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by Dick Oliver
So you think you want to create some video for the Internet. The first question to ask yourself is "Do I really need video, or can I create a similar effect using gif animation, client pull, or a multimedia authoring program like Macromedia Director?" All of these approaches are usually much faster and easier, both for you and the people who will visit your Web site.
Likewise, ask yourself, "Which would be more effective for the amount of space required: a few seconds of video, or a slickly produced audio piece replete with sound effects and music?"
When you are sure that video is the best or easiest thing to use for the task at hand, the question becomes "How much and what kind of video will best suit the requirements of my intended Internet site?" For example, imagine you are designing an online demonstration of the inner workings of the pistons of an engine. In this case, you could set the video to loop using Movie Player, which would allow you to run your presentation indefinitely in the space of about 100 K or less. Likewise, perhaps your movie will be almost as effective, or more effective, in 1-bit or 4-bit rather than 16-bit. Often, you can cut your frame rate and playback size and still create the effect you are seeking. Remember, people have to download your clip, and in most cases users will happily trade some quality to have the clip quicker.
Moreover, most people will simply not be able to enjoy high-quality video-even if they don't mind the download-because they do not have enough video RAM to display at color depths greater than 256 colors, or a processor capable of pushing large, high-quality video images.
All this is not to suggest that you should avoid video, especially if you want it or need it. Nor is it to suggest that the average user cannot enjoy beautiful video created by you and transmitted over the Internet. The real issue here is to determine how to create the best effect for the least bandwidth.
For example, a stark black-and-white image is not only far easier to download, but in many cases it is far more compelling than any color version of the same thing-in much the same way that a black-and-white movie is often more enjoyable than a colorized version of the same motion picture. Would Charlie Chaplin or Orson Welles be as powerful in color? Imagine further the riveting photographic images of Ansel Adams or Richard Avedon-they simply would not have the same dramatic impact if they were in color.
Before deciding how to create the desired video, one should look at the tools that are at hand and what effect is desired. Ideally, what you create will be a match between the tools and the concept. In many cases, you will have to be clever in fashioning your concept to match the tools you have available to you in order to create the most powerful effect.
Unless you plan to reuse digital video from another source, the first thing you'll need to do is to get a camera. You can easily rent video cameras in most cities, but if you want to invest further and purchase a video camera for creating your own video movies, we suggest selecting a good Hi-Band 8 video camera with a plug-in for an external microphone.
Although Hi-Band 8 is not quite broadcast quality, it is substantially better than Regular 8 or VHS. When you digitize the video, the difference in picture quality between Hi-Band 8 (about a thousand dollars) and professional equipment (about 10 thousand dollars) will be nonexistent.
When choosing a Hi-Band 8 camera or other video camera, camera sensitivity is one of the most important factors to consider. The camera sensitivity is measured in lux, which means the light level at which the camera is able to pick up images. Most Hi-Band 8 cameras can shoot down to about 2 or 3 lux. The lower the lux, the darker the environment you can successfully videotape and thus the less will be your need for cumbersome lighting equipment.
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The cheapest method of all may be to use the Connectix camera. These little color cameras cost only $199 (including all hardware and software you need to get started) and are available for both Mac and Windows. The camera can be used for video teleconferencing (software and instruction for teleconferencing available at http://www.wpine.com/ins.html) as well as capturing live video-but, of course, this is not a real-time capture, so do not be disappointed. The Connectix camera captures sound video in full color and works well in low light situations. The only drawback of the camera is that it needs to be connected to a computer, but if you want to go mobile, you can connect the camera to a notebook computer (either Mac or pc) and shoot your own version of Citizen Kane on location. The software included with the Connectix camera doesn't enable editing, but it does provide a variety of effects and frames for video playback. For $199 this little camera is hard to beat. More information on the Connectix camera is available at the http://www.connectix.com/ Web site. |
As any video producer knows all too well, there are many, many factors that go into a successful video shoot-more than we have room to cover in this book. But for the two- to ten-second clips that are currently viable for most Web uses, the lighting and choice of subject matter will matter more than anything else. The subject matter is, of course, up to you, but we can offer a few tips on lighting that can make a dramatic difference in the quality of your video.
