Video Technology and Signal Types

Study Notes

Video is a technology that captures, records, processes, stores, and transmits a sequence of still images representing scenes in motion.
Animation starts from discrete pictures and then process to create an illusion of continuous motion.

Analog video is recorded as a signal.
It is still used because of existing video clips stored in analog format on video tapes and the availability of equipment for recording and playing analog video.
Disadvantages of analog video include:
- Degradation of video quality after several tape dubbings.
- Video tape is difficult to store and easily damaged by dust and humidity.
- It can be time-consuming to fast-forward or rewind to get to the desired video segment.
- It can be difficult to get the tape to stop at a specific video frame.

Examples of analog formats include:
- VHS: the most common video format.
- S-VHS: better quality than VHS.
- Hi-8: better quality than S-VHS.
- Betacam SP: a high-quality, analog video format used in professional video editing.

Analog video signal is transferred by an analog signal that contains luminance (brightness) and chrominance (color) of the image.
Most TV still sends and receives video as an analog signal.
There are three types of analog video signal:
- Component
- Composite
- S-Video

Signals are split into 2 or more components:
- Luminance (brightness) - Y
- Chroma (colors) - U and V
Advantages:
- Gives the best color reproduction.
- No "crosstalk" between the three different channels.
Disadvantages:
- Requires more bandwidth and good synchronization of the three components.

S-Video = separates into 2 signals:
- Luminance (brightness) - Y
- Chroma (colors) - C
Also known as Separate Video or Y/C.
Video quality is better than composite video, worse than component video.

Refers to video that is already in digital format.
There is little or no degradation in quality when digital video is transferred to the computer.
Digital video is transferred by digital signal.
In most multimedia applications, video signals need to be in digital form to store them in the computer's memory and to easily edit and integrate them with other media types.

Video captured using a DV camera can be transferred to the computer by using:
- USB (Universal Serial Bus)
  - FireWire (also known as IEEE 1394)
USB:
- USB 1.1 has a maximum data rate at 12 Mbps.
- USB 2.0 has a data rate at 480 Mbps.
- USB 3.0 has a data rate up to 4.8 Gbps.
FireWire:
- Has a data rate at 400 Mbps.
- Is well suited to demanding activities such as uploading video to a computer.