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On 1 December 2023, it was proposed that this article be moved to DV (video). The result of the discussion was Moved to DV (video format). |
The article states that unlocked audio may cause a one-third frame sync offset. I'm not sure that this is correct - what unlocked audio means is that the audio sampling clock isn't phase locked to the video frame rate, so the samples per frame may vary very fractionally.
I have been editing DV for ten years, including match editing recovered programme material together from various tape and disk sources, and I have never seen a sync offset of more than a couple of samples. —Preceding unsigned comment added by 91.84.80.40 (talk) 21:11, 2 February 2009 (UTC)
Is it appropriate to put a link to the software that is mentioned in the article? The article mentions software which allows a MiniDV camcorder to be used as a data storage device but doesn't give the name or a link; this seems foolish. If we're going to mention the existence of the software, we might as well give the name.
The only software I could find which meets the description is called 'DV Backup,' it's $45 shareware, and it's from http://www.coolatoola.com/.
I've seen some mention of DV types 1 and 2. Could something about this possibly be mentioned in the article? Certain software apps only support type-2. — SimonEast 08:39, 15 Oct 2004 (UTC)
I believe the last line of this article is flawed; "In 1993, Sony, JVC, Canon, and Sharp have come up with the HDV standard for high-definition camcorders." I don't believe it should say "In 1993, Sony, JVC, Canon, and Sharp have come up with the Hi8 standard for 8MM camcorders."
The Color Sampling section should probably be reworked into just advantages/disadvantages, since it's halfway there already.
Doesnt the DVCPRO also have a separate track for timecode, this is missing in the article? In the article only the extra audio cue track is mentioned.
At the beginning of the article, DV is referred to as a "video format", then down below, as a "codec". Is this poor terminology, or is the codec a sub part of the larger format? As far as I can tell, there are codecs, and there are tape sizes/formats. The two are technologically distinct, but in implementation, each tape has a given format that it uses, and there are few (no?) cases where two cameras use the same type of tape but write a different codec. Datarate is a whole other bag of chips. Do DVC pro 50 and DVC pro HD really use the exact same codec, but with a doubled data rate? What hardware at each end of the process supports these things?
--Johnjosephbachir 01:22, 5 Dec 2004 (UTC)
The link to minidv just goes back to itself, I'm removing it, someone please tell me if I'm doing something wrong. Szabo 23:53, 9 Dec 2004 (UTC)
At the end of the DVCPRO section, it says:
"Willians Terence Hills is the very important videoast the USA. In América Latin the brazilians e the mexicans are the more importants videomaker, the name of the José Patrício Neto in Brazil (Maranhão) and Roberto Mendez in Mexico are stars."
What the hell is this about? Some sort of database error?
Does anyone know if there are any reader/writers that allow people to read/write to/from dv and/or minidv tapes on a computer without using a camera? --4.245.7.3 07:18, 20 May 2005 (UTC)
Using the camera as a deck is not reccomended by professionals, due to the excess wear it generates on the heads, but it is unavoidable if you can't afford a professional deck. --202.170.45.13 11:56, 19 June 2007 (UTC)
what's the video resolution of ordinary mini dv recordings? how does it compare to DVD? RustyCale 13:27, 22 May 2005 (UTC)
I would like to see something added about the history and development of the DV format. It also should be mentioned (if I am correct in this) that the Digital-8mm format uses the DV codec. —Preceding unsigned comment added by LexieM (talk • contribs)
It would be nice to see information about what company/companies/consortium originally created the format, since the article seems to say that ISO standardization came after original "Blue Book" development. —SudoMonas 05:02, 14 August 2006 (UTC)
I was involved in the standardisation. It started in 1990 as a cooperation between Philips, Thomson, Matsushita and JVC. Later on Sony joined. When the standard was more or less agreed between these 5 companiers all other were invited to join the DV consortium. There were many discussion on how to add new features that were not present in existing systems. In the end some features that were realised were: adding meta data (subcode),high speed forward/reverse whilst being able to read the metadata, memory-in-cassette to read metadata without inserting the cassette in a player, post-edit of audio tracks, etc.