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One quick note to those who wish to digitize home movies or 16 mm films for playback on the Internet using a projector and a video camera. You will need a five-blade projector. A five-blade projector has the same shutter speed as a standard video camera. If you do not have a five-blade projector (you probably don't-most are four-blade) and try to digitize anyway, your videotaped image will appear to strobe and the video will be unusable. If you are not sure, you can try it and see, or open your shutter gate and make a small mark on one of the blades (located behind the lens) and count the number by turning the mechanism manually. Five-blade projectors are available for rent at most A/V rental houses, or they can be purchased for about two hundred dollars through an industry magazine called The Big Reel. You can also have your home videos transferred to videotape at many photo labs, such as Fox Photo. |
Good lighting and careful planning are essential for a successful video shoot, no matter how good your equipment is and no matter how low a lux your camera can handle. There are numerous books on video lighting and production at any public library or camera store. You can also check out the Videomaker's Glossary of Terms at http://www.videomaker.com/edit/other/glossa~1.htm.
All of these resources will emphasize the same basic lighting triangle, which consists of three lights arranged in a triangle around your subject. The three lights are as follows:
After you have successfully lit and captured a scene using a video camera, you must digitize it into the computer. This process varies, depending on the hardware and software you use on your computer. For instance, if you are using an Apple Macintosh computer with Audio/Video capabilities, you may simply connect your video source to the computer and begin recording the content digitally. If, however, you are using a pc, you first must purchase a video-capture card. These cards range from a few hundred dollars to several thousand dollars, depending on the level of quality you are striving to obtain. Obviously, the most expensive cards are intended for video professionals who are creating digital studios with their computers. However, the price of typical capture cards has dropped below five hundred dollars.
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When shopping for a video-capture card, make sure that it is capable of digitizing motion video. There are numerous devices on the market today that accept a video signal from a source such as a video camera, but merely take a single unmoving "snapshot" photo from a moment of video. This photo can be useful for making still images to put on a Web page, but won't allow you to put moving video onto a Web page. |
Most capture equipment includes software for capturing video input. Adobe Premier, Microsoft VidCap, and Video Action Pro (registered version) all offer the capability of recording digital video. Most programs enable you to specify the format of the video file that will be captured. You may choose settings such as the following:
Although you will ultimately wish to create a video that is highly compressed so that it requires very little space, capture your original footage using the highest settings possible. Then, when you are editing the footage with other material, you can be sure that the final, compressed video will be as clear as possible. If you use a high amount of compression when initially recording, those compressed files will be further compressed when they are edited and used to produce another final file. Be aware however, that minimizing compression during the recording process will generate mammoth files.
Figure 24.1 demonstrates a video capture in progress, including the numerous option windows that VidCap provides. You may capture video using any number of settings. To conserve space and transmission times, Internet videos should be relatively small in dimension with low-quality audio and high video compression.
Figure 24.1 : A VidCap video capture in progress.
To begin recording video content digitally, simply start the recording software. In the case of Figure 24.1, Capture Video Sequence was chosen from the Capture menu. When all settings have been verified, clicking on the OK button starts the recording process. Logically, pressing the Esc key on your keyboard halts the recording process.
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Because it takes a moment to actually start the process, start recording first and then begin the actual video signal output. Although you may record either video noise or blank input, you can be sure that you will not miss the introduction of the video clip. You may always use video-editing software to remove those blank sections of your video file. |
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If you do use VidCap to capture your video files, it is important to remember to set the capture file each time you wish to record. This may be accomplished through the Set Capture File option in the File menu or by clicking on the left-most toolbar button. Setting the capture file allocates space for recording the digital video. However, if you forget to reset the capture file, you may inadvertently overwrite your previous work. |
After you capture your video, you will need to edit it. There are many different editing packages available-too many to examine in depth in this book. If you already have a video capture board, it was probably bundled with an editing package. Most video-editing packages are fairly similar, unless you are using a very low-end package or desire elaborate effects. For those wishing to explore creating more elaborate videos, you may consider using more advanced software such as Adobe Premier.
