Understanding Audio

on Sunday, June 29, 2008

Consider how audio affects the feel of a video program. Honking car horns on a busy street; crashing surf and calling seagulls at a beach; a howling wolf on the moors — these sounds help us identify a place as quickly as our eyes can, if not quicker. If a picture is worth a thousand words, sometimes a sound in your movie is worth a thousand pictures.
What is audio? Well, if I check my notes from high-school science class, I get the impression that audio is produced by sound waves moving through the air. Human beings hear those sound waves such as condolence phrases being told, they make our eardrums vibrate. The speed at which a sound makes the eardrum vibrate is the frequency. Frequency is measured in kilohertz (kHz), and one kHz equals one thousand vibrations per second. (You could say it really hertz when your eardrums vibrate . . . get it?) A lower-frequency sound is perceived as a lower pitch or tone, and a higher-frequency sound is perceived as a high pitch or tone. The volume or intensity of audio is measured in decibels (dB).

Capturing your video


Once all your settings are, uh, set, you’re ready to start capturing. (Finally!) I recommend that you rewind the tape in your VCR or camcorder to at least 15 seconds before the point at which you want to begin capturing. Then follow these steps:
  1. Click the Start Capture button at the bottom of the Studio capture window. The Capture Video dialog box appears.
  2. Enter a descriptive name for the capture.
  3. If you want to automatically stop capturing after a certain period of time, enter the maximum number of minutes and seconds for the capture.
  4. Press Play on the VCR or camcorder.
  5. Click Start Capture within the Capture Video dialog box. The capture process begins, and you’ll notice that the green Start Capture button changes to the red Stop Capture button. As Studio captures your video, keep an eye on the Frames Dropped field under the preview window. If any frames are dropped, try to determine the cause and then recapture the video. Common causes of dropped frames include programs running in the background, power saver modes, or a hard disk that hasn’t been defragmented recently.
  6. Click Stop Capture when you’re done capturing.
Studio reviews the video that has been captured and improves scene detection if possible. When the process is done, the captured clips appear in Studio’s clip album.

Adjusting video-capture settings in Studio


To make sure Studio is ready to capture analog video instead of digital video, click the Settings button at the bottom of the capture window. The Pinnacle Studio Setup Options dialog box appears. Click the Capture Source tab to bring it to the front. On that tab, review the following settings:
  • Video: Choose your analog capture source in this menu. The choices in the menu will vary depending upon what hardware you have installed.
  • Audio: This menu should match the Video menu.
  • Use Overlay and Capture Preview: I recommend that you leave both these options disabled. Leaving these options on may cause dropped frames (that is, some video frames are missed during the capture) on some computers.
  • Scene detection during video capture: This setting determines when a new scene is created. For most purposes, I recommend choosing “Automatic based on video content” for analog capture.
  • Data rate: This section tells you how fast your hard disk can read or write. Click the Test Data Rate button to get a current speed estimate. Ideally, both numbers should be higher than 10,000 kilobytes per second for analog capture. If your system can’t reach that speed.
If you have trouble with dropped frames when you capture analog video, try disabling automatic scene detection by choosing the No Automatic Scene Detection option. Scene detection uses some computer resources, and it can cause some dropped frames if your computer isn’t quite fast enough. When you’re done reviewing settings on the Capture Source tab, click OK to close the Setup Options dialog box. You are almost ready to begin capturing analog video. Like many analog video capture programs, Studio lets you finetune the audio and video that will be captured. Click the buttons on either side of the capture controller to open the Video Input and Audio Capture control. These control panels allow you to adjust color, brightness, and audio levels of the incoming video. On the Video Input control panel, first choose whether you’re going to capture video from the Composite or S-Video connectors using the radio buttons under Video Input. The Audio Capture control panel allows you to turn audio capture on or off.
Now press Play on your VCR or camcorder to begin playing the video you plan to capture, but don’t start capturing it yet. As you play the analog video, watch the picture in the preview screen in the upper right corner of the Studio program window. If you don’t like the picture quality, you can use the brightness, contrast, sharpness, hue, and color saturation sliders on the Video Input control panel to adjust the picture. Experiment a bit with the settings to achieve the best result.
As you play your analog tape, you’ll probably notice that although you can see the video picture in the preview window, you can’t hear the sound through your computer’s speakers. That’s okay. Keep an eye on the audio meters on the Audio Capture control panel. They should move up and down as the movie plays. Ideally, most audio will be in the high green or low yellow portion of the audio meters. Adjust the audio-level slider between the meters if the levels seem too high or too low. If the audio seems biased too much to the left or right, adjust the balance slider at the bottom of the control panel. If you’re lucky, the tape you’re going to capture from has color bars and a tone at the beginning or end. In that case, use the bars and tone to calibrate your video picture and sound. The tone is really handy because it’s a standard 1KHz (kilohertz) tone designed specifically for calibrating audio levels. Adjust the audio-level slider so both meters read just at the bottom of the yellow. When you’re done playing with the settings in the Video and Audio control panels, stop the tape in your VCR or camcorder and rewind it back to where you want to begin capturing.

