Talk:DV (video format)/Archive 1

Archive 1

1993

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." — Preceding unsigned comment added by 208.59.102.181 (talk) 23:11, 13 November 2004 (UTC)

Color sampling

The Color Sampling section should probably be reworked into just advantages/disadvantages, since it's halfway there already. — Preceding unsigned comment added by 129.33.1.37 (talk) 18:05, 1 December 2004 (UTC)

MiniDV

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 December 2004 (UTC)

What?!

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? — Preceding unsigned comment added by Zilog Jones (talk • contribs) 18:19, 21 March 2005 (UTC)

DVCPro timecode

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. — Preceding unsigned comment added by 85.76.33.58 (talk) 22:09, 13 October 2005 (UTC)

Terminology

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 December 2004 (UTC)

Technically, there ARE definitely cameras that record vastly different formats to the same cassette. Take Digital8/Hi8/Video8 as an example.

The term "dv" in common language is probably used to mean both things (both the codec on the one hand, and the whole format including tape speed, the physical cassette etc on the other). The data stream that is recorded to tape in the Digital8 format is also dv in the correct sense of the word (that is, referring to the codec or data stream). Digital8 is dv. Thus, if referring to a minDV cassette, the correct term to use would be just that (minDV). But I don't think consumers are often aware of this distinction. Thus, I think the term "dv" can refer to a whole lot of things, for example minDV. dsandlund 08:52, 12 February 2006 (UTC)

Type-1 vs Type-2

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 October 2004 (UTC)

If anyone is able to add this information, I would like the article to tell how to diagnose whether a file is Type 1 or Type 2. Robert K S 14:48, 1 February 2007 (UTC)

History and development of the DV format

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) 19:21, 27 February 2006 (UTC)

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. — Preceding unsigned comment added by 213.17.0.36 (talk) 19:38, 7 March 2007 (UTC)

Gamma correction

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. — Preceding unsigned comment added by Wmck (talk • contribs) 10:57, 30 May 2007 (UTC)

DV (miniDV) resolution again

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. -seinman 07:43, 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) — Preceding unsigned comment added by 194.171.252.100 (talk) 12:26, 15 March 2007 (UTC)

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. — Preceding unsigned comment added by Wmck (talk • contribs) 09:23, 1 June 2007 (UTC)

DVC HD

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.— Preceding unsigned comment added by Wmck (talk • contribs) 09:32, 1 June 2007 (UTC)

Compression

"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.— Preceding unsigned comment added by Wmck (talk • contribs) 09:37, 1 June 2007 (UTC)

Photographic documentation

The photo leading this article is not good. Can't someone offer a clearer shot, without a kitschy tablecloth? — Preceding unsigned comment added by Jajafe (talk • contribs) 09:31, 8 June 2007 (UTC)

Readers?

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)

Yes, at school we use a device that my teacher referred to as a "DV Camdeck", which looks like a smaller VCR; connects to the computer via firewire and accepts MiniDV, DV, and rear composite inputs. I'll try to get a more specific model number. Ahanix1989 14:33, 15 September 2006 (UTC)

There is a wide selection of professional and semi-professional DVCam decks, by a variety of manufacturers.. Sony is one of the most common.

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)

DV for data backup

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/. — Preceding unsigned comment added by 134.181.64.225 (talk) 04:34, 20 February 2004 (UTC)

Only one I know of is dvbackup, which is Free Software. I've never used it myself. --Brion 05:41, 20 Feb 2004 (UTC)

There's also another one for Windows, DV Streamer. Unfortunately, DV Backup is Mac OS X only, and dvbackup is Linux/Unix/POSIX OS only. Backing up data to DV reminds me of the old systems back in the 80's that allowed you to back up your computer's data to a analog VHS videocassette by installing a special ISA-bus card that interfaced to your VHS/Betamax/what-have-you VCR. Videotrax and Corvus were companies that made such hardware for backing up to VHS. misternuvistor 03:22, 2 February 2006 (UTC)

Yes. In fact, I feel the article is incomplete without it. Searching for this info is what lead me to this article. -- Bilbo1507 (talk) 15:52, 14 March 2008 (UTC)

miniDV - DVC Pro compatibility

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 — Preceding unsigned comment added by 132.185.240.122 (talk) 10:11, 4 September 2006 (UTC)

DVCPRO cassettes are smaller than big-shell DVCAM. I'll try and take a photo to replace that grotty one on the front page. — Preceding unsigned comment added by 91.84.80.40 (talk) 15:21, 2 February 2009 (UTC)

Isn't DCT intraframe compression the same as MJPEG?

