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Going Digital - Video |
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Digital video editing is far more complicated than using word processing programs. You have to know the technical stuff.
What is Digital or Desktop Video Editing? Digital Video Editing, or Desktop Video (DTV) Editing, is using your computer to edit videos. Today, computers are so fast and storage is so cheap that you can capture your video directly from your camcorder to your computer, edit it, add all kinds of cool titles, filters, transitions and FX. Then you can output back to tape, onto the web or even onto a CD or DVD. Although different technically, Digital/Desktop Video Editing is the same as Non-Linear Editing (NLE) for most practical purposes. What is Non Linear Editing? Non Linear Editing (NLE) is editing using random-access video storage. It means you can get access to your footages from hard drive randomly and instantly. The video files on your hard drive are just like normal Word documents, you can load, watch, manipulate, any part of the file in a non-linear mode. Instead of using jog shuttles and special video decks, you simply capture the video to your hard drive. You can then edit and rearrange the shots much like moving paragraphs around in your word processing program. Since the video is digitized, you can instantly get to any exact point in the video.Non Linear Editing software is timeline based. Each shot is placed on the timeline. You can lay down more than one track of video and audio onto the timeline.The best part about NLE is the effects. It's only limited by your own imagination and the software you choose. You can add special filters to clean up and restore picture quality, or to place ripples or swirls in the video. You can also create awesome transitions between shots.Then comes titling and graphics. You can use any Windows true type font, so foreign languages are no problem at all. You can add a logo or computer graphic or even animation. In fact, you can make it fly, bounce, or spin onto the video. You can also add cool plug-ins to your NLE software to create awesome 3D transitions and effects.The power of NLE is truly incredible. Now every video makers can create videos that look and feel like network productions. What is Linear Editing? In the past you had to edit linear. The simplest form of linear editing is called assemble editing or deck to deck. This is when you copy the "good" parts of a tape over to a new tape and repeat the same process until the whole program is finished. A/B roll editing is when you edit from two or more video sources. An A/B roll system often includes a digital mixer, to let you cut, fade, dissolve and wipe from source A to source B. Non-Linear is definitely the way to go. Anything you could do on an old fashioned linear system can be done better and cooler with NLE. The only instance you may have to use linear system is probably producing news programs where you have to finish it really fast and don't need any effects.
What is a video capture card? Video capture cards let you record video from camcorder or VCR onto your computer's hard drive. These cards use hardware and/or software compression (codec) to digitize the video onto your hard drive. While it is the video editing software that lets you actually create and edit the video, it is the video capture card that determines the quality of your video. Check out this comprehensive video capture card features chart to see which card is best for you. What is a CODEC? CODEC stands for Compression/Decompression. It is the compression algorithm used by your video capture card to digitize and store the video on your hard drive. Codecs exist for all kinds of compressed video, including DV, MJPEG, MPEG, Indeo, Cinepak, Sorensen, wavelet, fractal, RealVideo, vXtreme, and many others. The three most popular video codecs used today are MJPEG, DV and MPEG. Besides capturing video, the codecs also come into play when you need to render transitions, titles, and effects. The system has to take the source frames, decompress them, perform the effects, and recompress the resulting frames. What are "hard" and "soft" codecs? Hard codecs are hardware codecs, normally a computer chip. You supply power and raw video at one end, and get compressed video out the other end in real time. Flip a switch and pump in compressed video, and raw, uncompressed video comes out. Soft codecs are software modules that do the same thing, such as the DV codecs supplied by QuickTime or Microsoft. Modern computers are fast enough that soft codecs can compress or decompress in real time or even faster.
Which is better, hard or soft codec? One thing to keep in mind is that "hard" vs. "soft" doesn't matter when it comes to video quality, both give excellent result when working properly. Speaking of speed, in early 1998, various vendors claimed a 25% or 30% speed advantage of hard codecs over soft codecs. Too much depends on other factors, like the speed of the computer's CPU, bus and bus interface chipset, to decisively say that one codec will be faster than the other in effects rendering. As CPUs and buses speed up over time, the soft codecs have taken the lead in speed for rendering operations. However, hard codes do have some advantages sometimes depending on your requirements. Hard codec systems usually come with breakout boxes that include analog (composite, Y/C, or even component) connections as well as 1394 connections. You can connect up any VTR format with analog I/O to the box and capture it in real-time or output to it in real-time. Another very cool feature that many hardware based capture cards now have is real-time features such as transitions, FX, filters, titling and more. You do not have to render, these effects play directly from the timeline. Not everything is in real-time with these cards. Each real-time card comes with its own special selection of real-time features. What is FireWire? Also known as IEEE1394 or iLink, FireWire is a new interface standard that allows super high speed data transfer. It is the hottest new technology in digital video. When you use a DV camcorder/VCR and FireWire card, the video is passed directly from your camcorder to your hard drive. Because the signal stays digital through the entire process, you get zero loss and a final video with identical video quality to the original footages. For more information about FireWire and DV, see DV & FireWire FAQ. What is Rendering? Normally, before your edited video can be played back to tape, the computer have to "render" or "make" the finished movie as a single separate video file. Once this new file is created, you can play it back anytime you like. The rendering process takes up a lot of computer power and time. The more titles, effects and filters you add, the more processing power, speed and time will be needed to create the finished video. This is the area where more RAM and a faster processor can really make a difference. Rendering can take 10 to 20 times as long as the total time of the finished movie. Rendering times of several hours are not uncommon. Until rendering becomes faster, long videos (over 1/2 hour) with effects are not very practical even for professional editors. What is full speed, full screen video? A standard NTSC video signal consists of 30 frames (actually 29.97) per second, and two fields per frame. This is considered to be full speed or full motion video. PAL uses 25 frames per second.With digital video, full screen is considered 720x480 for NTSC, 720x576 for PAL. If you capture at a smaller size, your computer will have to interpolate the missing information when it plays back the video full screen to your VCR or TV. The larger the capture size, the higher the resolution, and the greater size of the file created. What additional equipment do you need for NLE? Besides computer, you will need: A video capture card to digitize and output videos Editing software to create all the amazing effects Lots of extra storage space for video clips Most capture cards can be purchased as bundles with NLE software included.
