Talk:DVD

International DVDs

The international DVDs section makes no sense to me. It appears to just be a list of children's channels. What is the purpose of this section? 2603:8080:1E40:2B2A:297E:6D8E:7287:44A5 (talk) 08:43, 5 December 2020 (UTC)

Me neither – it became even more obscure with the added ... channels. I've just removed it. Possibly a mixup with DVB? --Zac67 (talk) 11:52, 7 December 2020 (UTC)

Each DVD sector contains 2418 bytes of data

This article states "Each DVD sector contains 2,418 bytes of data, 2,048 bytes of which are user data.",* but what is the source on that 2418 number? "2,048 bytes of which are user data" seems true - http://index-of.co.uk/Guides/CD%20And%20DVD%20Forensics.pdf. index-of.co.uk/Guides/CD%20And%20DVD%20Forensics.pdf (in http://index-of.co.uk/Guides/) states:

"DVD sectors are composed of data frames on the physical disc. Information other than the 2,048 bytes of user data is not accessible. A DVD data frame contains 4 bytes of ID, 2 bytes of ID Error Correction Code (ECC), 6 bytes of copyright management information, 2,048 bytes of user data, and 4 bytes of Error Detection Code (EDC). Sixteen such data frames are assembled into a single 32K ECC block. It is not possible to access DVD data frames (also called ECC blocks) with consumer DVD drives."

• That's 2064 (4 + 2 + 6 + 2,048 + 4)

https://www.powerdatarecovery.com/cd-dvd-resources/sectors.html states (bold mine):

"Sector 2064 bytes of data is arranged into 12 rows × 172 column array structure, and then a row of 16 data sectors are combined with Reed-Solomon error correction coding, then work out the OCP and the ICP, constitutes a 208 × 182 array error correction block (ECC BLOCK). After encoding, each sector has got an increase of 302 bytes. The newly formed sector is called recording sector. A recording sector is 2366 bytes. Physical sector is to separate the recording sector into two and a half from the middle, each half-frame is added a 26 byte sync code. After the process of 8-16 modulation then a physical sector with sync frame is formed. The concocted physical sector has 4836 bytes which equals to the 2418 bytes before concocting. The data on the physical sector shall form channel data line after line, then recorded onto the DVD discs, it is the real sector on the disc."

Numbers:

• 2418 (26 + 2366 + 26) <--- recording sector plus two 26 byte sync code things
• 1032 (2064/2) <--- half of a data frame
• 2366 (2064+302) <--- recording sector, which is sector+ECC
• 2392 (2366 + 26)
• 946.4 bytes (2366/2.5) <--- 0.4 bytes = 3.2 bits = doesn't work
• 4128 (2064 x 2)

What is "8-16 modulation"? See https://www.powerdatarecovery.com/cd-dvd-resources/8-16-modulation.html:

"DVD has the same principle in reading and writing in data with CD. The pit and land on the disc is to store information. The pit and land are all read as 0. The length of pit and land shall determine the number of 0. The joint of pit and land is read as 1. If the binary numbers works as channel code without concocting, the laser heads will have difficult in reading and writing in data. When coming up with "10101010" the read-write frequency is high, and the bandwidth of the laser circuit shall be wider, while coming up with "00000000", the read-write frequency is very low and the laser beam shall lose the track rail information. Therefore, CD uses EFM, which is 8-14 modulation technology and 3 bits of segregation code to from a 17 bit channel code. DVD is the 8-16 the use of advanced modulation techniques, without separation code, you can not meet up to have more than 10 continuous 0, at least two consecutive 0 requirements. The formation of the channel code is 16 bit to save one digit compared with CD."

I still don't know what 8-16 modulation is.

