Lesson Review

1.	How are video images structured?
2.	In analog composite video, what are luma and chroma and how are they carried?
3.	How do Y/C video and component video handle luma and chroma signals differently?
4.	What makes compression useful?
5.	Give the pros and cons of lossy codecs.
6.	Name two wrappers that can carry digital video.
7.	How is audio for video usually carried?
8.	What is the function of timecode?
9.	What does drop-frame timecode do?

Answers

1.	As a series of individual frames, which can be further subdivided into two fields.
2.	Luma (brightness) information is represented as a voltage level. Chroma (color) is conveyed by a modulated subcarrier.
3.	Y/C video separates the luma and chroma signals; component video carries the chroma as two separate color-difference signals.
4.	Compression reduces the size of video data by exploiting aspects of the human eye and redundancies in the video information.
5.	Lossy codecs provide more compression, but with reductions in image fidelity.
6.	QuickTime and AVI.
7.	It is carried in a variety of sample rates, bit depths, and track counts. Most professional audio is 48 kHz at 16 bits or greater.
8.	It identifies each video frame with a unique number, allowing frame-accurate operations.
9.	It drops certain timecode numbers to keep timecode time in sync with clock time in NTSC video.