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Videoguys Home Page > DTV Handbook > NLE Primer
First lets start with the easy answers:
Before we begin to discuss Non Linear Editing (NLE), let's go over what good old fashioned Linear editing is all about.
Today, linear editing means deck to deck. The quality of your linear editing is dependent on the editing capabilities of your decks. For the best results you need special editing decks with flying erase heads, special editing jacks, pre-roll and time codes. These decks often cost $1000 or more.
The best part about NLE is the effects. Since the video is in digital form, we don't have to worry about time base correctors and frame synchronizers. Our effects are only limited by our own imagination and the software we choose to use. We can add special filters to clean up and restore picture quality, or to place ripples or swirls in the video. We can create awesome transitions between scenes such as page turns, flips, roll ups, and breakaways, plus the standard dissolves and wipes.
You can also add cool plug-ins to your NLE software to create create awesome 3D transitions and effects, like having the video spin into a ball or having moving video on all sides of a rotating cube!! You can morph one image into another, just like in commercials and music videos!
You can even add multiple titles, filters and effects onto the same scene. The power of NLE is truly incredible. Now every videographer can create videos that look and feel like network productions. The video you can create using our video capture cards and software will have your audience cheering, with everyone wanting to see more and asking how you did it.
The most important fact about the DV CODEC is that DV in = DV out. Since the video is transferred to and from your camcorder digitally via FireWire, there is no compression loss. Today with a DV cam or Digital8 and one of our FireWire cards you can produce broadcast quality video that looks as good as the original footage.
The IEEE1394 standard allows super high speed data transfers. The CODEC used is very similar to MJPEG, with less loss. It is roughly equal to 5:1 compression or a data rate of 3.7 megs/sec. The DV video compression is fixed, it is not scaleable. You can't lower the screen size, change the screen size or data rate. But don't let the relatively low data rate fool you. DV video looks as good as MJPEG video at data rate over 5 megs per second! One of the biggest advantages of having a fixed data rate of 3.6 megs per second is that sustaining it is a breeze for todays screaming fast computers. In fact with a PII 350+, 128 megs SDRAM and a big 10+ GB UltraDMA drive you can add one of our inexpensive DV capture cards and edit.
If you want to learn more about DV, we've got a ton of great info in our FireWire Q&A.
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.
A few years from now, we may look back at the Summer of '01 as the beginning of the DVD revolution. New DVD burners from Pioneer, Panasonic, Philips & others are starting to hit the market, with retail prices under $1,000!!! By January of 2002 these same drives are now under $500!! This could mean the beginning of the end for video tape and the transformation of video from a linear medium to one of random access. Just imagine having all your video archived on CD or DVD. If you want to find all the clips of the family dog, you just pull them out of the index. Want to skip from the baby being born straight to the first home run she hit in little league? No rewinding, fast-forwarding or searching. Every scene is indexed and just a click of the remote or mouse away. We can see the future of video, and tape
is not in it!!
The big decision you have to make with MJPEG is the size/compression/quality trade off. We consider
SVHS quality to be full screen capture, 30 frames per second, both fields at compression ratios lower than
6:1. At this rate you will get a little over 5 minutes of video (with stereo audio) per gig. Video at this quality
requires hard drives that can sustain data throughput over 3.5 megs per second. Professional SVHS video requires compression below 4:1, requiring data rates of 4.5 megs per second or higher!
Yes, you can edit video using your computer.
Now that we got that out of the way, let's find out what Non Linear Editing is all about and what you really need to get going. By the time you finish this page you will have a good background and understanding of the technology. Hopefully, if I did my job right, you will also be left with a burning desire to start doing it!!
Yes, the video can look as good as the original footage.
Yes, you can add incredible effects, transitions and titles.
No, you don't need to invest $3,000 or more.
No, you don't have to be a computer genius to install it.