If you are a Mac user with only the Connectix camera, or with only a video-capture board and no software for editing, try QuickEditor-a low-cost shareware movie editor. It is Mac and PowerMac native and offers features including 2D and 3D plug-in transitions and effects and stereo soundtrack editing. QuickEditor is available at ftp://sumex-aim.stanford.edu/info-mac/_Graphic_%26_Sound_Tool/_Movie/.
As an example of the steps involved in digital-video editing, this section shows you how to create a simple video production using Video Action ED for Windows-based machines.
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Video Action ED was chosen to demonstrate video editing because it is the only full-featured video-editing program available for under $30. This makes it a good choice for Internet work, where a $595 program like Adobe Premier is definitely overkill. You can get Video Action ED, along with a complete 3D graphics and animation package on the Videology 3D CD-ROM from Andover Advanced Technologies, Inc. (http://www.andatech.com/), or free with the Sams.net Publishing book Web Page Wizardry. Andover Advanced Technology also offers a more advanced video-editing and special-effects program called VideoCraft, priced at $99. See their Web site at http://www.andatech.com/ for details. Regardless of which video-editing software you choose, the basic steps in the following discussion of video editing will be essentially the same. |
When you first start Video Action, you will be greeted with two windows: a timeline in the top half of the Video Action window and a gallery in the lower half. A timeline or storyboard is common to almost all video editing software; it enables you to position elements such as video, audio, or pictures at some exact moment in time. When the final movie is played, the items placed in the timeline will be played in the order in which they appear from left to right.
The gallery is a collection window that displays all of the multimedia content currently in use for the final video production. Figure 24.2 displays a Video Action screen, in which the order of videos and transitions may be found in the timeline window at the top. The original video, a static bitmapped file, and an additional audio file may be found in the gallery window at the bottom of the screen.
Before you can place any multimedia elements on the timeline, you must first import them into the gallery window. To do this, you can simply click on the small button in the top-left corner of the gallery window (this button appears as a pot with four colored balls and an arrow pointing into the pot). You may also select the Collect command from the Organize menu when the gallery window is active.
No matter how you do it, a dialog box will prompt you to select content to import. Simply select the bitmaps, videos, or audio files you wish to import and click on the OK button. The items you have selected will then appear in the gallery window at the bottom of the Video Action window. A small thumbnail drawing of the original item will be displayed as well.
After you have imported the content necessary for your video production, you may begin dragging the items from the gallery onto the timeline. You may drag graphical material on any of the four video tracks or audio material on any of the four audio tracks. After you have dropped a video or graphic item on the timeline, it will be represented by a yellow rectangle with a thumbnail of the content. The length of the yellow regions on the timeline are directly proportional to the length of the actual clip.
Similarly, you may drag audio resources from the gallery onto the timeline. These files will appear as light blue regions in the audio tracks of the timeline. You may place either type of resource anywhere on the timeline. If audio and video clips overlap in the timeline, they will be played together. Any blank space in the timeline indicates silence in the video, represented by muted audio tracks and simply a black screen in the video tracks.
Let's assume you had three video clips that you wanted to play immediately after each other. Let's also assume that you have a single audio file that is long enough to span the length of the three video clips. To create a final video, you simply drag the three video clips onto one track in the timeline, ensuring that the beginning of each subsequent clip lines up with the end of the preceding clip. The audio file is then dragged onto its own audio track, such that the beginning of the audio file lines up with the beginning of the first video clip.
As mentioned earlier, it is possible that you may record signal noise or "blank" frames before or after the actual content you intended to record. The starting and ending positions of each video clip identified on the timeline may be adjusted. To adjust these settings, double-click on a clip in the timeline. A window similar to the one shown in Figure 24.3 is displayed.
A preview of the clip being modified is available in the center of this window. Beneath this preview is a scrollbar that enables you to seek a specific frame in the video. Just beneath this scrollbar is a range marked by a yellow line with two red end points. This range identifies how much of the clip is being used in the timeline window.
If you find that you need to trim the beginning of the video clip, simply drag the scrollbar to the new starting position for the video clip and click on the "Time In" button. The range that identifies the video clip will be adjusted appropriately. These "Time In" and "Time Out" buttons simply enable you to specify where you want a video clip to begin playing and where you want it to stop.
