System information
Analog
When discussing audio, this term refers to a method of reproducing a sound wave with voltage fluctuations
that are analogous to the pressure fluctuations of the sound wave. This is different from digital recording in
that these fluctuations are infinitely varying rather than discrete changes at sample time. See
"Quantization" on page 645.
Aspect Ratio
Describes the frame size of your video as a ratio of its width to its height. For example, video shot in NTSC
DV format has a frame size of 720 by 480 pixels, which is roughly a 1.33:1 aspect ratio:
720 (frame width) ÷ 480 (frame height) = 1.5
1.5 x 0.9091 (pixel aspect ratio) = 1.36365.
Frame Size Example
4:3 Standard Television
1.33:1 Aspect Ratio
16x9 Widescreen Television
1.78:1 Aspect Ratio
Academy Flat Theatrical Frame
1.85:1
Academy Scope Theatrical Frame
2.35:1 Aspect Ratio
Attack
The attack of a sound is the initial portion of the sound. Percussive sounds (drums, piano, guitar plucks) are
said to have a fast attack. This means that the sound reaches its maximum amplitude in a very short time.
Sounds that slowly swell up in volume (soft strings and wind sounds) are said to have a slow attack.
632CHAPTER 34