Using a video converter


Video converters are kind of neat because they don’t require you to break out the tools and open up your computer case. As their name implies, video converters convert analog video of your visit in Aztec ruins to digital before it even gets inside your computer.
The converter has connectors for your analog VCR or camcorder, and it connects to your computer via the FireWire port. Converters are available at many electronics retailers for about $200. Common video converters include
  • Canopus ADVC-50: www.canopuscorp.com
  • Data Video DAC-100: www.datavideo-tek.com
  • Dazzle Hollywood DV Bridge: www.dazzle.com
All three of these video converters are compatible with both Macintosh and Windows computers. Video converters pipe in video using a FireWire port —so as far as your computer is concerned, you’re capturing digital video. Capturing analog video using a video converter is just like capturing digital video. The only difference is that you’ll have to manually press Play on your analog camcorder or VCR before you start to capture.
If you have a digital camcorder, you might be able to use it as a video converter for analog video. Digital camcorders have analog connectors so you can hook them up to a regular VCR. Hook up a VCR to the camcorder, set up the camcorder and your computer for digital capture, and push play on the VCR. If the video picture from the VCR appears on the capture-preview screen on your computer, you can use this setup to capture analog video. This should work without having to first record the video onto tape in your digital camcorder, which means that using your camcorder as a converter won’t cause increased wear on the camcorder. Alas, some camcorders won’t allow analog input while a FireWire cable is plugged in. You’ll have to experiment with your own camera to find out if this method will work.

How to use capture card


The best quality in analog video capture is available if you use a special video-capture card. Analog-capture cards are available at many computer and electronics retailers. A capture card actually connects to the motherboard inside your computer — so installation will require some expertise in working with computer hardware. Also, make sure that your computer actually has room to add an expansion card. I briefly discuss how to identify empty expansion slots and install a FireWire card in a Windows PC. Installing an analog capture card is very similar. If you buy a capture card, make sure it can capture analog video. Many FireWire cards are marketed as digital-video capture cards, but if you don’t read the packaging carefully, you might be confused about the card’s capabilities. If a FireWire card doesn’t specifically say that it can also capture analog video, assume that it can’t.

I use a capture card made by Pinnacle Systems (www.pinnaclesys.com) called the Pinnacle AVDV Capture Card. This card has FireWire ports for capturing digital video, as well as an external breakout box with analog connectors for capturing analog video. Most analog capture cards have breakout boxes because there usually isn’t enough room on the back of a narrow comes the Pinnacle Studio Deluxe package, which retails for $300. If your PC already has a FireWire port, look into Pinnacle Studio AV ($130), which comes with an analog-capture card.

If you decide to buy and install an analog-capture card in your computer, I strongly recommend that you use the software that came with the card when you’re ready to capture. A capture card normally comes with software that is optimized for that card.
After you have a capture card installed in your computer, all you need to do is connect your VCR or analog camcorder to the appropriate ports. Usually those ports are located on an external breakout box because there probably isn’t room on the back of the actual card. You will probably have to choose from among several different kinds of connectors:
  • Composite: Composite connectors — the most common type — are often used to connect video components in a home entertainment system. Composite connectors are also sometimes called RCA jacks and use only one connector for the video signal. A composite video connector is usually color-coded yellow. Red and white composite connectors are for audio. Make sure you connect all three.
  • S-Video: S-video connectors are found on many higher-quality analog camcorders as well as S-VHS VCRs. S-Video provides a higher-quality picture, so use it if it’s available as an option. The S-Video connector only carries video, so you’ll still need to use the red and white audio connectors for sound.
  • Component: Component video connectors often look like composite connectors, but the video image is broken up over three separate connectors color-coded red, green, and blue. The red cable is sometimes also labeled R-Y and carries the red portion of the video image, minus brightness information.
The green cable — sometimes labeled Y —carries brightness information. Video geeks like to say luminance instead of brightness, but it means the same thing. The blue wire — sometimes labeled B-Y — carried the blue portion of the image, minus brightness. Component video provides a higher quality video image, but it’s usually only found on the most expensive, professional-grade video capture cards. Like S-Video, component connectors don’t carry audio, so you’ll still need to hook up the red and white audio cables. When you’re done hooking everything up, you’ll probably have quite a rat’s nest of cables going everywhere. Your capture software won’t be able to control your VCR or camcorder through the analog cables, so you’ll have to manually press Play on the device before you can start capturing in the software.