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? — Preceding unsigned comment added by 212.61.57.82 (talk) 07:46, 21 May 2007 (UTC)

The differences are in the subtle details of implementation, particularly the number of quantisation tables available for each frame. This effectively means that DV has more flexibility in choosing how to compress various bits of the picture than JPEG does, which results in higher average SNR. Deeper information than that would probably be outside the scope of the article.

I believe DV has one quantisation table per macroblock, but don't quote me. — Preceding unsigned comment added by 91.84.80.40 (talk) 15:21, 2 February 2009 (UTC)

Launch year

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)

Can't confirm or deny absolutely, but 95 was the year I had in my head. — Preceding unsigned comment added by 91.84.80.40 (talk) 15:21, 2 February 2009 (UTC)

MiniDV vs Digital8

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)

Digital 8 was released in 99, and post-dates DV. I can only speculate on Sony's intentions for D8, but the cameras could mainly play back Hi8 tapes and it would therefore have made a sensible upgrade for a Hi8 user. It was also mooted at one point that Sony had a lot of Hi8 deck mechanisms to get rid of, but that sounds apocryphal to me. The real problem with D8 is that most of the cameras released in the format just weren't that good. — Preceding unsigned comment added by 91.84.80.40 (talk) 15:21, 2 February 2009 (UTC)

Track widths

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)

Indeed, it looks like you are correct. Sorry for the bad edit. But thanks for the correction. Cheers —fudoreaper (talk) 06:42, 11 March 2009 (UTC)

Firewire is not a "feature" of minidv

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)

Memory chips and EEPROM

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)

Locked audio

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)

DCT blocks

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)

I would like to see the 2-4-8-DCT mentioned in the article and to be explained based on the usual (as most readers know from jpeg) 8-8-DCT (one sentence: "Since video is sometimes interlaced, there are two natural possibilities to apply the DCT: 2-4-8 for action scenes and 8-8 for a mostly still backgrounds with some small moving figures"). -- Arnero (talk) 09:12, 22 March 2010 (UTC)

DCT macroblocks

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)

DCT superblocks

According to Jack (op cit.) each superblock consists of 27 macroblocks. So:

• 480i 4:1:1 = 50 superblocks in 5 columns x 10 rows per frame,
• 480i 4:2:2 = 100 superblocks in 5 columns x 20 rows,
• 576i 4:2:0 = 60 superblocks in 5 columns x 12 rows,
• 576i 4:2:2 = 120 superblocks in 5 columns x 24 rows.

Redbobblehat (talk) 15:39, 3 September 2008 (UTC)

• Does this mean that superblock- and macroblock-level DCT artefacts for 4:2:0 will be square but horizontal rectangles for 4:2:2 and 4:1:1? Redbobblehat (talk) 15:39, 3 September 2008 (UTC)

Yes. The received knowledge that "you can't key DV" mainly refers to NTSC DV and all varieties of DVCPRO, where the long, thin, 4x1 pixel chroma rectangles are very visible, and a real bind. PAL DV, with similar horizontal chroma resolution to a 4:2:2 format and identical vertical chroma resolution, keys far better (I've done a lot of it). — Preceding unsigned comment added by 91.84.80.40 (talk) 15:21, 2 February 2009 (UTC)

Progressive recording

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 changed it back, because HDV is not DV. If you interested about HDV, you can just follow the wikilink and read all about it, including native 1080p option. Mikus (talk) 22:59, 13 May 2010 (UTC)

Video resolution

what's the video resolution of ordinary mini dv recordings? how does it compare to DVD? RustyCale 13:27, 22 May 2005 (UTC)

