Paste as plain text instead. Only 75 emoji are allowed. Display as a link instead. Clear editor. Upload or insert images from URL. Share More sharing options Followers 0. Reply to this topic Start new topic. Recommended Posts. Posted February 28, I agree. I think for convenience we should shot on Mini-DV. Link to comment Share on other sites More sharing options It appears to be the 8mm division's way of keeping its customer base from defecting to DV. By leveraging the massive investments of 15 years in 8mm analog camcorders and transports, the unit cost of Digital8 gear is kept very low, roughly half of what a comparable DV camcorder would cost, and its ability to play back legacy analog tapes is worthwhile for those with large libraries of 8mm.
Hitachi also produced Digital8 camcorders although these seem to be hard to come by thanks to James M. DeLuca for bringing these "stealth" camcorders to my attention.
All Digital8 camcorders can record from the analog inputs at least outside the EU , and all are equipped with i. Link ports for digital dubbing and NLE connections. On a scale of 1 to 10, where 1 is just barely video and 10 is as good as it gets, I would arrogantly rate assorted formats as follows:.
My feeling was that while D-2 and D-3 are excellent first-generation formats for composite analog playback and NTSC broadcast, the compositing of color with luma which includes a color bandwidth limitation even more severe than DV or BetaSP employ makes clean multigeneration and multi-layer image compositing problematic at best even such simple things as adding titles.
However, I was severely upbraided by several folks with extensive digital composite experience, who all rated D-2 and D-3 between DV and DigiBeta. If you've got a high-end all-digital postproduction chain, the quality in these formats holds up over multiple generations extremely well, much better than any analog format, be it component or composite. While this is certainly true, if you don't have that all-digital pathway, I'm doubtful about how they would fare Again, folks who live in high-end digital suites all day suggested this, and I have to agree.
But after you sit in front of analog component or digital monitoring using BVM or Panasonic broadcast-grade monitors, your attitudes start to adjust upwards, and you start to discern differences between the merely very good stuff and the truly excellent stuff a bit more readily! Please note that I'm rating the formats here, not any particular implementation.
Don't confuse the images produced by a bit of equipment with the underlying capability of its recording medium.
Sony rates BetaSP's luma frequency response to 4. Oxide playback i. Chroma resolution on BetaSP is essentially the same as on DV, so were BetaSP a digital format, its sampling might be characterized as for comparison purposes. Of course, BetaSP is not sampled on a fixed spatial grid, so such numerical comparisions should always be taken with a grain of salt.
I am hoping to get permission to repost that article on my site, as it's no longer available on DV's website nor in the Internet Archive. The most noticeable spatial artifact is mosquito noise around any sharp, contrasty edges.
These are compression-induced errors usually seen around sharp-edged fine text, dense clusters of leaves, and the like; they show up as pixel noise within 8 pixels of the fine detail or edge causing them.
The best place to look for them is in fine text superimposed on a non-black background. White on blue seems to show it off best. The magnitude of these errors and their location tends to be such that if you monitor the tape using a composite video connection, the artifacts will often be masked by dot-crawl and other composite artifacts. A spatial quilting artifact can sometimes appear at the boundaries between 8x8 pixel blocks, most noticeable on shallow diagonals or on slightly-defocused backgrounds, typically when there is some motion in the scene to make the fixed "grid pattern" a bit more obvious.
Some DV codecs seem to be much more prone to this than others, and with a few the quilting really starts to appear only after a few generations of rendering. Motion blocking occurs when the two fields in a frame or portions of the two fields are too different for the DVC codec to compress them together.
Motion blocking is best observed in a lockdown shot of a static scene through which objects are moving: in the immediate vicinity of the moving object say, a car driving through the scene , some loss of detail may be seen. This loss of detail travels with the object, always bounded by DCT block boundaries. However, motion blur in the scene usually masks most of this artifact, making this sort of blocking almost impossible to see in most circumstances.
Finally, banding or striping of the image occurs when one head of the two on the scanner is clogged or otherwise unable to recover data. The image will show 10 horizontal bands 12 in PAL countries , with every other band showing a "live" picture and the alternate bands showing a freeze frame of a previous image or of no image at all or, at least in the case of the JVC GR-DV1u, a black-and-white checkerboard, which the frame buffers appear to be initialized with.
Most often this is due to a head clog, and cleaning the heads using a standard manufacturer's head cleaning tape is all that's required. It can also be caused by tape damage, or by a defective tape.
If head cleaning and changing the tape used don't solve it, you may have a dead head or head preamp; service will be required. This sort of banding dropout occurs fairly often; about once per DV tape in my experience. Usually it isn't even noticeable -- a single frame of banding due to a momentarily clogged head won't be visible unless there's motion in the scene to show off the frozen stripes. Have a look through your old tapes frame by frame on a slow day, of course!