Preparing your computer for analog video

on Thursday, June 19, 2008

Getting your computer ready to capture analog video is a lot like getting ready to capture digital video. Before you can capture analog video, you have to
  • Set up your capture hardware. I’ll show you what hardware you need and how to set it up in the following section, “Setting up capture hardware.”
  • Turn off unnecessary programs. Whether you’re working with analog or digital video, your computer will work more efficiently if you close all programs that are not needed for the actual capture process.
  • Make sure there’s enough free space on your hard disk. Five minutes of digital video uses about 1GB (gigabyte) of hard-disk space. Unfortunately, there is no single, simple formula for figuring out how much space your analog video will require.
Digital video recorded with a MiniDV, MicroMV, or Digital8 camcorder uses the DV codec, which uses a steady 200MB (megabytes) per minute of video. A codec — short for compressor/decompressor — is the software scheme used to compress video so it fits reasonably on your computer. Some analog-capture devices let you choose from a list of different codecs to use during video capture; many codecs have settings you can adjust. Which codec you use (and the settings you select) can greatly affect both the quality of your capture video and the amount of space it uses up on your hard disk. Fortunately, most analog video-capture programs make it pretty easy to determine whether you have enough hard disk space. The Pinnacle Studio capture window, for, shows you exactly how much free space is available on your hard disk, and it gives you an estimate of how much video you can capture using the current settings.

What to do if capture stops unexpectedly?


If the capture process stops before you want it to, your culprit could be mechanical. Check the following:
  • Did you forget to rewind the camcorder tape? This is a classic “oops” that happens to nearly everybody sooner or later.
  • Is your hard disk full? This is bad juju, by the way. Try to avoid filling up your hard disk at all costs. Buy a DVD-RW drive to backup regularly.
  • Is there a timecode break on the tape? Inconsistent timecode on a digital videotape can create all sorts of havoc when software tries to capture video.
  • Did Fluffy or Junior step on the Esc key? It happens. My cat has fouled more than one capture process. (Hey, biomechanical still counts as “mechanical,” right?)

What to do if frames drop out during capture


Video usually has about 30 frames per second, but if the capture process doesn’t go smoothly, some of those frames could get missed or dropped, as video pros call it. Dropped frames show up as jerky video and cause all kinds of other editing problems, and usually point an accusing finger at your hardware, for one of four possible reasons:
  • Your computer isn’t fast enough: Does your computer meet the system requirements that I recommend in Chapter 2? How fast is the processor? Does it have enough RAM?
  • Your computer isn’t operating efficiently: Make sure all unnecessary programs are closed as I described earlier in this chapter. You may also be able to tweak your computer’s settings for better video-capture performance. Check out the OS Tweaks in the Tech Support section of www.videoguys.com for tips and tricks for helping your computer make the best possible use of its resources.
  • You left programs running: Make sure that your e-mail program, Internet browser, music jukebox, and other programs are closed. I also recommend that you disable your Internet connection during video capture, even if you have a broadband (cable modem, DSL) connection. When your connection is active, you probably have a few utilities running in the background looking for software updates to your operating system and other programs. A well-meaning message that updates are available for download might appear right in the middle of video capture, causing dropped frames.
  • Your hard disk can’t handle the data rate: First off, does your hard disk meet the requirements? If so, maybe some harddisk maintenance is in order. First of all, the more stuff that is packed onto your hard disk, the slower it will be. This is one reason I recommend (pretty often, in fact) that you multiply the amount of space you think you’ll need by four. To keep your hard disk working efficiently and quickly, defragment your hard disk periodically (at least once a month). In Windows, choose Start➪All Programs➪Accessories➪System Tools➪Disk Defragmenter. On a Mac, you’ll need to obtain a third-party disk-maintenance tool such as Norton Disk Doctor.
  • If you’re using Pinnacle Studio, you can use that software to test your hard disk’s data rate. In Studio, choose Setup➪Capture Source. In the Setup Options dialog box that appears, click the Test Data Rate button. Studio tests your data rate and lists the read, write, and Max safe speeds. The Max safe speed is a speed which Studio determines is necessary for glitch-free video capture. For DV-format video, the Max safe speed should be at least 4000KB per second.

