Institute for Telecommunication Sciences / Research / Quality of Experience / Video Quality Research / Guides and Tutorials / Video Resources / Tools for Video Quality in Public Safety / Guide to Defining Video Quality Requirements / Video System Functions / Video Processing
VQiPS Processing
Description
Processing refers to any compression, enhancement, restoration, or other operation that is performed on a video signal. This could also refer to any processing done automatically as part of a system, such as the processing done inside a digital camera from RAW to TIFF or JPEG.
Equipment: CODEC
The CODEC performs compression or coding by reducing the amount of space that a video file occupies on its media. Most methods for compression result in a loss of fidelity that is not recoverable. Compression is also used to reduce the amount of bandwidth needed to transmit the video.
If a video has been compressed (or encoded), a decoder must be used to view the video. There are many open-source video encoders/decoders, but there are also many proprietary systems. If a proprietary system is used, and a decoder (player) is not provided, the video cannot be viewed. Features:
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Type of encoding used — as in, H.264, MPEG-2, M-JPEG.
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Output bitrate — how much compression is done.
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Delay — if video is being used for real-time decisions, the encoding and decoding processing can delay the delivery of the video to the decision maker.
Equipment: Analog to Digital Converter
Performs digitization, which is the conversion of an analog video source to a digital format by sampling the analog signal. Features:
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Sampling rate — how many horizontal and vertical samples per frame.
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Bits/sample — how many bits are used for each sample.
Equipment: Editing Software
Performs enhancement for analysis. There are many methods available to increase clarity to certain parts of the video. Examples are frame averaging, edge enhancement, and color balancing. Features:
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Proprietary
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Irreversible data loss
