Audio/Video Glossary

When any signal is passed through an electronic circuit, the signal may be changed in many ways.

In audio, odd harmonics (third, fifth, etc.) produce harsh and unpleasant sounding audio.
In video, the image may become blurred, noisy or contain shadows.

Four bytes recorded at the beginning of each sector which tell the address of the sector (expressed as a Logical Block Number) and the mode in which the sector is recorded.

HDTV (High Definition Television)

A television format for producing high resolution video. Typically, these systems provide about 1125 lines of horizontal resolution (compared to 525 for NTSC and 625 for PAL) and an aspect ratio of 16:9, for image quality approaching 35mm film photography.

HELICAL SCAN

A method of recording video information diagonally on a tape, used in home and professional VCRs. High speed rotating video heads scan these diagonal video tracks, giving an effective tape speed much higher than the actual tape speed allowing more information to be recorded on a given length of magnetic tape.

HFS (Hierarchical File System)

Used by the Macintosh computer platform. HFS formatted CD-ROMs have the same file structure as an Apple hard disk.

HI-8

An improved version of the 8mm tape format capable of recording better picture resolution (definition). A higher-density tape is required which provides a wider luminance bandwidth, resulting in sharper picture quality (over 400 horizontal lines vs. 240 for standard 8mm) and improved signal-to-noise ratio. Camcorders using this format are very small, light and provide a picture quality equivalent to S-VHS.

HI-FI (High Fidelity)

Most commonly used to refer to the high quality AFM audio tracks recorded by many VCRs. These tracks provide audio quality approaching that of a CD. However, because they are combined with the video signal before recording, audio dubs using them are impossible without re-recording the video.

HIGH SIERRA FORMAT

The standard logical format for CD-ROM originally proposed by the High Sierra Group, on which the ISO 9660 standard is based; essentially identical to ISO 9660. The original High Sierra format is rarely used any longer.

HISS

The most common audible noise component in audio recording, stemming from a combination of circuit and tape noise. Several noise reduction systems are available, such as Dolby, DBX, DNR (Dynamic Noise Reduction), DNL (Dynamic Noise Limiter), to help alleviate such problems.

HORIZONTAL RESOLUTION

Rating of the fine detail (definition) of a TV picture, measured in scan lines. The more lines, the higher the resolution and the better the picture. A standard VHS format VCR produces 240 lines of horizontal resolution, while over 400 lines are possible with S-VHS and Hi-8 camcorders.

HORIZONTAL SYNC

The sync pulse signal produced at the beginning of each video scan line which keeps a video monitor’s horizontal scan rate in step with the transmission of each new line. (See BLANKING LEVEL)

HUE

Often used synonymously with the term tint. It is the dominant wavelength which distinguishes a color such as red, yellow, etc. Most commonly, video hue is influenced by:

A camera’s white balance
Scene lighting

HYBRID DISC

Recordable disc on which one or more sessions are already recorded, but the disc is not closed, leaving space open for future recording. However, in popular use, the term "hybrid" often refers to a disc containing both Macintosh and DOS/Windows software platforms. The disc contains separate ISO 9660 and HFS partitions.

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