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MillimeterHDV@Work
Sep 26, 1997 12:10 PM
What is Optimal Exposure? Part 4 of 4
In Parts 1 through 3 we examined how to obtain optimally exposed images. But there is one more production consideration.
With an HDV camcorder, such as the JVC GY-HD100 that has a professional lens, you can easily control exposure via the aperture. Of course, that assumes you have a calibrated field monitor. Minimally, for exposure calibration you’ll need a source of SMPTE color bars (with a pluge bar) that the camcorder provides, a blue filter or "display blue only" mode, knowledge of the calibration process, plus display adjustments for contrast (white level) and brightness (black level). While the HD100 offers a LCD contrast control, only the viewfinder has both contrast and brightness adjustments. Therefore, once calibrated, only the viewfinder should be used for exposure control.
If, however, your camcorder’s displays do not have both Contrast and Brightness adjustments—as is the case with other HDV camcorders—you will need a separate field monitor that can be calibrated.
Now we’ll look at how to preserve this image while editing.
As you know, the range between black and white is the grayscale. The more levels (i.e., resolution) in the grayscale, the better image quality will be. Most video equipment records using 8-bit digital samples that provide—per color—256 levels (values of 0 to 255). The number of definable color values possible with 8-bit systems is approximately 16 million—the same number as with a 24-bit computer graphics card.
IRE is an old name for IEEE units, but it is still used. Legal video signals range between –40 IRE (sync-tip) and +110 IRE. With an 8-bit system, white (100 IRE) is represented by a value of “200.” Camcorders allow brightness to exceed the nominal intensity of white. The following digital values are available for the “super-white” range of 100 to 110 IRE: 201 to 235. During calculations, values can exceed 235, but are never allowed to become 255.
So does that mean black is zero? No. Black has a digital value of "16," which allows for a range “super black” values (from “15” to “0”). However, when digital values are converted to analog signal levels, the situation is more complex. In the Japanese NTSC, PAL, and HD, a digital value of 16 is converted to 0 IRE. With the U.S. NTSC system, after 16 is converted to an analog signal, the output voltage is increased slightly. Using the IRE scale, black becomes +7.5 IRE. The voltage increment, called “pedestal” or “setup,” is a legacy of the way the U.S. television system was designed. It is not a good legacy, as it slightly reduces the range of the USA NTSC grayscale. (Note, setup should not be added during recording, as some camcorders allow. If used at all, setup should be used during playback to match NTSC calibrated monitors.)
There is another problem with the U.S. system. Consumer and prosumer NTSC equipment imported from Japan into the USA, as well as all HD equipment, do not have setup. Thus black is 0 IRE. That means a monitor correctly adjusted for a 7.5 IRE pedestal will not be correct for non-pedestal sources. Conversely, if the monitor is correctly set for a 7.5 IRE setup, dark gray shadows from a 0 IRE source will disappear into black. Alternately, if the monitor is adjusted for a 0 IRE source, an NTSC source will have dark gray rather than black shadows.
As we have learned, digital YUV/YPbPr video signals range from "16" to "235." Computer software works with RGB data that is also 8-bit. Each red, green, and blue value ranges from 0 to 255. Therefore, it would seem video and computer digital should be compatible.
Unfortunately, they are not. Digital YUV video must undergo processing to be converted to/from RGB. This process can degrade chroma quality. Moreover, the YUV and RGB color spaces are not identical. There is, however, another problem.
The digital YUV value of black (16) is mapped to an RGB value of zero. And the value of white (200) is mapped to an RGB value of 255. What happens to all the recorded superwhite information between 101 IRE and 110 IRE? It is hard-clipped and thereby lost. Thus, all information from the digital YUV range from 201 to 235 is discarded by NLEs that utilize RGB rather than YUV processing. Thus you should choose an NLE that works with YUV signals that can handle superwhite. For example, if you want to edit HDV with Premiere Pro, you should also purchase AspectHD from CineForm because the AspectHD software renders its effects in YUV, rather than RGB space. Moreover, both superwhite and superblack are supported.
Lesson 4: The production and postproduction of HDV-based video involves far more than buying a camcorder of a certain brand or with a specific feature set. Production errors that would be insignificant viewed on an NTSC TV will be major blemishes when displayed on very large screens at high resolution.