There is nothing wrong with placing video clips right up against each other on the timeline. The clips will be played in the final movie production, but will there will be no transitions between them; when one clip is finished, the second will immediately appear. Although this is not unacceptable, there may be occasions when you prefer to create a smoother transition. For example, if you had one clip that was dark and another that was bright, playing those clips back-to-back would create a flash between the dark and light clips. Depending on the effect you are trying to create, you may prefer one clip to transition gradually into another via a dissolve effect.
Let's create a dissolve transition in Video Action, using the three back-to-back clips discussed earlier. Between the first and second video tracks in Video Action, there is an additional transition track. This transition track specifies which transitions are to occur between the first and second video tracks when the final movie is rendered. To create a transition in this track, simply drag one clip to the second video track so that the beginning of that clip starts before the clip on the first track finishes. The transition effect, indicated by a green region in the timeline, will be created automatically between the time in which the second track's video clip starts and the first track's video clip ends. The timeline window in Figure 24.2 includes five separate transitions for the movie being created.
When you have defined the transition region, you may then specify which transition you wish to use between the video clips on the first and second video tracks. To change transition effects, click once on the transition you wish to alter in the transition track. Then click on the Transition menu to display a Transition Group window. This window enables you to select from 20 different transition types including: wipes, dissolves, zooms, and even page-turns. Double-clicking on the appropriate animated icon replaces the selected transition with the new effect and displays a Transition Viewer window, as shown in Figure 24.4. This transition window enables you to modify specific properties regarding the transition or preview how the effect will appear in your movie.
If you wish to create a second transition, you will need to place the starting position of the third video clip just before the end of the second video clip. This time however, you must place the third clip back on the first track. Because the transition track is applied between only the first and second tracks, all video clips that are to be included in a transition must exist on either side of the transition track.
Video Action-like all other major video-editing programs-enables you to incorporate special effects into your own digital movies. Some special effects are absolutely legitimate and necessary. For instance, if you digitized a video clip and the lighting was not suitable, you could adjust the brightness or contrast of the clip and save the modified version in your final movie. Yet there are also several cool effects such as Old Movie, Kaleidoscope, Star Highlight, or Title Generator that can make your movies stand out.
To add a special effect to a video clip, first select the video clip in the timeline window. Then choose the Video Effects & Titler option from the Tools menu or click on the FX button on the toolbar. A window similar to that shown in Figure 24.5 is displayed, enabling you to select special effects and tweak the results of each effect.
When you have finished designing the timeline for your digital movie and are satisfied with the layout, you may create the final movie. To create the movie in Video Action, you must first specify the settings for the final production. Settings for the final movie may be altered by selecting Movie Settings from the Movie menu while the timeline window is selected. Figure 24.6 is an example of some of the settings that may be modified for video files being created.
When creating Internet videos, remember to keep the size of the final video file relatively small. Smaller files require less time to transmit over the Internet and are therefore more effective for the person viewing them. You can adjust the settings in the Movie Settings window to achieve optimal compression by doing the following:
After you have established the appropriate settings for an Internet video, you must select the region of the timeline you wish to export as the final movie. A yellow bar with red triangles at each end of the bar and the word Movie on it should be present near the top of the timeline window. Simply stretch the ends of this rectangle to enclose the multimedia elements in the tracks below. In other words, ensure that the beginning of the Movie meter is at the same position as the beginning of the very first video clip. Similarly, make certain that the end of the meter is at the same ending position as the last video clip.
To create the final digital movie, select Make Movie/AVI File Output from the Movie menu. When a dialog window appears prompting for the name of the final movie file, type in an appropriate name and click on the OK button. All of the content in the timeline window will then be assembled appropriately and written to a final .avi file.
How your video picture looks and how long it takes to stream across the Net will be largely determined by which video codec you choose when compressing your video clip. Codecs (short for compressor-decompressor) compress the enormous amount of video information needed to display a video movie on your computer. When the user plays your video, the codec decompresses the video on the fly while the movie plays back.