Does anyone know if/when the tapes fatigue? GChriss 22:35, 18 March 2006 (UTC)
I guess the real question is, can the tapes be used over again without a noticable degredation in quality. If so, how many times? 205.157.110.11 01:50, 2 November 2006 (UTC)
This is also one of the more practical differences between small format MiniDV tape and Medium format DVCAM tapes. DVCAM tapes seem to be built much more robustly and tend to lastlonger
I had a minidv tape I reused roughly 8-10 times. The last time I went to record something on it, the camera's head (a Canon XL1) took a slice out of the magnetic material. Holding the tape up to light, I was able to identify where it happened by the clear streak across the tape. This obviously left the camera unable to play or record anything until I cleaned the heads. So, I would say it's ok to use a tape a few times but no more. Brock1912 (talk) 07:16, 10 April 2011 (UTC)
This item intruiges me: "MiniDV tapes can be played with a cassette-adaptor.". Now I must have missed something. I believed the DVC Pro tapes are based on Betacam shells (and therefore on domestic Betamax) which is a 1/2" tape format. So what kind of adaptor could allow a miniDV tape to work in a 1/2" mechanism? This can't be. So either I'm wrong about the shell size of DVC Pro, or this adaptor is a non-starter. Explanation welcome! Colin99 17:45, 4 July 2006 (UTC)
You are indeed wrong about the shell size. DVCPRO cassettes use the same shell design as DVCam, but DVCPRO aren't available in the 'mini' size, hence the need for an adaptor if you want to play 'mini' cassetees in a DVCPRO VTR. One cassette adaptor model is the Panasonic AJ-CS455: http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=227684&is=REG
Unlike DVD,VCD, etc., there is no resolution data included in the DV (miniDV) page. I am really an amateur. I noticed and read your technical discussion on DV resolution, but I am still in the mist - Is there simply a DV resolution of ???x??? can be quoted? or how can we compare the resolution between DVD and DV ?--Chan w 06:16, 9 March 2007 (UTC)
720x480 is for 525 line - 30 frame per second systems (as used in NTSC)and 720x576 for 625 line - 25 frame systems (as used in PAL, SECAM)
DV doesn't have a defined resolution. The DV format defines the coding parameters and recording format, not camera performance. The 720 is not the resolution - it is the sampling rate. The resolution is lower than this, and will be limited by the optics, sensor and processing before it gets to the output coding.
The article says that DCT intraframe compression performs marginally better than MJPEG. But how does "DCT intraframe" differ from MJPEG? As I recall, a MPJEG stream simply contains JPEG images to be shown sequentially (there are only I-frames). JPEG images are compressed using DCT (and Huffman compression). So another description for MJPEG would be "DCT intraframe compression". The writer of the compression section has us believe that MJPEG differs from the compression used on DV tapes. Can anyone explain the difference between the two?
I believe DV has one quantisation table per macroblock, but don't quote me.
The article wrongly states that gamma (or power function) correction of (1/0.45) is used. The gamma correction applied is actually 0.45. (1/0.45), more correctly stated as 2.2, is the assumed gamma of the monitor.
The article says says
"DVCPRO HD encodes using 4:2:2 color sampling. DVCPRO HD prefilters the 720p image from the DSP to a recorded size of 960x720, and 1080i is prefiltered to 1280x1080 for 59.94i and 1440x1080 for 50i."
If it is pre-filtered to this resolution, then it CANNOT be called 4:2:2. The 4 in the 4:2:2 means full resolution. When Sony downsample to 1440:480:480 for HDCam they accurately call their system 3:1:1.
"The data is now compressed using one of several algorithms including Discrete Cosine Transform (DCT), Adaptive Quantization (AQ), and Variable Length Coding (VLC)."
DCT and AQ are not forms of compression as stated - neither of these processes compresses. They are pre-compression processing, enabling the VC (and RLE which the author has omitted) to work efficiently. A file having DCT and AQ applied will not be any smaller than the original.
