D-VHS

D-VHS is a digital recording format developed by JVC, in collaboration with Hitachi, Matsushita, and Philips. The "D" in D-VHS originally stood for Data VHS, but with the expansion of the format from standard definition to high definition capability, JVC renamed it Digital VHS and uses that designation on its website. It uses the same physical cassette format and recording mechanism as S-VHS (but needs higher quality and more expensive tapes), and is capable of recording and displaying both standard definition and high definition content. The content data format is in MPEG transport stream, the same data format used for most digital television applications. The format was introduced in 1998 and revised in 2012.
==Tape length and speeds==
D-VHS VCRs come with multiple speeds. "HS" is "High Speed", "STD" is "Standard" and "LS" is "Low Speed"; where LS3 and LS5 represent 3 and 5 times the standard length of tape. High-definition content such as 1920x1080 or 1280x720 is typically stored at 28.2 Mbit/s (HS speed) using the MPEG-2 codec or 14.1 Mbit/s (STD speed) using the MPEG-4 AVC codec. Standard-definition content such as 720x576 (720x480) can be stored at bit rates from 14.1 Mbit/s down to 2.8 Mbit/s (STD, LS3, LS5 speeds).
The quality of STD speed is actually superior to the average DVD, since this speed has a much higher bitrate (approximately 14 versus 5 Mbit/s average) and suffers few compression artifacts. The LS3 speed is roughly equal to an amateur DVD with some visible artifacts in high-action scenes (4.7 Mbit/s), and LS5 appears similar to a medium-quality video download (2.8 Mbit/s). JVC's HM-DH40000U and SR-VD400U were the only units to support LS5 recording.
As a result of all these different speeds, the tape labels are a bit confusing for the consumer. D-VHS was originally a standard definition format that recorded at the STD speed. When High Definition recording and HS speed was later introduced, it required twice the amount of tape. For this reason, a DF-240 will record 240 minutes of standard definition, and 240/2 = 120 minutes of high definition. When reviewing the table, note that the digital speeds HS and STD are equivalent to the older analog speeds SP and LP.
Common D-VHS Tape Lengths
Tape Label	Data storage	Tape Length 	Recording Time 	Recording Time	Recording Time 	Recording Time
Tape Label	Data storage	Tape Length 	HS or VHS-SP 	STD or VHS-LP 	LS3 	LS5
DF-240 	25 GB 	248 m (813 ft)	120 min (2 h) 	240 min (4 h) 	720 min (12h) 	1200 min (20 h)
DF-300 	31.7 GB 	314.5 m (1,048 ft) 	150 min (2:30 h)	300 min (5 h) 	900 min (15 h) 	1500 min (25 h)
DF-420 	44 GB 	433 m (1,420 ft) 	210 min (3:30 h)	420 min (7 h) 	1,260 min (21 h)	2100 min (35 h)
DF-480 	50 GB 	500 m (1,640 ft) 	240 min (4 h) 	480 min (8 h) 	1,440 min (24 h)	2400 min (40 h)
==D-Theater==
In 2002, prerecorded D-VHS cassettes were sold under the brand name D-Theater in the US. While D-Theater is a D-VHS tape, it is incompatible with D-VHS decks without the D-Theater logo (which is present on selected JVC decks as well as all Mk. II decks). They provide content in both 720p and 1080i as well as at least one Dolby Digital audio track. Supported film studios for the first generation include 20th Century Fox, Artisan Entertainment, DreamWorks, and Universal Pictures; however, Mk. II tapes are generally distributed by 20th Century Fox, Sony Pictures, Universal Pictures, and Warner Bros. Entertainment, with many studios being distributed by one of the four. D-Theater provides much better audio and video quality than previous formats (VHS and DVD), and there isn't a big difference comparing to Blu-Ray Disc. Region code restrictions are similar to those of DVD.
Most tapes have built-in copy protection mechanism (DTCP, also known as "5c") (copy never) that disables copying via FireWire. HDNet productions and 2929 Entertainment via Magnolia Entertainment did provide some of their original content on D-VHS but without copy protection. Many of the tapes have an introduction by the owner Mark Cuban encouraging the viewer to make copies of the program in order to help distribute them.
==Technical specifications==
===Video===
High-definition content may be stored at HS and STD speeds with up to 2560x1080 pixel resolution at up to 60 (59.94) fields per second. Progressive scan video can be stored with up to 1280x720 pixel resolution at up to 59.94 frames per second. All players are required to process H.262/MPEG-2 Part 2, H.264/MPEG-4 Part 10: AVC (as well as its MVC extension), and SMPTE VC-1; all cassettes must store video in one of these formats.
Resolution	Frame rate 	Aspect ratio
2560×1080 	30i (29.97i)	21:9
2560×1080 	25i 	21:9
1920×1080 	30i (29.97i)	16:9
1920×1080 	25i 	16:9
1800×1080 	30i (29.97i)	5:3
1800×1080 	25i 	5:3
1680×720 	60p (59.94p)	21:9
1680×720 	50p 	21:9
1440×1080 	30i (29.97i)	4:3
1440×1080 	25i 	4:3
1280×720 	60p (59.94p)	16:9
1280×720 	50p 	16:9
1200×720 	60p (59.94p)	5:3
1200×720 	50p 	5:3
960×720 	60p (59.94p)	4:3
960×720 	50p 	4:3
720×480 	30i (29.97i)	4:3 or 16:9
720×576 	25i 	4:3 or 16:9