Odisha CHSE +2 Vocational Audio Video Technique key terms

The number of complete cycles of a sound wave that pass a fixed point in one second, measured in hertz (Hz); it determines whether a listener perceives a sound as low or high pitch.

The maximum extent to which a sound wave or electrical audio signal deviates from its resting level; larger amplitude means a louder sound or a stronger signal.

The perceptual quality of a sound that lets a listener order it from low to high; it corresponds mainly to frequency, though loudness and waveform also influence it.

The quality that distinguishes two sounds with the same pitch and loudness, such as a violin and a flute; it depends on the mixture of harmonics and how the sound changes over time.

A logarithmic unit used to compare two levels, such as sound pressure or electrical signal strength; audio work uses it because human hearing responds to intensity over a very wide range.

A measure of how strongly a sound wave pushes on a surface, expressed in decibels relative to a standard reference pressure; it is the usual way of stating how loud a sound is in air.

The persistence of sound in an enclosed space after the source stops, caused by repeated reflections from walls, floor and ceiling; it colours recordings and can make speech harder to understand.

The difference between the quietest and loudest levels a system, recording medium or performance can handle without unacceptable noise or distortion, usually expressed in decibels.

The ratio between the level of the wanted audio signal and the level of unwanted background noise in a recording or system, expressed in decibels; a higher figure means cleaner sound.

A diagram or description of how sensitive a microphone is to sound arriving from different directions; common shapes include omnidirectional, cardioid and figure-of-eight.

A directional microphone polar pattern that is most sensitive to sound arriving from the front and rejects much of the sound from the rear; widely used for vocals and speech to reduce spill.

A microphone that converts sound into an electrical signal by means of a charged capacitor whose spacing varies with the sound; it is sensitive, detailed and usually needs phantom power.

A direct-current supply, commonly 48 volts, sent along the same microphone cable that carries the audio signal; it powers condenser microphones and active direct boxes without an extra cable.

A device that accepts several audio inputs and lets an operator set their levels, tone and position, then combines them into one or more output channels for recording, broadcast or amplification.

Deliberate adjustment of the balance between frequency bands in an audio signal, used to reduce rumble, cut harshness, separate instruments or shape the overall tone of a mix.

The number of individual still images, or frames, recorded or displayed per second in video; it affects motion smoothness, file size and compatibility with broadcast standards.

The proportional relationship between the width and height of an image or screen, written as two numbers such as 16:9 or 4:3.

The amount of detail an image or video frame can hold, usually stated as pixel dimensions such as 1920 by 1080 or as a standard label like HD or 4K.

A colour television standard used in India and much of Europe that runs at 625 lines and 25 frames per second; it defines how colour and synchronisation signals are encoded for broadcast.

The brightness component of a video signal, representing how light or dark each part of the picture is; colour television separates it from chrominance so black-and-white receivers can still show an image.

The colour component of a video signal, carrying hue and saturation information separately from brightness; separating it allows compatible colour broadcasting and more efficient compression.

The length of time the camera sensor or film is exposed to light for each frame; in video it influences motion blur and exposure and is often set near twice the frame interval.

The adjustable opening in a lens that controls how much light reaches the sensor; it is stated as an f-number, and smaller f-numbers give a wider opening and shallower depth of field.

The range of distances in front of the camera within which objects appear acceptably sharp; it grows with smaller apertures, shorter focal lengths and greater subject distance.

The camera adjustment that makes a white object record as neutral white under the current lighting, removing unwanted colour casts caused by daylight, tungsten or fluorescent sources.

A composition guideline that divides the frame into a three-by-three grid and places important subjects or horizon lines near the grid lines or intersections for a more balanced image.

A standard studio setup using a key light, a fill light and a back light to model a subject, control contrast and separate the subject from the background.

The main light in a scene, placed to reveal the subject's shape and texture and to establish the direction of shadows; other lights are balanced around it.

A series of simple sketches arranged in shot order that shows framing, action and camera movement for each scene, helping a production team plan and communicate before shooting.

A written checklist, prepared during pre-production, that records each shot to be captured, with its description, location, camera setup and any special requirements.

The consistency of details such as costumes, props, lighting and screen direction from one shot or scene to the next, so that edits do not confuse the audience.

A video editing method in which clips are stored digitally and can be trimmed, reordered and combined in any order without affecting the original footage.

A standard way of labelling each frame of video with hours, minutes, seconds and frame numbers, allowing editors and crews to reference exact moments precisely.

The quiet background sound of a location recorded without dialogue or action; editors use it to fill gaps between takes so that the soundtrack sounds continuous.

Narration spoken by a person who is not seen on screen, recorded separately and placed over pictures to explain, comment on or link the visuals.

A method, implemented in software or hardware, for compressing and decompressing audio or video data; the choice of codec affects file size, quality and playback compatibility.

The amount of data used to store or transmit one second of audio or video, usually expressed in kilobits or megabits per second; higher bit rates generally preserve more quality.