the three primaries (red, blue and green). This provided a total of 64 different intensity levels for red, green and blue, resulting in 262,144 possible colors, any 256 of which could be assigned to the palette (and in turn out of those 256, any 16 of them could be displayed in CGA video modes). This method allowed new VGA colors to be used in EGA and CGA graphics modes, providing one remembered how the different palette systems are laid together. To set the text color to very dark red in text mode, for instance, it will need to be set to one of the CGA colors (for example, the default color, #7: light grey.) This color then maps to one in the EGA palette—in the case of CGA color 7, it maps to EGA palette entry 42. The VGA DAC must then be configured to change color 42 to dark red, and then immediately anything displayed on the screen in light-grey (CGA color 7) will become dark red. This feature was often used in 256-color VGA DOS games when they first loaded, by smoothly fading out the text screen to black. (The game Descent, from 1995, is an example.) While CGA and EGA-compatible modes only allowed 16 colors to be displayed at any one time, other VGA modes, such as the widely used mode 13h, allowed all 256 palette entries to be displayed on the screen at the same time, and so in these modes any 256 colors could be shown out of the 262,144 colors available.