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A quick lesson on digital video: Most digital video must be compressed in order to be stored with a reasonable amount of space. Then when the stored video is played, the data must be decompressed in order to be displayed. For example, a 320 ¥ 240 pixel video clip with 24-bit color depth and a frame rate of 15 fps would take up just under 3.5 M of space for just one second of video without compression! Several companies, such as Intel, Cinepak, and Microsoft, have designed digital-video compression technologies-each with varying quality and amount of storage space saved. These compression/decompression techniques are accomplished using software, but there several hardware-based codecs as well. MPEG (Motion Pictures Expert Group) is an example of a hardware-based compression/decompression scheme. |
Codecs can be lossy, meaning various areas of the picture are simplified, or lossless, meaning all areas of the video are kept intact. Lossy codecs have lower overall quality but offer much greater compression than lossless codecs.
There are numerous different types of codecs available, both hardware- and software-based. Although hardware-based codecs offer far greater compression, they also require the user to have similar hardware for playback; software-based codecs require only similar software (which is usually free). Consequently, because the Web is worldwide and very diverse, we will cover only software-based compression solutions.
MPEG (software-based version) is the most commonly used type of compression on the Internet-first, because freeware MPEG converters are commonly available on the Web, and second, because MPEG offers the best compression ratio of any commonly used codec.
However, MPEG does have the disadvantage of being lossy and not allowing 8-bit compression. Although 16-, 24-, or even 32-bit video is great, most computer users cannot display it properly. Consequently, the quality of MPEG is substantially degraded for many users. Another disadvantage of MPEG is that most of the freeware converters on the Web do not offer a facility for playing back audio along with the video image, although MPEG-1 can support audio and video tracks. MPEG-2 is designed for commercial-broadcast applications and is not currently applicable to Web-based applications.
Cinepak is the most commonly used video codec for CD-ROM production. Cinepak, although lossy, offers very good compression and enables you to embed an 8-bit palette within a 16-bit or 32-bit movie. Embedding an 8-bit palette within your movie significantly improves the visual quality of your video when played back on a computer unable to display at higher color depths.
The biggest drawback of Cinepak is the significantly longer time it takes to compress the video. Typically, Cinepak takes between 30 seconds to 2 minutes per frame to compress a piece of video footage. Thirty seconds of video, captured at 10 frames per second, could take as long as 10 hours to compress.
Indeo R.32 (which stands for "release 32") is similar to Cinepak and is rapidly replacing it for CD-ROM production. Although lossy, Indeo offers good compression and enables you to embed an 8-bit palette within a 16-bit or 32-bit movie. Embedding an 8-bit palette within your movie significantly improves the visual quality of your video when it is played back on a computer unable to display at higher color depths. Indeo's 8-bit playback quality is substantially higher than that of Cinepak, and Indeo R.32 also compresses substantially faster than Cinepak.
In comparison to Cinepak, Indeo R.32 does have a few disadvantages. Cinepak offers slightly smoother playback at high frame rates and slightly better compression. Indeo R.32 is available at http://www.intel.com/pc-supp/multimed/indeo/.
Indeo Video Interactive is perhaps one of the most exciting new codecs available. According to Intel, Indeo Video Interactive offers new features, including:
As was the case with Indeo Video release 3.2, Intel continues to license Indeo Video Interactive to software developers for free and on a royalty-free basis. Indeo Video Interactive is available for both Mac and Windows platforms, and offers better compression than earlier versions of Indeo. It is available at http://www.intel.com/pc-supp/multimed/indeo/.
Animation compression (lossy) offers decent compression and fairly good playback speed with the added advantage of color depth settings ranging from 1-bit to 32-bit color or black and white. If the material is appropriate, a 1-bit or 4-bit video clip can produce stunning results and substantial file-size savings using the animation compressor. For example, Expressionist motion pictures such as Nosferatu or the Cabinet of Dr. Caligari would translate nicely using a 4-bit black and white compression. Likewise, animations such as a typical Charlie Brown special would drop down to 4-bit color fairly successfully (see the section on DeBabelizing video later in this chapter). Many animated logos could drop down to 4-bit color with this process, as well.
