A comparison of two methods of analog-to-digital medical video conversion

The purpose of this study was to compare 2 methods of analog-to-digital video conversion in anticipation of improving, refining, and standardizing digital video production for medical education, diagnosis support, and telemedicine. A video workstation was devised containing 2 analog-to-digital video conversion systems: a digital video media converter with fire wire card and a video capture card. A procedure for final digital video production was created that used equivalent compression, pixel resolution, frame rate, and data rate for both systems. A subjective test was performed in which 12 archived analog videotapes, consisting of magnetic resonance angiograms, ultrasounds, neurosurgeries, and telemedicine applications, were converted digitally using the 2 methods. Randomized side by side video comparisons were analyzed and rated by subjective quality. An objective test was performed by videotaping a gray-scale test pattern off a computer monitor, digitally converting it by the 2 methods, and comparing the gray-scale values to the original pattern. There was no significant difference in overall video quality (P = .31) or grayscale reproduction using the 2 methods of analog-to-digital conversion. When performing simple analog-to-digital video conversion, a video capture card is equal in quality and costs less than a digital video (DV) media converter or fire wire card. If a digital video camera is available for use, then a DV media converter or fire wire card is more advantageous because it enables full operation of the digital video camera.