Canon introduces new XL H1 HDV camcorder
As Canon's first HD video camera, the XL H1 High Definition (HD) camcorder and 20x HD video zoom lens provide broadcasters with a low-cost 1080i resolution option for ENG, documentary, or reality TV production. Filmmakers will also appreciate the extensive Cine controls and 24fps option the XL H1 camcorder offers. Canon's "professional jackpack" features include uncompressed digital HD-SDI output for seamless integration into broadcast studios or high-quality image transfer to nonlinear editing systems. The Genlock feature allows movie sets to synchronize camera settings easily across multiple camcorders and SMPTE timecodes in and out allow for streamlined tape and edit management.
"As FCC deadlines for transferring all television content to digital rapidly approach, broadcasters are looking for low-cost acquisition options that do not require them to revamp their entire infrastructure," said Yukiaki Hashimoto, senior vice president and general manager of the Consumer Imaging Group at Canon U.S.A., Inc., a subsidiary of Canon Inc. "By offering backward compatibility with current SD-based infrastructure, the XL H1 HD camcorder combines the right features at the right price to meet the demanding needs of television production and movie making."
The XL H1 camcorder has three 1/3in. 16:9 interlaced CCDs that capture images at 1080i resolution. The camcorder features selectable frame rates of 60i, 30-frame, and 24-frame to allow the user to adjust to the assignment at hand and can switch back to SD resolution if needed. At the 30-frame rate, broadcasters can capture high motion, like sports with confidence that each frame is captured individually and completely. Filmmakers can utilize the 24-frame rate when creating the look and feel of movie film. The 60i frame rate, meanwhile, delivers exceptional resolution for shooting environments like ENG or reality TV.
The XL H1 HD camcorder is the first model to include Canon's proprietary DIGIC DV II image processor. DIGIC DV II is an image processor that can process both HD and SD video signals as well as still photos, while maintaining the correct color space for each mode.
The XL H1 camcorder's professional jackpack terminals consist of three key features designed to streamline production: HD-SDI output, genlock, and SMPTE timecode input and output.
To streamline in-studio television production, the XL H1 model offers HD-SDI and SD-SDI output. HD-SDI output allows professionals to directly connect to a TV control room or a nonlinear editing system. With this feature, users can plug their XL H1 camcorder into any professional's system with an HD-SDI input and can deliver live, unfiltered HD content in all its brilliant detail. With other HDV models on the market, the user must feed the HD signal into an analog-to-digital signal converter box which adds an extra step, not to mention an extra cost. The XL H1 camcorder can also record to HDV Master recording media or MiniDV tapes.
Multi-camera shoots with the XL H1 model are no problem thanks to the camcorder's Genlock synchronization input feature. This feature allows many XL H1 camcorders to synchronize through a switcher. With its SMPTE time code input and output, multiple cameras on a shoot can all lay down the same timecode. The XL H1 camcorder uses a customizable open-architecture approach, selectable frame rates, and multiple output options so professionals have exactly the right tool, every time they need it.
Each year, the number of filmmakers turning to video-based acquisition solutions for movie production grows. Moviemakers that shoot video place strong emphasis on delivering the "film" look to their pictures. Canon's new XL H1 camcorder offers filmmakers the ability to customize their video recordings using a number of variables, including three color matrices for a wide range of color correction and two cine gammas for intricate adjustment of dynamic range; there's also customizable knee, black stretch, horizontal detail, coring, sharpness, noise reduction, color gain, hue, and master color adjustments. Each one of these settings can be modified independently, thereby giving the camera operator precise control over the "film-like" appearance of their video.
In addition to its extraordinary video capabilities, Canon's XL H1 HD camcorder can capture still images plus metadata at full HD resolution (1920x1080 or 2.1 megapixels) onto a standard Secure Digital (SD) Memory Card and MMC media. The Photo button on the outside of the camcorder allows users to capture still images at up to five frames per second. Camcorder settings also can be stored on the memory card and transferred to another camcorder so setup can be replicated.
The XL H1 camcorder's still image capture plus metadata feature provides an in-camcorder solution for cinematographers and directors to check for scene continuity and provides added backup to any still photographers on set.
