Your video may have a certain number of frames per second—which could be described as the refresh rate of your video—but screens have a refresh rate too. This video explains the difference, and shares the origin of the word we use to describe things that happen per second: hertz. Once you understand this concept, you'll be better informed and ready to film computer screens, or work with fluorescent lighting.
- [Instructor] There are three factors that can affect…the display of the refresh rate for video on a monitor,…or for that matter, on a projector:…the frames per second of the video,…the refresh rate of the screen,…and the refresh rate of the lamp in the screen.…Let's start backwards.…The refresh rate of the lamp is usually much higher…than the refresh rate of the screen.…Let's say typically 200 Hertz, that's 200 times per second.…By the way, I love explaining what Hertz means.…There was a time when we didn't have a word…for things that happened repeatedly every second,…or times per second.…
A German fellow called Heinrich Rudolph Hertz…proved the Theory of Electromagnetic Waves…in the late 19th century,…and cycles per second were named in his honor.…So Hertz just means times per second, or cycles per second.…If the lamp in a TV or projector runs at 200 Hertz,…it's easily faster than the refresh rate of the screen.…Screen refresh rates are usually set…as the same as the video standard display.…So that's 60 Hertz for NTSC, and 50 Hertz for PAL.…
Get ready to remove the mystery behind terms you've encountered. If you work in a creative profession, this can enhance your command of the tools you use. Learn what a pixel really is, what color channels are, and what audio frequency is. Discover how color channels, bit depth, and video frame rates work. Find out the difference between codecs and file formats, and how compression is involved. By the end of this course, you'll know how to answer common client questions—like, whether a logo should be supplied in vector or bitmap form, and more.
Note: Motion graphics in this course were provided by Chelsea Parrish: chelseaparrish.com.
- What is a pixel?
- Aspect ratios
- Bit depth
- Alpha and transparency
- Light and color channels
- Color modes: RGB, YUV, CMYK
- Camera depth of field
- Chroma Key and Luma Key
- Blend modes
- Color wheels, vectorscopes, and waveforms
- Video compression and codecs
- Frame rates and timecode
- File formats
- Audio amplitude
- Capturing audio tone as frequency
- Audio timing using the phase
Skill Level Beginner
Learning Video Production and Editingwith Rob Garrott19m 25s Beginner
Video Foundations: Cameras and Shootingwith Anthony Q. Artis2h 58m Appropriate for all
Introduction to Video Dialogue Editingwith Ashley Kennedy3h 14m Appropriate for all
1. How Do Computers Think?
2. How Cameras and Computers Think about Color
3. The Language of Color
4. The Shape of Your Picture and the Speed of Your Video
5. Storing Everything (Codecs)
6. Color Wheels, Vectorscopes, and Waveforms
Understanding waveforms2m 39s
7. Making Changes
8. Audio Made Simple
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