Chapter 6 Review

Chapter 6 Review

Which of the following is the television broadcast standard for

the U.S. and Japan?

A. NTSCB. PALC. SECAM

Which of the following is the television broadcast standard for

most of the Asian countries?

A. NTSCB. PALC. NSTCD. SECAM

Which of the following compression methods works best with large areas

of solid color, such as in a cartoon animation?

A. QuickTime AnimationB. CinepakC. MPEG-1D. MPEG-2

Run Length Encoding (again)

• Some digital image compression algorithms, such as Run-length encoding (RLE) and JPEG compression are used. Codecs that use spatial compression and RLE are QuickTime Animation, QuickTime PlanarRGB, and Microsoft RLE. RLE works well for video with large areas of solid colors, such as most cartoon animation.

Which of the following compression methods achieves higher compression

for videos without much motion difference, such as for talking heads?

A. spatial compressionB. temporal compressionC. lossless compressionD. asymmetric compression

Which of the following is the most common color model for video?

A. RGBB. HSVC. CIE XYZD. luminance-chrominance

The frame rate for the NTSC system is _____ fps.

A. 24B. 25C. 28.9D. 29.97E. 30

The frame rate for the PAL system is _____ fps

A. 24B. 25C. 28.9D. 29.97E. 30

Frame rates (again)

• NTSC 29.97 • PAL 25 • SECAM 25 • Motion-picture film 24

The scan mode of a CRT computer monitor is _____.

A. interlacedB. progressive

• Computer monitors (CRTs) display the picture by displaying the lines from top to bottom in one pass, i.e. progressive scan– Same thing for flat panel computer displays LCD and

Plasma, but the refresh is so fast, it more of a burst than a progressive scan.

• Television monitors (CRTs) display in two passes, interlacing.– Allowed the broadcast signal to be “cut in half”– Otherwise, early signal would have been 15 fps.

The scan mode of a CRT television set is _____.

A. interlacedB. progressive

Clarification

• Plasma and LDC TV’s can be either progressive scan or interlaced.

• However, interlaced displays were only made because Broadcast TV is interlaced

• However, the plasma and LCD technology is better suited for progressive display

• We are seeing a shift to progressive signals and displays

Interlaced scan displays the frame by scanning the lines of a frame

_____.

A. in one pass from top to bottomB. in two passes: even-numbered lines in one pass and odd-numbered lines in the second

The comb-like artifact in a digital video, as shown here, occurs in the _____ video.

A. interlacedB. progressiveC. both A and B

Overscan is _____.

A. the area where critical content and text titles should be placedB. the area where the significant action takes placeC. the area that is outside of the television screen

True/False: There is no sampling and quantization involved in

capturing motion in digital video.

The frame size of a video refers to the video’s _____.

A. aspect ratioB. pixel aspect ratioC. resolutionD. ppi

True/False: The pixel per inch (ppi) is an important attribute for video

resolution and should be set correctly when working with digital

video in video-editing programs.

Clarification

• The frame size of a NTSC standard definition DV frame is 720 × 480 pixels. However, based on these numbers, its width to height ratio is 720:480, i.e, 3:2.

• It does not match the frame aspect ratio quoted above; it is neither 4:3 nor 16:9.

• What is missing here?

720 X 480 is 3:2

• For pixel aspect ratio = 0.9,width : height =

720 × 0.9 : 480 = 648 : 480

4:3• For pixel aspect ratio = 1.2,

width : height = 720 × 1.2 : 480 =

864 : 480 16:9

Pixel aspect ratio means _____.

A. the ratio of a frame’s width (in pixels) to the height (in pixels)B. the ratio of a frame’s height (in pixels) to the width (in pixels)C. the ratio of a pixel’s width to its heightD. the ratio of a pixel’s height to its width

The pixel aspect ratio of a wide-screen format DV is _____.

A. 4:3B. 16:9C. 1.0D. 0.9E. 1.2

The pixel aspect ratio of a standard format DV is _____.