Canon is launching a new multi-functional color electronic viewfinder (EVF) and 2.4in. 16:9 LCD monitor with Safe Area Marking built-in; black and white mode; Zebra Pattern (70-100 IRE); Horizontal and Vertical flip; and a Distance Readout (using 20X HD video lens).
As a menu option, users can chose to view Aspect Ratio Guides in the viewfinder. Canon provides a choice of 4x3, 13x9, 14x9, 1.66:1, 1.75:1 1.85:1, and 2.35:1 guides. The XL H1 HD camcorder viewfinder also includes a feature called Focus Help. The first setting, Peaking, creates an exaggerated line in the viewfinder that disappears when the image is focused. The second setting, Magnifying, enlarges the viewfinder image, helping the camera operator better see if the image is properly focused.
The new XL H1 HD camcorder features Canon's XL interchangeable lens mount. For the XL H1 camcorder, Canon drew upon its exceptional heritage and expertise in designing and manufacturing lenses for photography and broadcast TV to create its new 20X HD video zoom lens with Superior Canon Optics. This lightweight, high-performance lens achieves fast, precise focusing and a unique balance of focal length, angle of view, and depth of field.
In addition it incorporates multiple Fluorite elements for superior contrast, resolution, and color fidelity through the reduction of chromatic aberration. The 20X HD video lens offers a fast f/1.6 to f/3.5 aperture for users that shoot under the most demanding lighting conditions and a close focusing distance from only 20mm away (when at wide angle). At an aspect ratio of 16:9, the 20x zoom range is an impressive 38.9mm to 778mm (35mm equivalent). At the 4:3 aspect ratio, it is an equally impressive 47.4mm to 954mm (35mm equivalent). The lens features a 72mm filter thread, two independent ND filters (1/6, 1/32), focus and zoom presets, and optical image stabilization.
Canon's Super-Range Optical Image Stabilization (OIS) system corrects camera shake instantly, so even handheld shots at full telephoto and shots taken from a moving car are smooth and steady. Because it is optical, it can compensate for a greater degree of camera shake and avoids any loss in image quality, unlike some electronic image stabilizers.
Other optical image stabilizers use a gyro sensor to detect camcorder vibration (the data from which controls a vari-angle prism that continuously corrects the path of the incoming light). Canon's SuperRange OIS system goes one step further by examining the image after the CCD receives it and detecting any low-frequency vibrations missed by the gyro. This data is fed back to accelerate and refine the movement of the vari-angle prism. This greatly improves performance for low-frequency vibration, resulting in the most advanced optical image stabilization available today.
The XL H1 camcorder and the 20X HD video lens will be available as a kit in November for an estimated selling price of $8,999. For more information, visit www.usa.canon.com.
AlphaDogs to demonstrate Avid Xpress Pro's HDV capabilities
AlphaDogs Inc., a postproduction studio in Burbank, Calif., will host a product demonstration of Avid's Xpress Pro, which combines professional video, audio, film, effects, DVD authoring, and encoding tools, with expert tips from Avid senior product marketing manager Tim Wilson at its Editors' Lounge event on Friday, September 30, at 6:30 p.m.
The event will also offer a sneak peek at Avid's Xpress Pro with HDV functionality, which is scheduled for release to PC editors in a few weeks. Editors and post professionals will have an opportunity to learn how Xpress Pro with HDV functionality allows editors to mix different formats - HDV with DVCPRO HD and SD - all in realtime. In addition, Editors' Lounge attendees will get a preview of how different formats and equipment can work together (Sony, JVC, Canon, 720, 1080, 24P, etc.) on the new system.
The Editors' Lounge will begin at 6:30 p.m. for meet and greet; the demo will begin at 7:30 p.m. To attend, RSVP by September 23 via email to rsvp@editorslounge.com.
As always, the event is free and open to editors and other professionals within the production and postproduction community. AlphaDogs encourages guests to bring a beverage of their choice.
All Editors' Lounge events are held at AlphaDogs' headquarters: 1612 West Olive, Suite 200, Burbank, Calif. Directions can be found at www.editorslounge.com/rsvp_directions.html.
