Unit 3 - Audio and Video Processing

Question 1

What is a Sound Wave?

Answer 1

• Energy propagating through a medium
• Energy is nothing but vibrations of the particles in the medium
• A sound wave creates compressions and rarefactions in the medium

Question 2

Characteristics of Sound Wave:

Answer 2

1. Frequency
2. Wavelength
3. Amplitude
4. Speed

Question 3

Applications of audio in computer:

Answer 3

1. Entertainment & multimedia
2. Communication
3. Education
4. Music production
5. Security

Question 4

Digital Audio file formats:

Answer 4

1. MP3 (MPEG Audio Layer III)
2. WAV (Waveform Audio file format)
3. FLAC (Free Lossless Audio Codec)
4. AIFF (Audio Interchange File Format)
5. VOC (Creative Voice File)

Question 5

What is MP3?

Answer 5

• Lossy compression
• storing and transmitting audio like music
• Comparatively smaller audio size
• File size and audio quality are balanced

Question 6

What is WAV?

Answer 6

• Uncompressed
• Hence it retains original audio data
• File size is large as no compression technique used

Question 7

What is FLAC?

Answer 7

• Lossless compression
• as ‘Free’ -> an open source audio file format
• file size reduced without losing audio quality
• used for digital music distribution

Question 8

What is AIFF?

Answer 8

• Uncompressed and developed by Apple
• used to store high quality sound generally on PC
• File size larger as no compression
• for professional audio applications

Question 9

What is VOC?

Answer 9

• supports the use of compression technique like ADPCM
• used for speech and sound effects
• ADPCM compresses to reduce file size while maintaining audio quality
• used to store mono as well as stereo sound types

Question 10

What is Audio compression?

Answer 10

• Process of reducing the size of the audio file by removing or reducing the redundant or irrelevant data
• Goal is to reduce the file size while maintaining the quality

Question 11

Audio compression techniques:

Answer 11

1. Delta modulation(DM)
2. Adaptive Differential PCM (ADPCM)
3. MPEG (Motion Picture Expert Group)

Question 12

What is video signal?

Answer 12

• an electronic signal that holds the video information like the images and motion, to be displayed on the screen.
• transmitted by video cameras, recorders and computer graphics devices
• via wires or wireless transmission.

Question 13

What are the video signal formats?

Answer 13

1. Component Video
2. Composite Video
3. S - Video (Super Video)
4. Analog Video

Question 14

What is Component Video?

Answer 14

• store and transmit 3 component signals
• simplest form is the collection of R,G and B
• cameras and other devices use three different connectors or wires to transmit
• RGB converted to YCbCr if same set of colors for color monitor as well as B/W

Question 15

What is Composite Video?

Answer 15

• transmits single signal over just one wire
• reduces cable/channel requirements
• luminance-chrominance format used for transmission
• Bandwidth split and allocated to luminance and chrominance
• Luminance has more bandwidth than chrominance
• transmitted via single RCA jack
• signals within the single wire interfere with each other

Question 16

What is S-Video?

Answer 16

• an analog signal format
• transmits luminance and chrominance portions over different wires
• improves picture quality as compared to composite video
• more expensive
• uses a 4 pin mini-DIN connector

Question 17

What is Analog Video?

Answer 17

• info as a continuous flow of analog data

Question 18

Enhanced Definition Television Standard(EDTV):

Answer 18

• refers to the resolution 480p
• enhancement to SDTV
• vertical and horizontal resolutions improved
• uses 4:3 aspect ratio for std. TV and 16:9 for widescreen
• 30 frames per sec

Question 19

Consultative Committee for International Radio communication(CCIR):

Answer 19

• historically related to analog TV systems
• has 2 options: NTSC and PAL
• max bandwidth for each TV channel 6MHz
• Aspect ratio -> 4:3
• Frame rate is 25fps