Once shot, video must be digitized by the computer. Many different makes of video capture cards do the job, but look for the highest frame capture rate (30fps, if possible) and compatibility with MicrosoftΓÇÖs Video for Windows format.
A capture card not only digitizes the video information, it also compresses your footage, typically in the Motion-JPEG format. Compression is an absolute necessity, because digitized video generates a godawful lot of data: One second of uncompressed, full-screen video consumes 27MB, and neither your hard disk nor your data bus can continuously stream 27MB/sec. Digitizing is time consuming (longer than real-time playback), so the time to review your raw footage and decide what youΓÇÖll use is before digitizing.
One decision youΓÇÖll want to make early on regards capture quality. The limitations on the speed and compression capability of your card, and the speed of your hard drive, CPU and data bus, will play a factor in this choice. And if you plan on sharing your presentation, youΓÇÖll need to consider the specs of other machines it may run on and accommodate their limitations by further compromising quality. Your final deliverable may only play at 15fps or less. So, while full-screen video is usually 640x480, your footage may have to be quarter screen (320x240). Other performance/quality trade-offs are color depth and whether you capture two video fields per frame or just one. In any case, experiment with all these variables to determine which trade-offs youΓÇÖre willing to make. In general, itΓÇÖs best to capture at the frame size youΓÇÖll wind up using and at the highest frame rate possible.