I'm not a video expert, but I would assume that all else equal, mini dv tape would be higher resolution than dvd. Of course a lot depends on what kind of camera is used, and many of the cheaper mini-dv camcorders don't have the best micro-processors, zoom lenses, image processing chips, etc. But with the same camera, it would make sense that the mini dv tape would be higher resolution because one hour in the standard sp mode is about 13 GB, whereas two hours of standard bit-rate dvd is about 4.5 GB. So the DVD has a lot fewer GBs per hour, indicating that it's probably a somewhat lossy compression. That should change with the next generation of dvds - blue ray and/or HD-DVD. Of course with a traditional CRT tv you can't see any of that difference (except maybe with the dvd player's zoom function), since the tv itself is too low resolution. Blackcats 07:49, 30 May 2005 (UTC)

I would like to clarify two things here: First, dv is a lossy format, just like dvd/mpeg2. Compression artifacts are very visible at magnification. Second, the two formats (dv and mpeg2) store video in completely different ways, making comparisons by bitrate rather irrelevant I'm afraid. The answer is that It depends.

One point that really should be brought into the article however is the actual pixel resolution of the dv format. This rather central piece of information has been completely overlooked. dsandlund 08:40, 12 February 2006 (UTC)

But keep in mind that the contrast is not compressed, only the color space. So DV is only a lossy format for the color informaiton in the compressed video. LexieM 19:17, 27 February 2006 (UTC)

No. Both are compressed, using the same method (which is almost identical with JPEG-compression). What you probably have meant, was, that before aplying that compression (DCT, quantizing etc.) the colour informations are subsampled (making the arrays of Cb- as well as Cr-numbers, which represent the picture, smaller), while the luminance/grey array is preserved (at 720x480 or 720x576 values). So, luma and chroma don't differ in compression, but in subsampling. Btw, 720x480x30 (and 720x576x25 too) makes 10.368.000 values(usually bytes) per second, which is ~3x the datarate of DV. ShapedNoise 22:26, 25 February 2007 (UTC)

Although the luma information is not subsampled in the digital domain, it is nevertheless passed through a low pass filter in the analogue domain (i.e. prior to digitisation). This is deliberately designed to remove excesive detail from the luminance image so as not to over stretch the compression algorithm. This is intended by the format to be a physical low pass filter in the analogue signal path, but many camcorders from the lower end of the market omit the filter and rely on the poor quality of their chosen lens to do the same job in the optical domain (rarely as effectively). 86.178.9.171 (talk) 19:46, 2 November 2010 (UTC)

When talking about recording a full frame (not widescreen) video with an aspect ratio of 4:3, Mini DV typically records with a resolution of 720x480 rectangle pixels. DVD uses square pixels, which squeezes the resolution to 640x480, creating a true 4x3 aspect ratio. 720x480 has an aspect ratio of 3:2 because of the rectangle pixels. El Mariachi94 05:50, 1 December 2006 (UTC)

I think you've confused a few different things? Both DV and DVD use rectangular/non-square pixels. In NTSC DV, not all the pixels are used for active picture area, so this is why the 720X480 pixels don't make a 4:3 picture (although the active picture area does). [1] Something like that. Glennchan 03:28, 2 December 2006 (UTC)

Reading the link you've posted thoroughly, made my head ache :(

But, i'd like to say this: the number 720 is common for both NTSC and PAL. I've read, that the CCIR601 standard defines the sampling frequency (for digitizing of those analog formats) to be 13.50 MHz, and to be equal for them both. The length of PAL row is 64.0 us and the active/visual part lasts 52.0 us, NTSC's row lasts 63.5 us and its active part ...('ve forgot,sorry). These intervals are almost equal on both sides of The Ocean.

So, to simplify the everyday bread of tv-companies (NTSC <-> PAL transcoding), they've decided to apply the same f_samp for both. Thus the horizontal resampling would be no longer needed; though the difference in number of rows (height of picture, measured in pixels) as well as in framerate, still stays alive.

Another limit, which applied to their deciding: Both width and height of the digitized pic must be a multiple of 16, because the compression involves slicing into 8x8 tiles, and because the Cb and Cr parts are twice-subsampled (2x8=16) (an eventual use of 4:1:1-subsamp probably implies even 32 instead of only 16).

