Capturing video
‐The type of video, or format, and to a lesser extent the connection type you select to capture content, can dramatically affect the quality of the video on the computer. ‐ It’s always desirable to start with the highest possible quality video and audio signal.
‐The higher the quality of the source material used, the higher the quality of the final compression results.
ÆToday’s editing software, such as Adobe Premiere® Pro, and many compression software tools, can capture content in a variety of ways. Video can be captured from analogue or digital sources. Both have a variety of different video and audio formats available and various physical connection types that can be used.
SIGNAL FORMATS AND CABLES
• Analogue formats:
‐Analog video uses fluctuating voltage and frequency signals to transmit image data.
‐Ranges greatly in quality but is inherently susceptible to visual interference from electronic noise and suffers attenuation, or the loss of signal power and quality over long cable runs (usually 300 meters or more).
‐Equipment that supports analog signals is generally more affordable
Because computers only use digital data, the analog source must be converted to a digital copy to be captured. When it is sent back to an analog medium like videotape, it is converted back to an analog signal. This conversion can lead to minor errors (quantization errors) being introduced.
ÆYou can minimize these quantization errors by using the right format, good equipment, cables, and connections.
• Composite:
‐A composite video signal carries the luminance and the chrominance channels in a single signal.
‐Biggest problem = that luma information can leak into chroma, and vice versa. This leakage can lead to noise, known as chroma crawl, which can be amplified by the video capture process and reduce the overall quality.