What to do if you can’t control your camera through your capture software


When you click Play or Rewind on the camera controls in your video-capture software, your digital camcorder should respond. If not, check the following items:
  • Check all the obvious things first: Are the cables connected properly? Is your camcorder turned on to VTR mode? Does the camera have a dead battery?
  • Did the camera automatically power down due to inactivity? If so, check the camera’s documentation to see if you can temporarily disable the power saver mode. Also, consider plugging the camera in to a charger or AC power adaptor so that you aren’t just running on battery juice.
  • Is your FireWire card installed correctly? Open the System icon in the Performance and Maintenance section of the Windows Control Panel. Click the Hardware tab, and then click the Device Manager button. If you see a yellow exclamation mark under IEEE 1394 Bus host controllers, you have a hardware problem.
  • Is your camcorder supported? Most modern digital camcorders are supported by Apple iMovie, Pinnacle Studio, Windows Movie Maker, and other programs. But if the software just doesn’t seem to recognize the camera, check the software vendor’s Web site (www.apple.com, www.pinnaclesys.com, or www.microsoft.com, respectively) for camera compatibility information. If your camera is so new that it wasn’t originally supported by your editing software, check the publisher’s Web site to see if software updates are available to accommodate newer camcorder models.

Capturing video in Apple iMovie


Apple’s iMovie doesn’t offer quite as many capture options as Pinnacle Studio, but the capture process is simple and effective nonetheless. In fact, you can set just two capture options. To adjust capture preferences, choose iMovie➪Preferences. The Preferences dialog box appears. The two options relating to video capture are as follows:
  • New Clips Go To: This default setting sends incoming clips to the Clips Pane. This is the best place to send new clips unless you want to quickly convert your imported video into a movie without any editing. What’s the fun in that?
  • Automatically Start New Clip at Scene Break: iMovie automatically recognizes when one scene ends and a new one begins. This useful feature often makes editing easier, so I recommend that you leave this option checked.
The iMovie interface is simple and easy to use. To capture video, follow these steps:
  1. Connect your camcorder to the FireWire port as described earlier in this chapter.
  2. Switch the camera to VTR mode.
  3. In iMovie, click the Camera button to switch iMovie to the Camera mode. The Preview pane displays the message Camera Connected (as shown in Figure 5-11).
  4. Use the camera controls to identify a portion of video that you want to capture. When you are ready, rewind the tape about ten seconds before the point at which you want to start capturing.
  5. Click the Play button in the camera controls.
  6. Click the Import button when you want to start importing.
  7. Click the Import button again when you want to stop importing.
It’s just that simple. Your captured clips automatically appear in the Clips Pane, where you can then use them in your movie projects.

how to Capture video in Pinnacle Studio


When you’ve finally got your capture settings just the way you want them, you’re ready to capture. To do so, simply follow these steps:
  1. Connect your camcorder to your FireWire port as described in the previous section.
  2. In Pinnacle Studio, click the Capture tab near the top of the window, or choose View➪Capture.
  3. Configure your capture options
  4. Use the camera controls to shuttle the camcorder tape to the beginning of the spot where you want to start capturing video. Shuttle is another fancy term that video pros like to use when they talk about moving a videotape. When you rewind or fast forward a tape, you are shuttling it. See: You’re already a video pro and you didn’t even know it!
  5. Click the Start Capture button. The Capture Video dialog box appears.
  6. Enter a name for the capture; this name will be used as the filename for the captured video later. If you want, enter a time limit for the capture. By default, the time shown reflects the amount of free space on your hard diskYou can see that my hard disk has enough room to store 607 minutes and 21 seconds of video using my current quality settings. It’s usually safe to just leave this number alone unless you want Pinnacle to automatically stop capturing after a certain amount of time. For example, if I know that I only want to capture the first five minutes, I can enter 5 in the minutes field and 0 in the seconds field. Then I can go and get a cup of coffee or do something else without having to hurry back to manually stop capturing at some point. Pinnacle will automatically stop capturing after five minutes have gone by.
  7. Click Start Capture. Studio automatically starts playing your camcorder and capturing video.
  8. When you want to stop capturing, click the Stop Capture button or press Esc on your keyboard. As Studio captures your video, keep an eye on the Preview window, even if you have disabled on-screen preview in the capture settings. The Frames Dropped field should remain at zero. Dropped frames are a serious quality problem, but they can often be resolved.