AlphaDogs founded the Editors' Lounge events in March 2003 to help professionals in the production and postproduction industries exchange ideas, discuss trends, and learn about new technologies. The gatherings provide an informal environment for discussion and allow editors to have their questions addressed objectively - without a sales pitch.
For more information, call 818-729-9262 or send email to info@alphadogs.tv.
Ulead ships updated MediaStudio Pro 8 video editing software
Ulead Systems, Inc., a 16-year industry leader in video, image, and DVD software, today announced it has started shipping Ulead MediaStudio Pro 8, the latest version of Ulead's professional video editing software. The new release offers a professional, yet easy-to-use, approach to video editing suitable for video enthusiasts, newly professional video editors, documentary filmmakers, wedding/event videographers, and media producers in corporate and education.
"Version 8 is the most significant upgrade in the history of MediaStudio Pro," said Lewis Liaw, president of Ulead Systems. "We listened carefully to what our loyal users want, and the result is a future-ready application with extensive HDV support, a streamlined workflow, and ground-breaking features such as the new Smart Compositor."
The new release incorporates a wide range of enhancements. Smart Compositor is a unique, all-new tool for quickly creating professional composited opening sequences or segues. A new single-track editing interface, Smart Proxy mode for efficient HDV editing, advanced color correction, and 5.1 surround audio editing all combine to make this the perfect package for professionals and enthusiasts alike.
Many of the new features in MediaStudio Pro 8 have their roots in user feedback and "wish lists" from user forum participants. A preview beta version of MediaStudio Pro 8 was released to the public three weeks before shipping, and the resultant comments in the user forums were overwhelmingly positive, with users praising the new intuitive layout and robust realtime HDV performance.
The box and electronic download versions of MediaStudio Pro 8 are available at $399.99 through retail channels and Ulead websites. Current MediaStudio Pro users can upgrade for $249.99, and users of VideoStudio and DVD Workshop can upgrade for $299.99, also from Ulead websites.
For more information on the company, its products and services, please visit Ulead's Web site at www.ulead.com.
Shining Technology brings direct-to-edit DV, HDV CitiDISK recorder to European market
Shining Technology, a leading provider of high-performance data storage solutions for the professional and prosumer digital video, video editing and broadcast markets, announced availability to the European market its new award-winning CitiDISK HDV, a high-capacity DV and HDV storage peripheral small enough to fit in the palm of the hand.
Weighing a mere 10oz., the FireWire-enabled CitiDISK HDV offers the speed, storage capacity and portable convenience of recording directly from camcorders into most NLE software packages with instant playback capability, thus eliminating the otherwise time-consuming intermediate step of recapturing video footage.
Despite its small form factor, CitiDISK HDV is long on storage capacity and, with its rugged design, is built for durability for the working broadcast, video, and editing professional in the field. CitiDISK HDV embeds a high-capacity laptop computer-grade hard drive (available in 40GB, 80GB, or 100GB models) with internal shock absorption cushioning (all around) for maximum hard drive protection.
With its ultra-fast FireWire connectivity, CitiDISK HDV users can record their video footage at continuous speeds of up to 12MB per second. In addition, the sustained device transfer rate is four times faster than recording speed. Depending on the selected video resolution, CitiDISK HDV can store between 1.5 and 7.5 hours of DV or HDV footage.
Optimized for both Mac and PC professionals and video editors, CitiDISK HDV records and organizes video footage into the user's choice of computer-recognizable file formats (.M2T, .MOV, .AVI, .DV, and others), and users can instantly play back, edit, review, and archive files. When done shooting, camcorders can be set to VCR mode to "QPLAY" the last scenes on the viewfinder or simply plug into the computer's FireWire port and edit/play directly on the digitized video at any time.
Providing users further convenience is the drive's "PLAYALL" feature, which allows pre-captured footage to be looped and can loop from the last scene captured and wrap from the beginning to the end in a forward direction - giving the users the option to toggle the scene selection backwards or forwards as they wish.
To give users maximum power sources without disrupting their workflow, CitiDISK HDV embeds a rechargeable Lithium Polymer battery that automatically kicks in when external battery power runs low. This seamless battery power changeover ensures non-stop shooting capability without needing to shut down the unit.
For more information, visit the company's website at www.shining.com.
Continue the discussion on Crosstalk the Millimeter Forum.