How much hard drive space do you need? Simply put, you will need a lot. The higher the resolution you need, the more space the video will require. Fortunately, hard drives are getting faster and cheaper. For DV footages, you'll need 13GB per hour of raw video. If you plan on doing DVD authoring, you'll need the same amount of space for that. For the best results and highest video quality, you need a dedicated video storage. This can be a big, fast EIDE ATA66/100 drive for basic DV editing, or a Medea VideoRAID, SCSI drive or Promise FastTrack RAID for long format real-time productions.
What is Timeline Playback? Timeline Playback technology has been implemented by most of the leading hardware/software vendors. This new technology allows you to play video directly from the timeline. All transitions and effects are rendered into temp files and then the entire video is played out without rendering a new, second video file. This also decreases the time required to render the new video file dramatically if you really need to create a separate file.INSTANT video, Power Play and Cut List, as different vendors call it, are all basically the same thing, timeline playback.
What is Real-Time NLE? Real-time NLE means that you can play video directly from the timeline and that the transitions, filters and effects do not have to be rendered. Since you do not have to render, these systems save you both time and disk space. Real-time technology is a combination of hardware, software, special drivers and the speed and power of your computer. The most important factor is the capture card. Not everything in real-time cards is real-time. Each real-time card comes with its own special selection of real-time transitions and effects. Some of the newer, less expensive cards offer real-time output for analog, but require rendering for DV/FireWire output. The effects and transitions you get that are real-time will vary from product to product, depending on how the engineers have implemented their real-time technology. These cards do have specific hardware requirements. If you add enough layers, filters, effects, and titles, you'll exceed the system's capacity for real-time performance. But don't worry, there won't be anything funny. The system will just have to render some parts of the video before playing it back.
What are plug-ins? Plug-ins are additional software programs that add extra features and effects to your NLE system. They are called Plug-ins because they "Plug In" to your NLE software and operated as if they were a part of it. Typically, a plug-in will appear and function just as other original features of the NLE software. For example, a 3D transition plug-in would appear as one of the listed transitions in the transition library.
How do I put my video clips on the web? That depends on how you plan on delivering the clips to your audience. If you want your visitors to download the clips before viewing, you can export the clips using any codecs and put it on the web just as normal downloadable files. This way, you can provide high quality videos to your audience. Choosing the proper codecs is the most critical task for this method. Also you need to test and set the resolution, frame rate and compression rate carefully to limit the file size and download time. In addition, you have to make sure that your audience have the same codecs to decompress the video. If you want to stream video on the web, you've got to compress it into one of 3 formats:
All three of these formats have strengths and weaknesses. Streaming video technologies like RealPlayer require special servers and software. Also special HTML coding is often needed. Either way, the key to good web video is to start with high quality video. Although the video will be squeezed down to fit over the nets limited bandwidth, the more data you give the compressor to work with, the higher quality the finished product will be. Digital video editing is far more complicated than using word processing programs. You have to know the technical stuff. What is MPEG-2? MPEG2 compression is what Hollywood uses when they make a DVD. MPEG2 video quality is scalable, and it can be just as good or better than DV. It is a much more efficient compression than DV or MJPEG, so you can maintain video quality at 1/2 the data rate!! We are on the brink of a video revolution that is going to make digital video production easier, faster and less expensive. MPEG2 is the first video compression that supports non-linear editing for all formats of video. VHS, 8mm, Hi8, SVHS, DV, DVC Pro on up to broadcast quality. The only drawback to MPEG2 is that its file structure makes it much more difficult (and therefore expensive) to edit. That is why so many of our DV NLE systems now allow you to export MPEG2 files for DVD authoring, but very few will let you edit MPEG2. Once you have MPEG2 video files, they can be put on CD-ROM, Video CD, and DVD or you can stream it over the Internet. It looks like it's going to be the Holy Grail of digital videography. All that's been missing is an affordable way to burn DVDs.
What is MPEG-1? MPEG-1 has been a good choice for creating multimedia or web based video. Unlike MJPEG, MPEG-1 is designed to pack a large amount of good quality video into a small file. Current versions of Win95 include an MPEG-1 player, so any one can take your MPEG-1 files and play them on their computer. This makes MPEG-1 ideal for creating video CD ROMs and multimedia. Why is digital video compressed? Digital video is compressed because it takes up a staggering amount of room in its original form. By compressing the video, you make it easier to store. Digital video can be compressed without impacting the perceived quality of the final product because it affects only the parts of the video that humans can't really detect. |
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