I'm confused; is a DVD sector 2064 bytes or 2418 bytes or 4836 bytes? Is there such a thing as a physical DVD sector? Or is it all just logical DVD sectors? What is OCP and ICP? Maybe the text (which seems a bit like Engrish) is meant to say "The physical sector is formed by separating the recording sector into two halves, then 26 bytes of sync code is added to each half". 2366/2 = 1183. (1183+26)+(1183+26)=2418. Also "The concocted physical sector has 4836 bytes which equals to the 2418 bytes before concocting." - concocted physical sector before concocting = physical sector, so "2418 bytes before concocting" = "physical sector has 2418 bytes". Further "proof":

"[0026] In order to secure the compatibility with the read-only DVD, the rewritable DVD has a format so that the 2418 B data of one sector of the read-only DVD can be recorded in a user data region of one sector of the rewritable DVD as a unit. This data is called a second data signal." --https://archive.org/details/gov.uspto.patents.application.10769756/10769756-2008-05-02-00007-FOR/page/n3/mode/1up / https://archive.org/stream/gov.uspto.patents.application.10769756/10769756-2008-05-02-00007-FOR_djvu.txt

https://archive.org/details/B-001-001-580/page/n151/mode/2up?q=%222418+bytes%22

Further proof in Table 5.7 Data Storage Characteristics of DVD:

"Modulation: 8/16 (EFMPlus)

Sector size (user data): 2048 bytes

Logical sector size (data unit 1): 2064 (2048 + 12 header + 4 EDC)

Recording sector size (data unit 2): 2366 bytes (2064 + 302 ECC)

Unmodulated physical sector (data unit 3): 2418 bytes (2366 + 52 sync)

Physical sector size: 4836 (2418 x 2 modulation)

Error correction: Reed-Solomon product code (208,192,17) x (182,172,11)

Error correction overhead: 15% (13% of recording sector: 308/2366)

ECC block size: 16 sectors (32678 bytes user data, 37856 bytes total)

Format overhead: 16% (37856/32678)" --https://archive.org/details/dvddemystified00tayl/page/238/mode/2up?q=%222418+bytes%22

What are these data units (data unit 1, data unit 2, and data unit 3)?

*So I think the text should maybe be changed to "Each DVD unmodulated physical sector contains 2,418 bytes of data, 2,048 bytes of which are user data." --User123o987name (talk) 04:02, 4 January 2021 (UTC)

DVD decline NOT explained enough

DVD is very old technology.

When DVD was novelty it could be indeed so:

Within article it is written:

Some analysts suggest that the biggest obstacle to replacing DVD is due to its installed base; a large majority of consumers are satisfied with DVDs.<ref>{{cite journal |url=http://www.businessweek.com/magazine/content/04_16/b3879008_mz001.htm |title=Gates And Ballmer On "Making The Transition" |journal=BusinessWeek |date=2004-04-19 |access-date=2009-08-22 |url-status=dead |archive-url=https://web.archive.org/web/20090826072638/http://www.businessweek.com/magazine/content/04_16/b3879008_mz001.htm |archive-date=2009-08-26 }}</ref>

But nowadays there is more and more Bigger TV screens in first world countries, and old quality and its flaws are seen more and more clear.

Today even mobile phones have capacity to capture video film in 4k.

And for most purpose like talking heads programming it looks better than DVD.

Within article it is written:

DVDs are also facing competition from video on demand services.<ref>{{cite web|url=http://electronics.howstuffworks.com/are-dvds-becoming-obsolete.htm|title=Are DVDs becoming obsolete?|date=1 November 2014|website=Electronics.howstuffworks.com|access-date=30 December 2016|archive-url=https://web.archive.org/web/20150405065830/http://electronics.howstuffworks.com/are-dvds-becoming-obsolete.htm|archive-date=April 5, 2015|url-status=live}}</ref><ref>{{cite web|url=https://www.amazon.com/forum/movie?_encoding=UTF8&cdForum=Fx2E577OZX17PPI&cdThread=TxQZAH1GWRJW8V|title=Amazon.com: Customer Discussions: When will DVDs be obsolete?|website=Amazon.com|access-date=30 December 2016|archive-url=https://web.archive.org/web/20160305105306/http://www.amazon.com/forum/movie?_encoding=UTF8&cdForum=Fx2E577OZX17PPI&cdThread=TxQZAH1GWRJW8V|archive-date=March 5, 2016|url-status=live}}</ref><ref>{{cite web|url=http://screencrush.com/dvd-sales-decline-study/|title=Is the DVD Becoming Obsolete?|publisher=ScreenCrush|last=Romano|first=Nick|access-date=30 December 2016|archive-url=https://web.archive.org/web/20150412025847/http://screencrush.com/dvd-sales-decline-study/|archive-date=April 12, 2015|url-status=live}}</ref><ref>{{cite web|url=http://www.cinemablend.com/new/DVD-Going-Way-VHS-2016-43349.html|title=DVD Going The Way Of VHS In 2016 – CINEMABLEND|date=6 June 2014|website=Cinemablend.com|access-date=30 December 2016|archive-url=https://web.archive.org/web/20150412082730/http://www.cinemablend.com/new/DVD-Going-Way-VHS-2016-43349.html|archive-date=April 12, 2015|url-status=live}}</ref> With increasing numbers of homes having high speed Internet connections, many people now have the option to either rent or buy video from an online service, and view it by streaming it directly from that service's servers, meaning they no longer need any form of permanent storage media for video at all. By 2017, digital streaming services had overtaken the sales of DVDs and Blu-rays for the first time.<ref>{{cite web|url=https://www.theguardian.com/media/2017/jan/05/film-and-tv-streaming-and-downloads-overtake-dvd-sales-for-first-time-netflix-amazon-uk|title=Film and TV streaming and downloads overtake DVD sales for first time|first=Mark|last=Sweney|date=5 January 2017|access-date=28 October 2017|website=Theguardian.com|archive-url=https://web.archive.org/web/20180103030245/https://www.theguardian.com/media/2017/jan/05/film-and-tv-streaming-and-downloads-overtake-dvd-sales-for-first-time-netflix-amazon-uk|archive-date=January 3, 2018|url-status=live}}</ref>

Yes indeed even YT in FHD and 60HZ of fps can have better technical than DVD.

However I would like to mention DVD is competing not only against VOD, but also against nowadays ordinary wide spread Free To Air DTTV which is also in HD, and when it is using better next generation of video codecs: MPEG-4 or HEVC/H.265 it is not worse quality than DVD (if not better).

When DVD was novelty it was proclaim that quality would endure 100years.

And it could be so in technical terms: optical disc can store information for a long time, but DVD no longer offers superior quality, nor next generation of optical disc are of superior quality.

When peoples were buying DVD, it was superior quality, so they could store optical disc, that they would come back to them in their old age.

However Today general population knows (assumes) if they would buy BluRay 4k UHD it will be in outdated quality for their old age due to supposed wide spread of 8K resolution Screens and materials.

It is not my original research.

But is is very obvious to me as reality in first world countries. (It can be different in third world countries).

You do not need to be Sherlock in order to see that it can be hard to expect to sell for money optical disc with material of lower technical quality than: Free To Air DTTV, (I guess such inadequate business model has a name in economy) and you can not expect people will believe in storing such poor quality for later usage:
for years to come (or for ages / centuries to come). (I guess such inadequate business model has also a name in economy)

DVD is very very old technology, and article on this subject should be revisited.

I do not expect that my points here will be incorporated into article.

I have just used talk section according to rules:

Proposition of a change of the outdated section of the article. 46.187.202.138 (talk) 16:56, February 3, 2021 (UTC)

Uncited material in need of citations

I am moving the following uncited material here until it can be properly supported with inline citations of reliable, secondary sources, per WP:V, WP:NOR, WP:CS, WP:NOR, WP:IRS, WP:PSTS, et al. This diff shows where it was in the article. Nightscream (talk) 20:44, 3 September 2022 (UTC)