According to Keith Jack (Video Demystified - 5th Edition 2007 ISBN:978-0-7506-8395-1) DV has a special way of applying DCT to interlaced frames; each pair of (buffered) fields is compared, if they are 'similar' (low motion shift) standard 8-8-DCT is applied to the whole frame (both fields), but if the fields are "not similar" (high motion shift), "2-4-8-DCT" is applied to each field separately. The type of DCT block is recorded in the DC coefficient area using 1 bit. Sounds to me like this frame-or-field-DCT threshold will have a significant impact on interlacing artifacts ? Redbobblehat (talk) 15:39, 3 September 2008 (UTC)
According to Jack (op cit.) each DCT block covers 8 vertical x 8 horizontal samples in one of the Y'CbCr channels, and each DCT macroblock is made up of a number of DCT blocks. Due to chroma subsampling, each 4:2:0 or 4:1:1 macroblock consists of 4 luma plus 2 chroma DCT blocks. For 4:2:2 each macroblock has 2 luma and 2 chroma DCT blocks. The 4:2:2 macroblock has a 2:1 horizontal aspect ratio (covering 8x16 pixels), whereas the 4:2:0 are "square" (16x16 pixels) format and 4:1:1 has a (mostly) 4:1 horizontal AR (8x32 pixels). Redbobblehat (talk) 15:39, 3 September 2008 (UTC)
According to Jack (op cit.) each superblock consists of 27 macroblocks. So:
Redbobblehat (talk) 15:39, 3 September 2008 (UTC)
The photo leading this article is not good. Can't someone offer a clearer shot, without a kitschy tablecloth?
There was a recent edit that changed the launch year from 1996 to 1995. Can anyone confirm/deny this? --Nikbro (talk) 01:29, 20 June 2008 (UTC)
I still cannot get why MiniDV tape appeared? I can understand the reasoning for large DV tapes, but MiniDV? With Digital8 having exactly the same codec and just slightly bigger cassettes, what was the point in MiniDV? Why Sony created this artificial rivalry between two identical recording standards? So what that MiniDV tape is smaller, it is not VHS to VHS-C difference, the sizes are comparable. Anyone has insights on this? Mikus (talk) 22:14, 18 September 2008 (UTC)
Track widths are mesured in micrometers, 10 and 15 for DV and DVCAM respectively, not millimeters as per a previous edit. This should not be confused with the width of the tape (around 6mm) —Preceding unsigned comment added by 132.185.144.122 (talk) 16:06, 10 March 2009 (UTC)
I went ahead and remove the incorrect reference to Firewire being a feature of the minidv standard. Furthermore, Firewire was being incorrectly referred to as a non-linear editing system. It could be considered a source for non-linear editing.Witczak (talk) 18:32, 24 March 2009 (UTC)
I have reverted the excision of the section on memory chips on DV cassettes. Despite the excising editor's assertion that it was stupid, they certainly did have such embedded chips. Whether or not such chips were EEPROM or not, however, is beyond my expertise. Could someone who knows better please look at that section and correct whatever errors there might be in that description? Thanks. Roregan (talk) 01:27, 11 September 2009 (UTC)
I altered the lead in sentence, as before it said the only format to record Progressive natively was DVCPro Progressive, which is no longer true. HDV 1080p got support to record natively back in 2006. —Preceding unsigned comment added by 98.225.216.197 (talk) 19:04, 11 May 2010 (UTC)
I noticed at the end of the page it indicates that 40 minutes of Digital8 video can be recorded on 1 hour 8/hi8 tapes. This doesn't seem accurate, since a 2 hour 8/hi8 tape will hold 1 hour of Digital8 video. Any thoughts? Brock1912 (talk) 07:08, 10 April 2011 (UTC)
The citation that there is no problem comes from the very tape manufacturer that is causing the problem. Although this could be branded original research, anyone can reproduce the problem more or less consistently (so I don't believe that Sony couldn't). If you have a DV (or HDV) camcorder that has regularly digested only Sony tapes, you will not have had a problem. You can insert a tape from any other manufacturer (TDK actually seems to work best for this purpose) and you will still have no problem. Try several other brands and there is still no problem. But as soon as you put a Sony tape back in, the residue of lubricant left behind on the heads instantly reacts with Sony's (different to anyone elses's) lubricant to form a hard residue on the heads that is difficult to remove. One way of removing it is to ignore the instructions for the cleaning tape and run it through the tape drive for around a minute. A beter way is to use a proper video head cleaning stick and isopropyl alcohol, but I have yet to come across a camcorder design where this last method can be satisfactorily executed. 86.181.54.64 (talk) 13:02, 24 June 2011 (UTC)
The following paragraphs were embedded in hidden comments; I've moved them here instead.
DV has been designed as an interlaced video recording standard. After DV became a preferred format for low-budget digital cinema, it became apparent that filmout process required blending of fields, which caused loss of resolution and exhibited interlace artifacts not noticeable on a traditional interlaced television set. Similar issues arose when Web videos became popular, caused by inability of popular software to properly handle interlaced video. The above issues, along with desire of achieving film look, gave rise to camcorders capable of progressive-scan acquisition.
