Streaming Media

Capturing your video for streaming ... by Russell Shaw

In last month's column, I discussed some tips for you to shoot great outdoor video suitable for encoding into streaming media content for your site.

Regardless of the type of video you have taken, your next step will be to transfer the content from your digital video camera to your computer for editing, and then encoding.

"Video capture is one of the most system-intensive tasks you can demand of a personal computer," notes a file on leading video editing software program Adobe Premiere's site at www.adobe.com/support/techguides/premiere/performance/main.html. "Getting professional results depends on the performance and capacity of all of the components of your system working together to pass frames from the video-capture card to the processor and hard disk. Your system is only as fast as its slowest component."

To ensure the most efficient transfer between your video camera and your PC, you will need to be aware of several rules of thumb. Some of these will require you to have:

• A video-capture card robust enough to capture video at the appropriate frame rate and size for the Internet.
• An IEEE 1394 connector for the actual transfer of the video content from your video camera to your computer.
• An IEEE 1394 port on your PC, to receive the video content as it is being transferred.
• A hard disk with a spin rate fast enough to store captured video frames as soon as they are handed off from the video card.
• A system with enough processor speed to handle the transfer of your video data, as well as with enough memory to handle the video transfer, as well as smoothly conduct the video editing and encoding tasks.
• A hard disk with enough free space to store your "raw" video content prior to its being edited and encoded.

Now, I will present these issues in detail, and review some recommended capabilities:

Understanding Capture Cards

With the appropriate video capture software, the video feed you are attempting to transfer will be recognized and accepted by your PC.

Video capture cards are necessary for this purpose. ViewCast Corp.'s Osprey-210, which costs around $200.00 with a connecting cable included, is one of the most popular. The card itself inserts into an available PCI slot or port, and comes with a set of drivers.

You may not need to go that route, however. Most video-editing software has built-in video capture capabilities that work in tandem with IEEE 1394 FireWire Ports.

If you use Windows XP, the bundled-in Windows Movie Maker application also has built-in video capturing and editing.

Abobe Premiere has some recommendations for smooth video transfer. Predictably, the more frames per second that need to be moved, the higher the necessary transfer rate. Television station newsroom edit bays often aim for the NTSC video standard rate of 29.97 frames per second and an eventual display of 720 by 480 pixels for digital video. Many streaming content creators are satisfied with 15 frames per second and 320x 240 resolution.

The Magic of IEEE 1394

Your digital camera contains an IEEE 1394 connector port. If your PC or notebook computer is three years old or newer, it should as well. You will simply need to obtain a cable to connect both ports.

The cable itself is a piece of cake. Decent 3 to 6-foot IEEE 1394 cables are available at most computer and electrical supply stores. Typically, they cost between $10 and $25.

For older PCs you will need a IEEE 1394 adapter card, which will plug in to one of your PCI (Peripheral Component Interconnect) slots. I don't wish to be a snob, but if your PC is too hold to have a built-in IEEE 1394 connector port, it probably is not robust enough to handle the demands of video transfer, editing, and encoding.

What is IEEE 1394? As you may know, it is a standard for fast transfer of digital data between enabled devices. Historically referred to as "FireWire," IEEE 1394 enables transfer between as many as 63 devices at speeds of 400 megabits per second. IEEE itself stands for the Institute of Electrical and Electronics Engineers, which has blessed the standard.

According to the 1394 Trade Association, "the IEEE 1394 multimedia connection enables simple, low-cost, high-bandwidth isochronous (real-time) data interfacing between computers, peripherals, and consumer electronics products such as camcorders, VCRs, printers, PCs, TVs, and digital cameras. With IEEE 1394-compatible products and systems, users can transfer video or still images from a camera or camcorder to a printer, PC, or television, with no image degradation."

With that understood, all you need to do is connect the camcorder to your PC, make sure that your camcorder is switched on, and then launch your capture software. Most such software has a set of graphical controls that can control your hooked-up camcorder remotely. When I perform transfer tasks, I prefer "batch capture." This lets me transfer all the video content I wish in one fell swoop. After transfer, the video is parked on my hard drive, ready for the editing and encoding tasks ahead.

A Matter Of Spin

You Say You Want 7200 Revolutions? All hard drives spin. This process involves "platters," which store data in sectors for retrieval. With transfer of large digital video files, your hard disk must spin fast enough to store the captured video frames as soon as they arrive from the video card. Once you start editing your stored video, your hard drive must be powerful enough to "seek" and then retrieve the various video content elements quickly.

In terms of the user experience, Internet-delivered streaming video does not have as high an expectation of quality as television. If you envision streaming your content, you will not need to adhere to NTSC video standards. Yet regardless of the medium you intend to deliver your streams in, your hard drive should run at 7200 revolutions per minute or more.

Fortunately, most newer hard drives already have 7200 rpm capabilities. You probably will have more than enough spin power to handle the video transfer.

If your hard disk is not up to the job, two things can happen: both of them, bad. During the transfer stage, frames will not get transferred and will drop out. The result will be discontinuous source video. If "seek" time is too slow, pulling together various sections of a clip during the editing process will be arduous.

Watch Your Processor Speed

Video capture and editing will place major demands on your computer's system. Not only are these processes resource-intensive, but unless you have a workstation or PC specifically devoted to this job, you may well be performing these tasks with other functions running in the background. Many is the time I have been video editing on my system, with Microsoft Word and Outlook Express running in the background.

The best guide to minimum processor speed and other requirements will be the editing and encoding software vendor recommendations on the applicable download page or product box. Adobe Premiere stipulates a minimum 500 megabyte processor speed, but suggests a minimum 800 megabyte rate for real-time preview -- the ability to watch video as you edit it.

The real need for speed comes in the streaming video encoding process Windows Media Encoder 9 stipulates that a dual 2 GHz or higher processor, such as an Intel Xeon or AMD Athlon MP, is best for high-end, video.

Most video editing and encoding products counsel 256 megabytes or more of RAM. Unless you are transferring, editing and encoding on a relic, you should be OK there.

Space Is The Place

Digital video is one big storage hog. You are looking at several factors here. Most video editing programs require several hundred megabytes of storage space. Adobe Premiere 6.5 recommends that you have 600 megabytes free and at the ready.

That's just for starters. Streaming video software such as Windows Media Encoder 9 will cost you about another 10 megabytes of storage just to download it.

Those old MB's will really start adding up once you start storing transferred, raw .avi files on your PC. Ulead Video Studio computes the ratio as high as 13 gigabytes for each hour of digital video transferred and stored at maximum preview quality. My own stored .avi files take up a small fraction of that, but at acceptable minimum you are still looking at several tens of megabytes per minute.

In these days of 140 gigabyte-and-more hard drives, 13 gigs do not sound like a lot. Keep in mind, though, that as you acquire digital video skill, your storage requirements will increase exponentially. That's not even counting all the other stuff on your PC.

Of course you could delete the raw files you have edited and encoded, but I would advise against it. Keeping the source material around in handy, stored form is prudent. You may never know when you need it.

Finally, you will want to ensure that your computer will be able to energetically retrieve your video. Retrieval of large files works best when they are stored in sizable, contiguous blocks on your hard drive. If these blocks are not available, your hard drive will store elements of these files wherever it has room for them. In such cases, you would be looking at the limitations of a fragmented hard disk. If the problem is severe enough, the frame rate at which clips are captured can degrade, and elements can drop out. You already know the answer: run your built-in or added-in defrag utility as often as necessary.