Extended content

History Development and launch Comparison of several forms of disk storage showing tracks (tracks not to scale); green denotes start and red denotes end. * Some CD-R(W) and DVD-R(W)/DVD+R(W) recorders operate in ZCLV, CAA or CAV modes, but most work in constant linear velocity (CLV) mode. Kees Schouhamer Immink received a personal technical Emmy award for his contributions to DVD and Blu-ray disc. There were several formats developed for recording video on optical discs before the DVD. Optical recording technology was invented by David Paul Gregg and James Russell in 1963 and first patented in 1968. A consumer optical disc data format known as the LaserDisc was developed in the United States, and first came to market in Atlanta, Georgia in December 1978. It used much larger discs than the later formats. Due to the high cost of players and discs, consumer adoption of the LaserDisc was very low in both North America and Europe, and was not widely used anywhere outside Japan and the more affluent areas of Southeast Asia, such as Hong Kong, Singapore, Malaysia and Taiwan. The Super Density logo would later be reused in Secure Digital. Representatives from the SD camp asked IBM for advice on the file system to use for their disc, and sought support for their format for storing computer data. Alan E. Bell, a researcher from IBM's Almaden Research Center, got that request, and also learned of the MMCD development project. Wary of being caught in a repeat of the costly videotape format war between VHS and Betamax in the 1980s, he convened a group of computer industry experts, including representatives from Apple, Microsoft, Sun Microsystems, Dell, and many others. This group was referred to as the Technical Working Group, or TWG. ...and EFMPlus modulation designed by Kees Schouhamer Immink. Shortly after the format's finalization, talks began in mid-December 1995 on how to distribute the format at retail. Adoption They embraced DVD as it produced higher quality video and sound, provided superior data lifespan, and could be interactive. Interactivity on LaserDiscs had proven desirable to consumers, especially collectors. When LaserDisc prices dropped from approximately $100 per disc to $20 per disc at retail, this luxury feature became available for mass consumption. Simultaneously, the movie studios decided to change their home entertainment release model from a rental model to a for purchase model, and large numbers of DVDs were sold. At the same time, a demand for interactive design talent and services was created. Movies in the past had uniquely designed title sequences. Suddenly every movie being released required information architecture and interactive design components that matched the film's tone and were at the quality level that Hollywood demanded for its product. DVD as a format had two qualities at the time that were not available in any other interactive medium: enough capacity and speed to provide high quality, full motion video and sound, and low cost delivery mechanism provided by consumer products retailers. Retailers would quickly move to sell their players for under $200, and eventually for under $50 at retail. In addition, the medium itself was small enough and light enough to mail using general first class postage. Almost overnight, this created a new business opportunity and model for business innovators to re-invent the home entertainment distribution model. It also gave companies an inexpensive way to provide business and product information on full motion video through direct mail. Specifications Additionally the DVD6C patent pool holds patents used by DVD drives and discs. The capacity of DVDs is conventionally stated in gigabytes (GB), with the decimal definition of this term such that 1 GB = 109 bytes. Discs with multiple layers Like other optical disc formats before it, a basic DVD disc—known as DVD-5 in the DVD Books, while called Type A in the ISO standard—contains a single data layer readable from only one side. However, the DVD format also includes specifications for three types of discs with additional recorded layers, expanding disc data capacity beyond the 4.7 GB of DVD-5 while maintaining the same physical disc size. Double-sided discs Double-sided discs identify the sides as A and B. The disc structure lacks the dummy layer where identifying labels are printed on single-sided discs, so information such as title and side are printed on one or both sides of the non-data clamping zone at the center of the disc. DVD-10 discs fell out of favor because, unlike dual-layer discs, they require users to manually flip them to access the complete content (a relatively egregious scenario for DVD movies) while offering only a negligible benefit in capacity. Additionally, without a non-data side, they proved harder to handle and store. Dual-layer discs Dual-layer discs also employ a second recorded layer, however both are readable from the same