Recording time can be calculated if tape length is known. For example, standard MiniDV cassettes are loaded with 70 meters of tape. Baseline DV is recorded with 3/4-inch/sec speed, which gives about 60 minutes of recording time in DV mode or 40 minutes in DVCAM mode. Medium size cassettes are offered with tape ranging from 27 to 137 meters in length. Large cassettes can have from 70 to 259 meters of tape, offering up to 126 minutes of recording in DVCPRO25 mode.[1]
CREATE A PROPER COMPARISON TABLE FOR THESE NUMBERS
S: A 65 × 48 × 12 mm cassette can hold 60 minutes of standard DV video.
L: With dimensions of about 120 × 90 × 12 mm the large cassette can hold up to 4.6 hours of standard DV video. 80 minute tapes that use thinner tape are also available and can record 120 minutes of video in EP/LP mode.
Software is currently available for ordinary home computers which allows users to record any sort of computer data on MiniDV cassettes using common DV decks or camcorders.[citation needed] Though originally intended for the consumer market as a high-quality replacement for VHS, L-size DV cassettes are largely nonexistent in the consumer market, and are generally used only in professional settings. Even in professional markets, most DV camcorders support only MiniDV, though many professional DV VTRs support both sizes of tape.((Citation needed|date=August 2008|I've never seen minidv anywhere other than distress purchases (a mortar has just blown up your normal camera), consumer, or "prosumer" hobbyists|[[Special:Contributions/132.185.144.120|132.185.144.120]] ([[User talk:132.185.144.120|talk]]) 16:22, 7 August 2008 (UTC) ))
DVCPRO cassettes are always labeled with a pair of run times, the smaller of the two being the capacity for DVCPRO50. A "M" tape can hold up to 66/33 minutes of video. The color of the lid indicates the format: DVCPRO tapes have a yellow lid, longer "L" tapes made specially for DVCPRO50 have a blue lid and DVCPRO HD tapes have a red lid. The formulation of the tape is the same, and the tapes are interchangeable between formats. The running time of each tape is 1x for DVCPRO, ½x for DVCPRO 50, ½x for DVCPRO HD EX, and ¼x for DVCPRO HD, since the tape speed changes between formats. Thus a tape made 126 minutes for DVCPRO will last approximately 32 minutes in DVCPRO HD.
--28bytes (talk) 23:14, 30 April 2012 (UTC)
References
The article does not explain/tell how data in encoded and/or compressed (like saying its raw PCM for audio cds); so is there such a specification ?--41.41.15.225 (talk) 15:13, 25 March 2014 (UTC)
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Currently the information is:
In both systems the active area contains 720 pixels per scanline, with 704 pixels used for content and 16 pixels on the sides left for digital blanking.
And this is a wrong information. First of all, the whole 720 samples contain image, therefore there is no digital blanking, the image in the first 9 and last 9 pixels are overscan and are not visible, when displayed on CRT, second, 704 is the value for NTSC, for PAL it is 702 samples of active image, 52μ sampled at 13,5MHz is 702 samples. Therefore the correct pixel aspect ratio for PAL is 1,094. 77.113.93.250 (talk) 21:34, 26 October 2019 (UTC)
The result of the move request was: Moved to DV (video format). (closed by non-admin page mover) Reading Beans (talk) 18:22, 10 December 2023 (UTC)
DV → DV (video) – (open to other suggested modifiers, like (format) or (video format)) No primary topic for this digram. Attempting to measure long-term signifiance, searches on Google Books, Scholar, and Search all have very mixed results, including for this video format, distance vector, dating or domestic violence, Diversity Visa, etc. Hameltion (talk | contribs) 20:38, 1 December 2023 (UTC)
The maximum length for DVCPRO HD L-cassettes has made some confusion for me. While maximum length for DVCPRO L-cassettes is 126 minutes in DVCPRO25, these can record 31.5 minutes of DVCPRO HD video. Otherwise, 32-minute DVCPRO HD L-cassettes could record 128 minutes of DVCPRO25 video? It is the true maximum length of DVCPRO large cassettes or numbering error? HarmonZach (talk) 02:30, 10 January 2024 (UTC)