DVCAM, with its 15 micron track width, or DVCPRO with its 18 micron track, are sufficiently on the safe side of the bleeding edge so that this sort of droput is much less likely to occur.
One visible dropout per hour-long tape, on average, is not something to get flustered about. The tape data rate is doubled to 50 Mbps video and the compression work is split between the two codecs. The result is a image compressed about 3. It's visually lossless and utterly gorgeous. Think of Digital Betacam, albeit at 8 bits instead of 10, at a bargain price. Only JVC is supporting this format, which has resulted in a less-than-headlong rush by the video community to embrace it.
Watch it, though; it's hot. If you're doing high-end EFP on a budget, this is the format to use. DVCPRO50 kit is also a lot more portable and lightweight than D-9, so it's the format of choice if you're doing high-end EFP with a somewhat bigger budget and you want to keep your camera operators from wearing out as quickly!
Both firms gang four DV codecs together to get the Mbps datastream, while preserving the same equipment form factor and operational methodologies used in the current 50 Mbps products.
Thus the line DV formats have slightly lower luma resolution than HDCAM but slightly better chroma resolution see the next section for a discussion of sampling. I have not found a second source for this information, so I can't confirm it. It should be noted that both Panasonic and JVC are well-placed to serve the growing DTV market whatever image format a broadcaster selects.
The first number refers to the The The other two numbers refer to the sampling rates of the color difference signals R-Y and B-Y or, more properly in the digital domain, Cr and Cb. Thus you have color samples in each of Cr and Cb per scanline.
The Cr and Cb samples are considered to be co-sited with every fourth luma sample. Yes, this sounds horrible -- but it's still enough for a color bandwidth extending to around 1. Fortunately not! Chroma is sampled times per line, but only on every other line of each field.
The theory here is that by evenly subsampling chroma in both H and V dimensions, you get a better image than the seemingly unbalanced , where the vertical color resolution appears to be four times the horizontal color resolution.
Alas, it ain't so: while works well with PAL and SECAM color encoding and broadcasting, interlace already diminishes vertical resolution, and the heavy filtering needed to properly process images causes noticeable losses; as a result, multigeneration work in is much more subject to visible degradation than multigeneration work in But wait, there's more!
Practically speaking, this is a headache for developers of codecs, encoders, and DVEs, but for DV purposes it's not especially exciting, since only European DV is Sometimes there is a reason for the higher prices that the poor Europeans are saddled with when it comes time to purchase gear Part of the standard JVC sales pitch for D-9 is the superiority of which is true , and the utter doom and degradation that awaits you should you try to do anything -- including chroma-key -- with a format which is, shall we say, a wee bit exaggerated.
But that doesn't mean that you can't do very satisfactory work in Just be sure you take the hype with a grain of salt. True, the chroma performance of formats is superior to formats, especially in multigeneration analog dubbing.
But by the same token, is as superior to as is to or Where DV can get into trouble is that the coarse resolution of the chroma signal only samples per scanline in leads to a very regular, "steppy" key signal, most noticeable on near-vertical edges or vertical edges where motion is present, especially if the codec's decompression simply replicates the chroma sample across the intervening pixels instead of low-pass filtering or interpolating between samples.
The Matrox RTX. Using these tools I can make very clean and acceptable keys, certainly for hard-edged keying. You may also find that layering different key signals gives you excellent results. I've used a heavily-choked chroma key to cut my main matte, but then add one or two luma, extract, or difference keys to define the edge detail that the chroma key can't get.
Each luma key may only work for a small part of the image; it may lose the greenscreen background but also lose the interior of a similarly-bright face. However, it usually is able to get edge detail, because the edges of a person fall off in shadow or are picked out brightly by the rimlight, and the chroma key holds the interior matte that the luma key won't provide. I simply kick myself for not trying it out sooner! John Jackman has some good examples of DV keying on his post-production pages at greatdv.
Of more concern is that DV artifacts, especially mosquito noise, may become annoyingly prominent when upconverted. However, the jury is still out on this; I've performed upconversions without excessive artifacts, but a lot depends on the subject material. Again, reducing edge enhancement helps. Also, HD material is The way many DV cameras produce by throwing away vertical resolution is enough to send shudders up my spine for SDTV work; for HD, it'll be a complete disaster.
Perhaps I should add a section on shooting for HD upconversion; there are lots of issues No decompression or recompression occurs. If a digitally-perfect copy is a 10, and a point-the-camera-at-the-screen-and-pray transfer is a 1, here's how DV picture quality holds up over different transfer methods:. Since a transfer is a direct data dump, this is understandable; if a cross-format transfer were to be possible it would require that one deck or the other "translate" the signal to or from the DVCPRO data format to the Blue Book format.