side (and unreadable from the other). These DVD-9 discs (Type C in ISO) nearly double the capacity of DVD-5 discs to a nominal 8.5 GB, but fall below the overall capacity of DVD-10 discs due to differences in the physical data structure of the additional recorded layer. However, the advantage of not needing to flip the disc to access the complete recorded data – permitting a nearly contiguous experience for A/V content whose size exceeds the capacity of a single layer – proved a more favorable option for mass-produced DVD movies. Most dual-layer discs are mastered with layer 0 starting at the inside diameter and proceeding outward—as is the case for most optical media, regardless of layer count—while Layer 1 starts at the absolute outside diameter and proceeds inward. Additionally, data tracks are spiraled such that the disc rotates the same direction to read both layers. DVD video DL discs can be mastered slightly differently: a single media stream can be divided between the layers such that layer 1 starts at the same diameter that layer 0 finishes. This modification reduces the visible layer transition pause because after refocusing, the laser remains in place rather than losing additional time traversing the remaining disc diameter. DVD-9 was the first commercially successful implementation of such technology. Combinations of the above DVD-18 discs (Type D in ISO) effectively combines the DVD-9 and DVD-10 disc types by containing four recorded data layers (allocated as two sets of layers 0 and 1) such that only one layer set is accessible from either side of the disc. These discs provide a total nominal capacity of 17.0 GB, with 8.5 GB per side. This format was initially used for television series released on DVD (like the first releases of Miami Vice and Quantum Leap), but was eventually abandoned in favor of single sided discs for reissues. DVD recordable and rewritable Although most current DVD writers can write in both the DVD+R/RW and DVD-R/RW formats (usually denoted by "DVD±RW" or the existence of both the DVD Forum logo and the DVD+RW Alliance logo), the "plus" and the "dash" formats use different writing specifications. Most DVD hardware plays both kinds of discs, though older models can have trouble with the "plus" variants. Some early DVD players would cause damage to DVD±R/RW/DL when attempting to read them. The form of the spiral groove that makes up the structure of a recordable DVD encodes unalterable identification data known as Media Identification Code (MID). The MID contains data such as the manufacturer and model, byte capacity, allowed data rates (also known as speed), etc.. Dual-layer recording Many current DVD recorders support dual-layer technology, and while the costs became comparable to single-layer burners over time, blank dual-layer media has remained more expensive than single-layer media. Capacity The basic types of DVD (12 cm diameter, single-sided or homogeneous double-sided) are referred to by a rough approximation of their capacity in gigabytes. In draft versions of the specification, DVD-5 indeed held five gigabytes, but some parameters were changed later on as explained above, so the capacity decreased. Other formats, those with 8 cm diameter and hybrid variants, acquired similar numeric names with even larger deviation. The 12 cm type is a standard DVD, and the 8 cm variety is known as a MiniDVD. These are the same sizes as a standard CD and a mini-CD, respectively. The capacity by surface area (MiB/cm2) varies from 6.92 MiB/cm2 in the DVD-1 to 18.0 MB/cm2 in the DVD-18. Each DVD sector contains 2,418 bytes of data, 2,048 bytes of which are user data. There is a small difference in storage space between + and - (hyphen) formats: Scan of a DVD-R; the "a" portion has been recorded on while the "b" portion has not. It may be less obvious in CD-Rs and BD-Rs. Laser and optics Comparison of various optical storage media All three common optical disc media (Compact disc, DVD, and Blu-ray) use light from laser diodes, for its spectral purity and ability to be focused precisely. DVD uses light of 650 nm wavelength (red), as opposed to 780 nm (far-red, commonly called infrared) for CD. This shorter wavelength allows a smaller pit on the media surface compared to CDs (0.74 µm for DVD versus 1.6 µm for CD), accounting in part for DVD's increased storage capacity. In comparison, Blu-ray Disc, the successor to the DVD format, uses a wavelength of 405 nm (violet), and one dual-layer disc has a 50 GB storage capacity. Transfer rates However, in practice, discs should never be spun at their highest possible speed, to allow for a safety margin and for slight differences between discs, and to prevent material fatigue from the physical stress. Errors on DVDs are measured as: PIE — Parity Inner Error PIF — Parity Inner Failure POE — Parity Outer Error POF — Parity Outer Failure A higher rate of errors may indicate a lower media quality, deteriorating media, scratches