Desktop
Video: A Starter's Guide to Video Editing
Introduction
The home video; for years now it has been a staple of North
American households due to the affordability of consumer level camcorders. Home
videos may be attractively priced, but they almost completely lack editing
capability. I’m sure everyone has had to watch a home video that just seemed
to go on forever because it practically did. The traditional analog methods of
video editing are usually beyond the financial reach of the majority of home
users, so the only method available was the archaic VCR to VCR dubbing platform.
Not only is this method difficult and time consuming, it also tends to produce
messy results on consumer level VCRs. Clean cuts, nice transitions and
attractive titles were just not available to the average home user.
Computers eventually started to ease the video editing process, but this was limited by cost to the high-end professional market. The beauty of these expensive editing computers was that you could edit a video just like a document with cutting and pasting. This was called non-linear editing, as opposed to linear editing, in which a video had to be edited in sequence. These new computers were also capable of adding digital effects, smooth transitions and multiple layers of audio.
Finally the trickle-down effect has reached the home computing market. Home computers powerful enough to handle the demands of decent quality video editing! The lower costs of CPUs, RAM, and especially hard drives, have made the dream of good quality video on the home PC a reality.
How
Does it Work?
Why, suddenly after years of it being impossible to edit video at reasonable
cost on home computers, is the technology suddenly now affordable? Some of the
answer has to do with the lowering of computer prices over the past few years,
but mostly it results from new, cost-effective video compression.
Compression
The only way a home computer can effectively deal with the huge amounts of data required for good quality video is to compress it. To give you an idea of the storage needed for non-compressed video data, here are a few interesting numbers: a 9-second uncompressed (no audio) AVI file takes up 261 Megabytes. That’s 29 Megabytes a second. In order to produce a 20-minute video file (with no audio) over 38 gigabytes of storage space would be required. That’s fine for George Lucas, but average computer users cannot afford to buy drives like that by the dozen.
To get around this problem, compression formats were devised to dramatically reduce file size, yet retain acceptable quality. These compressors work by throwing out data unimportant to the overall quality of the image.
Take, for example, a blue sky: when you digitize this image there will most likely be thousands of shades of blue present in the image. The compressor takes those thousands of colours and makes them into one, in this case blue. Compressors will also take the movement data out of portions of the video file in which little or no movement are taking place. The consumer often has the choice of how much to compress, while considering final image quality. Our 38 Gigabyte 20 minute file would only take 2.6 Gigabytes compressed in MJPEG format, high quality mode: quite a difference in size, but not a huge difference in quality when viewed on a TV.
Of course, these compression chips and their software were very expensive to produce until recently; but today’s CPUs are so fast they can help with a lot of the work, reducing overall cost.
Types of Compression
MJPEG:
The industry standard, capable of images up to S-VHS quality.
Indeo: Intel’s software compression
format, most suitable for web based video.
Cinepak: The compression format used
most often in QuickTime files.
DV: The format used by Digital
Camcorders, very similar to MPEG-2.
MPEG: High compression ratio, tops
out at VHS quality.
MPEG-2: Format used by DVD extremely
high quality.
Edit Decision Lists
The other way to edit video with a computer is to do so with edit decision lists. Using this style the computer only digitizes very small, poor quality clips from the video source. Using these poor quality clips the consumer then uses his or her software to decide what edits are to be made and what transitions are to be produced. After the decisions are made the software and the computer control the camera and automatically do the edits. The only part the computer plays in the editing is producing the transitions and controlling the camera. This method of editing is often quicker than digitizing everything and there is no compression. The only downside is that a very high-end video camera and capture device are required with the proper controls and outputs. One of these control formats is called Control L-Lanc and is only found on very expensive camcorders. Many new DV camcorders can be controlled in a similar way but that is a whole article in itself.
Smart Rendering
Something that almost all new video editing devices do in some fashion is Smartrender. This allows portions of the video file to avoid being re-rendered when the final output file is created. Previously, all segments of a video had to be re-rendered when the final file was produced even if no changes (besides simple cuts) had been made. Smartrender can figure out if anything was done to a segment and decide to not re-render the file, saving a lot of time in the final rendering process.
Quality
All new video-editing devices let you decide about the quality of the final project you are attempting to produce. Depending on your destination medium, you can decide what resolution and compression level is best for your project. If you were developing a video for the web you would use a popular compression format with high compression and a low resolution; if your final output was an S-VHS tape or other high quality format, you would use less compression and a higher resolution. The ability to dictate your quality level is an important tool for desktop video producers.
What
Do You Need?
The following segment will address what's needed to start
working with Desktop Video on a PC.
Source
Before you can edit you have to have something to edit. Your source can be any of the following: video camera, VCR, and/or television. Your source just requires a video output of some kind (of course your capture device must have the same style of input).
Video formats are as follows:
DV: Digital format similar to MPEG-2,
almost broadcast quality. About 500 lines of resolution.
HI-8: Analog, good quality. About 400
lines of resolution.
8-MM: Analog, decent quality. About
300 lines of resolution.
VHS: Analog, poor quality. About 250
lines of resolution.
Betacam SP: Analog, professional
quality. 500 Lines of Resolution.
Computer
Get as powerful a system as possible.
Processor: P-II 350 or higher.