A. 4:3B. 16:9C. 1.0D. 0.9E. 1.2

The frame aspect ratio of a wide-screen format DV is _____.

A. 4:3B. 16:9C. 1.0D. 0.9E. 1.2

The frame aspect ratio of a standard format DV is _____.

A. 4:3B. 16:9C. 1.0D. 0.9E. 1.2

The frame aspect ratio of a standard format DV is _____.

A. 4:3B. 16:9C. 1.0D. 0.9E. 1.2

True/False: The signals of digital television are broadcast or

transmitted digitally.

Clarification

• While one could argue that a signal wave (radio, electrical, etc.) is analog.

• Digital refers to how the signal is translated or interpreted.

• Hard drives can have arbitrary levels of magnetism but we interpret only two levels.– Magnetized, not magnetized

• If the signal is interpreted as binary, it’s a digital signal even though the signal itself can transmit analog data.

HDTV is in _____ format.

A. MPEG-1B. MPEG-2C. MPEG-3D. MPEG-4E. QuickTimeF. AVI

True/False: The frame aspect ratio of all six HDTV formats is 16:9.

Several high definition video camcorders are available to record 720p and 1080i

formats. The number in the format name—720 or 1080—designates the _____.

A. data rate of the videoB. width (in pixels) of the frame sizeC. height (in pixels) of the frame sizeD. ppi of the videoE. none of the above; they are model numbers of different companies

Several high definition video camcorders are available to record 720p and 1080i formats. The letters “p” and “i” in each format name stand for

_____ and _____ respectively.

A. pixels; inchesB. proprietary; infrastructureC. progressive; interlacedD. ppi; ppi

For a one-minute QuickTime video file with a file size of 100 MB, its playback on a 48x CD-ROM drive very likely will be _____. (Hint: The data rate for a 48x CD-ROM drive is about 7 MB/s.)

A. smoothB. choppy

Playback Bandwidth

• 100 MB needs to be moved in 60 seconds• 100MB/60 seconds = 1.66 MB/sec• If your playback or bandwidth is greater than

1.66, it’ll play smooth (on playback devices like DVD) or it can stream live (if you are downloading it).

For a five-second QuickTime video file with a file size of 100 MB, its playback on a 48x CD-ROM drive very likely will be _____. (Hint: The data rate for a 48x CD-ROM drive is about 7 MB/s.)

A. smoothB. choppy

Playback (again)

• 100MB needs to be moved in 5 seconds.

• 20MB per second.

• If device or network can decode/transfer 20MB second, you have two choices…– Wait (for download)– Skip data (choppy)

What does the term codec stand for?

Code and Decode

• Captured video is coded into a file format

• The file format needs to be decoded for playback or editing.

_____ refers to the type of compression method that aims at compacting individual frames.

A. asymmetric compressionB. lossless compressionC. lossy compressionD. spatial compressionE. temporal compression

_____ refers to the type of compression method that exploits the repetitious image

content over time.

A. asymmetric compressionB. lossless compressionC. lossy compressionD. spatial compressionE. temporal compression

_____ refers to the type of compression method in which the amount of time and the complexity

required to compress and decompress are significantly different.

A. asymmetric compressionB. lossless compressionC. lossy compressionD. spatial compressionE. temporal compression

_____ refers to the type of compression method that exploits the repetitious image

content over time.

A. asymmetric compressionB. lossless compressionC. lossy compressionD. spatial compressionE. temporal compression

_____ refers to the type of compression method that exploits the repetitious image

content over time.

A. asymmetric compressionB. lossless compressionC. lossy compressionD. spatial compressionE. temporal compression

symmetrical codec vs asymmetrical

• A symmetrical codec requires about the same amount of time to compress as to decompress a video.

• asymmetrical codecs: the amount of time required to compress and decompress are significantly different

• Fast decompression is preferable for video, – makes the playback much better—less wait time. – many codecs fall into the asymmetrical category

because it takes much longer to compress a video than to decompress.