and dirt on the surface, and/or a malfunctioning DVD writer. PI errors, PI failures and PO errors are correctable, while a PO failure indicates a CRC error, one 2048 byte block (or sector) of data loss, a result of too many consecutive smaller errors. Additional parameters that can be measured are laser beam focus errors, tracking errors, jitter and beta errors (inconsistencies in lengths of lands and pits). Security The Content Scramble System (CSS) is a digital rights management (DRM) and encryption system employed on almost all commercially produced DVD-video discs. CSS utilizes a proprietary 40-bit stream cipher algorithm. The system was introduced around 1996 and was first compromised in 1999. While most CSS-decrypting software is used to play DVD videos, other pieces of software (such as DVD Decrypter, AnyDVD, DVD43, Smartripper, and DVD Shrink) can copy a DVD to a hard drive and remove Macrovision, CSS encryption, region codes and user operation prohibition. Consumer restrictions The rise of filesharing has prompted many copyright holders to display notices on DVD packaging or displayed on screen when the content is played that warn consumers of the illegality of certain uses of the DVD. It is commonplace to include a 90-second advertisement warning that most forms of copying the contents are illegal. Many DVDs prevent skipping past or fast-forwarding through this warning. Arrangements for renting and lending differ by geography. In the U.S., the right to re-sell, rent, or lend out bought DVDs is protected by the first-sale doctrine under the Copyright Act of 1976. In Europe, rental and lending rights are more limited, under a 1992 European Directive that gives copyright holders broader powers to restrict the commercial renting and public lending of DVD copies of their work. DVD-Audio Main article: DVD-Audio DVD-Audio is a format for delivering high fidelity audio content on a DVD. It offers many channel configuration options (from mono to 5.1 surround sound) at various sampling frequencies (up to 24-bits/192 kHz versus CDDA's 16-bits/44.1 kHz). Compared with the CD format, the much higher-capacity DVD format enables the inclusion of considerably more music (with respect to total running time and quantity of songs) or far higher audio quality (reflected by higher sampling rates, greater sample resolution and additional channels for spatial sound reproduction). DVD-Audio briefly formed a niche market, probably due to the very sort of format war with rival standard SACD that DVD-Video avoided. Security Main article: Content Protection for Recordable Media DVD-Audio discs employ a DRM mechanism, called Content Protection for Prerecorded Media (CPPM), developed by the 4C group (IBM, Intel, Matsushita, and Toshiba). Although CPPM was supposed to be much harder to crack than a DVD-Video CSS, it too was eventually cracked, in 2007, with the release of the dvdcpxm tool. The subsequent release of the libdvdcpxm library (based on dvdcpxm) allowed for the development of open source DVD-Audio players and ripping software. As a result, making 1:1 copies of DVD-Audio discs is now possible with relative ease, much like DVD-Video discs. Successors and decline The DVD succeeded because it offered a compelling alternative to VHS. In addition, the uniform media size lets manufacturers make Blu-ray players (and HD DVD players) backward-compatible, so they can play older DVDs. This stands in contrast to the change from vinyl to CD, and from tape to DVD, which involved a complete change in physical medium. As of 2019 it is still commonplace for studios to issue major releases in "combo pack" format, including both a DVD and a Blu-ray disc (as well as a digital copy). Also, some multi-disc sets use Blu-ray for the main feature, but DVDs for supplementary features (examples of this include the Harry Potter "Ultimate Edition" collections, the 2009 re-release of the 1967 The Prisoner TV series, and a 2007 collection related to Blade Runner). Another reason cited (July 2011) for the slower transition to Blu-ray from DVD is the necessity of and confusion over "firmware updates" and needing an internet connection to perform updates. This situation is similar to the changeover from 78 rpm shellac recordings to 45 rpm and 33⅓ rpm vinyl recordings. Because the new and old media were virtually the same (a disc on a turntable, played by a needle), phonograph player manufacturers continued to include the ability to play 78s for decades after the format was discontinued. However, What We Left Behind included small amounts of remastered Deep Space Nine footage.

Sucessors and Decline Section Needs Update

The section uses data from 2011. InjectableBacon (talk) 09:05, 31 December 2022 (UTC)

probaly company dvd roms they make not cheep crap ones sells out here people need make videos again have them for hire at the video shops again people videos not dvds 101.188.189.73 (talk) 22:53, 15 June 2023 (UTC)