Remember, DVCPRO was designed first and foremost as an ENG format; robustness of the signal was paramount, and interconnection of gear in the ENG world is done via analog or via SDI is too limited an interface for the broadcast world, where the ability to switch and route video over thousand-meter runs is both necessary and taken for granted; has a length limit of 4.
This economy measure is simply one of allowing the audio clock to "hunt" a bit around the desired frequency; the phase-locked loop or other slaving method used to keep the audio sampling in sync with the video sampling can have a bit more slop in its lock-up, with the audio sampling sometimes running a bit slower, sometimes a bit faster, but always staying in sync over the long run.
It's the difference between walking a dog on a short leather leash, always forcing the dog to stay right by your side locked audio , and using a long, elastic leash or one of those "retractable clothesline" leashes that allows the dog to run ahead a bit or lag behind unlocked audio. In either case both you and the dog will get where you're going at the same time, but along the way the "unlocked" dog has a bit more freedom to deviate from your exact walking pace.
Unlocked audio should not cause audio sync to drift away from video over a long period of time. I have shot one-hour continuous takes of talking heads with a consumer DV camcorder DCR-VX and experienced no drift at all between audio and video.
Final Cut Pro through version 1. Also, many non-linear editors output 16 bit Many thanks to Earl Jamgochian at Sony for filling in and clarifying many of the details in this section. Sonys, by contrast, seem to average Clocking rates for other cameras were not discussed. In normal playback of the DV tape this isn't seen, since on playback the audio is played back based on its embedded clocking data, in sync with the image. Both the audio and video slave to the data samples in each packet; as these are commingled in the DV datastream, the sound and picture will always play back in sync.
It's worth saying again: when playing a DV tape, audio never drifts, regardless of whether it's locked or unlocked. Final Cut Pro allows captures limited only by available disk space, and the QuickTime media format used treats audio and video as separate tracks, each with its own time reference. If you are shooting weddings or corporate videos you may also find clients start to ask for their video in widescreen too - because more and more people have widescreen TVs at home and at work.
If you already have a camera and can't afford to upgrade to , then there are three ways to get it To be honest, if you are going to go through all of that palaver, you would be better off selling your camera and putting the money towards a native camera.
All the new HDV cameras are also These usually don't zoom out wide enough, so make sure you have money in your budget for a wide angle adapter. With lenses you get what you pay for. Spend as much as possible to get the best quality. It can be difficult to cover all eventualities with just one lens so most professionals have at least two zoom lenses - one biased towards telephoto and another that goes very wide.
Do check how your lens behaves at the extremities. As you zoom out, you may notice that strong verticals become curved barrelling and that the corners of the picture get darker vignetting. Lens ramping occurs when you zoom in, if you are in manual you will see the f number change and the result is that the picture will get slightly darker - a problem if you want to do a lot of night shooting.
A good lens minimises all these characteristics. The PD and PD are well know for their good low light capabilities - compared to cameras of a similar price. If you get a chance to check out cameras at a trade show, notice how bright the stage sets are.
Then note the f number on the lens. Most will be around f8 or f11 i. Pictures always look great with a well lit subject. If possible, pan the camera round to a dark area of the hall adjust the iris accordingly and check picture quality in low light.
Does it still look good? How sensitive is the camera? Did you need to add some gain? If so, how much? The best give you control over the brightness and contrast. Most flip-out LCD screens are difficult to see in bright sunlight. So, you may want to buy a cover to shade it and improve picture quality. The Hoodman is simple but effective - check it out at www.
Petrol also does a sun shade , click on the accessories tab on its website. You also need to angle the LCD for a decent picture. However, angling the screen can make the picture seem brighter or darker, which is not very useful if you are relying on it to help you get the exposure correct - for that you should also use Zebra stripes. Of course, one of the best things about a colour screen is the ability to check if the white balance is correct.
On cheap low-end cameras, audio input is via a mini jack. These sockets will eventually become loose and the sound one-legged or intermittent. Professional mics tend to come with XLR connectors which are robust enough for daily use and abuse. So, if you can afford it buy a camera with XLR sockets and plugs. If your choice of camera has a mini jack for audio input eg VX, VX - you will need an adaptor to plug in professional microphones. Beach Tek makes an add on sound box that enables you to convert a minijack into two XLR sockets.
Do make sure you get the one with phantom power if you own a gun mic. There are several ways to take pictures out of the camera, besides ejecting the tape. This allows you to play straight from the camera into an editing system - handy if you use a laptop to edit on location. High-end cameras have BNC outputs and inputs that enable you to link two cameras together to lock timecode.
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