So, checking the numbers against 16: 720-ok, 360(=720/2)-fails; 704-ok, 352(=704/2)-ok; 576-ok, 480-ok.

Another computations: 720px / 13.50Mhz = 53.33 us, which is a bit more than that 52.0 us. So, creating 601'compatible material by digitizing analog PAL (NTSC probably too) (e.g. a playing VHS or a demodulated live TV signal) will introduce some black pixels/columns on the left and right side. On the other hand, if it's created by native digitally-acquiring devices (like DV, DigiBeta,..), then even the sidemost pixels contain valid visual info and there's no need/reason to crop them. Please look at the grab-monitoring or replay window to check if i'm not fooling.

DV and DVD (and probably most other Stand.Def. formats too) use the same 'grid' of pixels. In US&JP, it implies a pixel to be slightly-portraitic, and in Eur slightly-landscapic (cause they both have the same number of 'columns', but differ in number of rows). Thus, doing some resampling when converting from DV to DVD (not to confuse this with transcoding), is, imho, not a good idea.

Some people don't like nonsquared pixels stretched or shrinked on their monitors. Hmm. I also didn't. But. Doing the resampling, with a factor very near one (e.g. 0.92, 1.07, or so) is a very risky operation, especialy if the content is very sharp (i.e. the content goes almost to the Shannon's limit). Then, such resampling may end with very ugly results. Maybe that using some more clever algorithm (e.g. bicubic instead of linear) heels this a bit, but still is far from ideal. Paradoxially, resamp. with more-far-from-1 coeff. (like 0.73 or 1.39) will probably usually end with much nicer results.

So, i'd rather stand the non-ideal proportions than having to stare at the resampling artifacts. Additionally, many monitors (CRTs, and LCDs too) don't have the same ratio of native resolution and physical screen dimensions (e.g. view 1280x1024 (=5:4) on 16"x12" (=4:3) screen. So sometimes/often the nonsquareness may survive even after resampling :(

Finally, i've got a very constructive suggestion: we should throw some putrefying tomatoes at those standard-creators and device manufaturers, as an expression of our big thanks for that pixel ratio chaos they've created for us :)

Enough for today, tired, going to cool-down my brain :) See you laters. Give some response in between. ShapedNoise 01:45, 26 February 2007 (UTC)

Somewhat late, but to answer the original question: In theory, MiniDV should have a better picture quality than DVD. This is because the video is compressed spatially on a frame by frame basis. There is no temporal compression for MiniDV. DVD on the other hand, is both spatially and temporally compressed. This advantage of MiniDV is somewhat negated by the necessity of having a low pass filter in the analogue domain to prevent the digital data stream exceeding the capabilities of the fixed data rate written to the tape. The newer HDV format, by contrast, is both spatially and temporally compressed. 86.183.24.235 (talk) 17:38, 6 March 2011 (UTC)

Tape lifetime

Does anyone know if/when the tapes fatigue? GChriss 22:35, 18 March 2006 (UTC)

To add to this question, a section on proper head cleaning would be helpful as well. Thanks, GChriss <always listening><c> 19:15, 21 September 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)

At a certain point, there would be too much tape shedding of the tape surface. This was a problem with LINEAR editing I believe, from shuttling the tape around. ME is not quite as robust as MP tape. I don't have actual figures myself though. Glennchan 22:28, 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

From my personal experience: I've not experienced any deterioration in tapes I've recorded over 8 years ago (even though I didn't actually bother with the "winding back and forth periodically" advice). Having said this: I use tapes once only, ie. I do not re-record. However, I did not look for a formal article about this, but if we really get stuck, I'll write one :) George Adam Horváth (talk) 09:56, 7 March 2011 (UTC)

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)

Mixing tapes from different manufacturers

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)

Hidden text

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.

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. 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

Digital8 recording times

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)

PAL tapes in D8 mode can record 2/3 of tape capacity in Hi8 mode, but in NTSC it is only 1/2. 77.113.93.250 (talk) 21:28, 26 October 2019 (UTC)

Encoding / compression

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)

ITU REC.601 wrong information

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)