No, you don't have to have a super powerful computer.Linear Editing
Most of us are familiar with linear editing. The simplest form of linear editing is called assemble editing or deck to deck. This is when you copy only the "good" parts of a tape over to a new tape. Assemble editing systems often include titlers (character generators) or special effects generators to make the videos more fun to watch. A/B roll editing is when we edit from two or more video sources. An A/B roll system often includes a digital mixer, to let us cut, fade, dissolve and wipe from source A to source B. Insert editing is when we splice in a different scene, or video only, into the middle of an existing video tape. Only very expensive, high end editing decks are capable of insert editing.Non Linear Editing
When we use the term NLE, we mean editing video from your hard drive. NLE requires two things: editing software and a video capture card to get the video into your computer. Once the video clips are digitized and on your hard drive they can be assembled in any order, with the drag of a mouse, much like moving around sentences in a word processing program. 
Non Linear Editing software is timeline based. You start by selecting the in and out points of your scene. Remember, that since everything is digital, we can get frame accurate edit points every time! Each scene is then placed on the timeline. You can lay down more than one track of video and audio onto your timeline. If you want to set your video to music, you start by placing the captured sound file onto the timeline. Next you select and arrange all of your video scenes. You can move scenes and clips around in your video just by dragging them with your mouse. It really is that easy!
When it comes to titling and graphics, NLE lets you go crazy. You can use any Windows true type font, so foreign languages are no problem at all. Want to add a logo or computer graphic you designed onto your video, it's a piece of cake. In fact, we can make it fly, bounce, or spin onto the video. Of course all our titles and graphics can be superimposed and mixed with our video.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.
Video Capture
Our video capture cards use various compression methods, called CODECs (COmpression/DECompression), to digitize and pack the video onto your hard drive. It is very important that you select the correct compression method to support your final video production. In today's world of digital videography it is important to realize that there is much more than old fashion video tape to deliver your content. 1.DV
2.MPEG2
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!! 3.MJPEG
Back in the 90s, if you wanted to edit video, your best choice was an MJPEG based video capture card. MJPEG does a good job, but it is considered a "lossy" CODEC, so the lower the compression, the larger the file size, and the higher the video quality. 640x480 is considered to be full screen capture. This results in the best quality video. MJPEG cards often support 1/2 or 1/4 screen capture as well. These formats are good for multimedia or VHS editing because you get more video per gig. The downside of these smaller capture sizes is that the card ends up having to recreate the missing info so you can end up with artifacts and blurred colors. 4.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. It is a low loss compression method. Best of all, today's multimedia Pentium can play back beautiful full screen, full motion video on your computer monitor. 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. Using MPEG-1 you can pack over 10 minutes of VHS quality video onto a single 100Mb zip disk! 5. Web Streaming
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. The biggest problem with web streaming continues to be bandwidth. Lets face it, the video looks much better with a high speed DSL or Cable modem than over 28.8 or 56k. Until we become a broadband internet, you will always have to make compromises between video quality, frame rates and bandwidth. So toady, for the best possible web streams, it is often necessary to create multiple versions of your clips, using the 3 different compressions at various connection speeds.
Compression ratios, data rates and minutes per gig at various video quality levels . | |||
|---|---|---|---|
| Video Quality | comp- ression | data rate (megs/sec) | storage min/gig |
| Multimedia | 12:1 | 1.5 | 11 |
| Home VHS | 9:1 | 2 | 8 |
| SVHS Prosumer | 6:1 | 3 | 5.5 |
| DV/FireWire | 5:1 | 3.6 | 4.5 |
| Professional SVHS | 4:1 | 4.5 | 3.5 |
| BetaCam | 3:1 | 6 | 2.5 |
This does not mean that you must invest now in super fast storage. Just be prepared that you may have to live with lower video quality until you can get the kind of storage your capture card craves. The good news for digital videographers is that hard drives keep getting faster and cheaper. SCSI prices have fallen dramatically and new EIDE RAID systems are an excellent choice for hi-resolution home digital videography.
A very important issue you need to know about NLE and video storage is the 2GB file limitation in Video for Windows. This means that you can't create an avi file over 2GB in size. Even though new versions of Windows let you create partitions that are 100s of GB in size, the 2GB avi file limit remains. Note: New rendering technology and playback utilities have made it possible to work around this limitation.
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) are not very practical. This combined with the massive storage required, makes us recommend doing NLE in segments of 15 minutes at a time. If you are planning on creating a movie over an hour long, be prepared for the rendering times involved.
You can also check out our interactive video capture card comparison page. We tell you what operating systems each card works on, what non linear editing software is included and list any special features. I want to see the interactive comparison page!
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