JPEG (lossy) compression, although offering incredible compression ratios, decompresses so slowly that this method is rendered almost useless for anything other than a slide-show style presentation. Like MPEG, it does have the disadvantage of being 32-bit based and is often extremely lossy.
Graphics compression is lossless and offers the major advantage of giving the user the option of creating a custom palette for 8-bit video. When displayed in 256 colors (if you DeBabelize your video), the picture quality is perhaps the best of any codec. However, graphics compression and decompression rates are so poor that it is hard to achieve an adequate frame rate.
With all of the preceding codecs, you will be given a choice of frame rate. With many of them, you will also be given a choice of quality. (It is best to capture at the color depth and frame rate you plan to use for your final output.)
The quality and frame rate settings you choose will probably depend upon the content of your clip. For action sequences, you will probably want to choose a higher frame rate and lower quality. Otherwise, in an action sequence, the jerkiness caused by a low frame rate would be more noticeable, whereas the image improvements from the high-quality setting would not even be noticed (so trade these two options, as first stated, for best effect).
For nonaction sequences, choose the exact opposite quality and frame rate settings than for action sequences. A lower frame rate, but with a higher quality setting, is appropriate-jerkiness will be less noticeable, whereas artifacting will be far more noticeable.
The best way to ensure a high-quality video for the majority of users is to do what most multimedia folks call DeBabelizing, after the popular Macintosh video processing program named DeBabelizer. This program enables you to process video and graphic files in a number of ways as well as import and export using a multitude of file formats.
In this section, you will see how it is important to create a common color palette to be used throughout your digital video. For instance, by optimizing your video to be used with the default colors of the system palette, you can use your video files neatly with other graphics. If you do not perform such a process, machines with lower color resolutions such as 256 colors may constantly remap colors in the system when playing video content. This may cause adverse color effects in other programs in the rest of the system.
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Windows 95 has made significant improvements in this area, attempting to resolve color resolution problems and color mappings automatically. However, if you wish to control the color output of your video files on a Windows-based machine, you may use Video Action ED. In the Movie Settings window you may specify which compressor to use when creating a final video. If you instead choose No Compression for the compression option, the color depth option then enables you to choose from several palettes (including custom palettes) when rendering the final movie. Similar settings can be specified in Adobe Premier and other video-editing software. |
The DeBabelizing process polls the frames, looking at each of them to count and notate the colors contained in each. Then it compares all of the colors used in the movie and picks the best 256 colors to represent the millions of colors contained in that exact movie. This Super Palette can be embedded in movies made for QuickTime 2.1 or higher. (QuickTime 2.1 is available free of charge for both Mac and Windows from Apple Computer at http://www.astro.nwu.edu/lentz/mac/qt/).
When the movie is played back in 8-bit, QuickTime calls up the palette and resets the monitor temporarily to that color palette, which eliminates much of the graininess of 8-bit playback while not affecting the playback quality of the movie at higher color depths, such as 32-bit. It is possible to do this using both Indeo and Cinepak, but Indeo does a far superior job.
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Although the Graphics compression setting does a better job of rendering an 8-bit palette than either Indeo or Cinepak, it requires that you remap your movie to the 8-bit palette, resulting in an overall poorer quality at higher color depths, a significantly poorer quality of encode and decode, larger file sizes, and poorer playback. |
The best solution possible when size is the determining factor? If the movie is a color movie, use Cinepak with a DeBabelized 8-bit movie. This has only recently become a possibility. (Note: You will need QuickTime 2.1.)
By reducing the color depth of your movie to 256 colors, you will be able to reduce your compressed movie size by about two-thirds (as compared to a 24-bit version of the same movie). Follow these steps:
Figure 24.14: Some advanced options may be set for the Cinepak code.
DeBabelizer now generates an 8-bit Cinepak movie. The time it takes will depend upon the size of your movie, but it will take approximately twice as long as it took to poll the color information and create the Super Palette.
This chapter has given you a quick crash course in creating digital audio and video suitable for the kind of uses you saw in Chapter 22, "Adding Multimedia to Your Web Site." In Chapter 25, "Adding Interactivity with Shockwave for Director," you'll learn how to take visitors to your site beyond passive listening and viewing, into the new world of interactive media.