Due to the complex mathematical nature of compression codecs, the faster your CPU is the faster your projects will render. I have noticed that Celeron systems are almost as fast as their equivalent P-II or P-III processors while working with video. Most major software editing packages are planning to support the Pentium III's new SSE instructions, so if you can afford a P-III it could be a wise investment.
RAM: 64 Megabytes of RAM or higher.
Video editing is very data-intensive and requires constant data updates. The more RAM, the less your hard drive has to be accessed. This in turn speeds up the responsiveness of your editing software.
Free PCI slot (for the capture device).
Sound Card: 16 bit 44khz PCI sound card or better.
Why PCI? Well, PCI sound cards tend to have lower CPU utilization rates than ISA, which in turn frees up more CPU time for compression and decompression. This lower CPU utilization also tends to create videos with better sound synchronization.
Hard Drive: 8.4 Gigabyte Hard Drive or better (get a 7200 rpm drive or faster if possible).
Video capturing and editing are just plain space hogs, so get the largest drive you can afford. 7200 rpm (or better) drives are recommended because the higher spindle rate translates into better data transfer rates. Because of the immense amounts of data being pushed through your computer while editing, even a slight increase in transfer rates will speed up your work. Buffer size seems to be only important up to 512K; larger buffers do not improve performance dramatically.
Capture Device:
This is how you get the video into the computer, a very important part of the overall video editing system. Most capture devices do pretty much the same thing, but the more expensive ones tend to do it faster. Get as good a device as you can afford and you will save time and effort in the long run. Of course, if you’re only going to be producing video for the Web or a CD-ROM, then you won’t need the extra speed and features of the of the higher end devices.
There are two types of capture devices, analog and Firewire.
Analog capture devices take the analog signal of a camcorder, such as a Hi-8 camera or VHS camera, and digitize its video into a format the computer can handle. These devices tend to compress the video file on the fly, as the computer captures the data.
Firewire capture cards only work with Digital camcorders (DV or Digital 8) with a Firewire (IEE1394, or I-Link) on-camera interface. The Firewire capture card does a straight digital transfer of the camcorder data onto the hard drive. Since the data is already compressed, further compression is not required. Firewire cards and Firewire-capable cameras enable the consumer to create video with no "generation loss" whatsoever, because an exact duplicate of ones and zeros is all that’s being used.
Capture
Cards and Software
Capture Cards
and Prices
Before you buy your capture card, do yourself a favor: do your research. There are countless Web Pages and discussion groups concerning desktop video and there’s a good chance someone out there has been in the same situation as you are. Here are a few cards that offer good value to the consumer:
Low End: (suitable for creating home VHS videos and clips for the Internet)
Pinnacle StudioDC10+ ($199.95): A MJPEG based internal PCI device, which is capable of close to S-VHS quality video. Comes bundled with Pinnacle’s own editing software, which is easy to use but not that powerful. A great card for someone just starting with video editing.
Pinnacle Studio400 ($199.95): An external device that captures a low quality series of files to your hard drive, and which, after you have finished your editing, controls your camcorder (via remote) to complete the process. Final quality is VHS , which is fine for home videos and the Internet. Comes with Pinnacle’s own editing software. Note: Your camera must have a wireless remote control in order for this device to work.
Matrox Marvel ($249.95): This all-in-one AGP card acts as a MJPEG capture device, 3D accelerator, 2D video card, and TV tuner. The video output is VHS to low end S-VHS quality. The card comes bundled with AVID Cinema which is very easy to use but not very flexible. A good choice for the starting video editor with little computer expansion potential.
Higher End: (suitable for better quality home video and low-end professional work)
Pinnacle DC30pro ($749.99): Internal PCI device capable of delivering S-VHS (nearly professional) quality video. Comes bundled with Premiere 5.1 and a host of effects plug-ins. Captures its own audio as opposed to going through your sound card to ensure prefect sound synchronization. Great software and good image quality make this a good card for the higher end home user.
Truevision Bravado 2000 ($499.99): This internal FIREWIRE device lets DV camcorder users edit video without any generation loss. This card comes bundled with the full version of Premiere 5.0. For consumers with a DV camcorder looking to make very high quality videos at a decent price this is the perfect package. The only reason a solution like this is not considered professional is the speed of the final rendering. Professional Firewire devices have a hardware-based compression chip which renders files in real time. This package is exceptional because it cost less than Premiere does when purchased separately and it includes a Firewire capture card.
Of course there are lots of other cards out there, with more being released every day; but the above devices are all considered good products in the industry.
Software
To produce any video with all this raw footage on your hard drive, you must have software which enables the cutting and pasting and easy transitions unique to computer non-linear editing. Most capture cards come with some kind of usable video production software, but for your info, here is a list of the most popular non-linear editing software packages. In the future, I would like to conduct a roundup of a number of popular editing packages available.
Adobe
Premiere 6
Avid Cinema
Avid McXpress
ClipView by FutureTel
In Sync Speed Razor LE
In Sync Speed Razor DV
In Sync Mach Razor
In Sync Mach Razor RT
MGI
VideoWave
Ulead Media Studio Pro
These prices are scary looking, but many capture cards come with a lite version of Premiere or MediaStudio. When it comes to overall flexibility and power among the lower end software packages, Premiere and Media Studio offer the best value for money. Both are very similar to the professional packages but at a much lower price. Programs like Video Wave and AVID Cinema are strictly for beginners.