Digital Video

Question 1

Frame rates

Answer 1

• per second
• FILM - 24 fps (23.98 when shown on tv)
• PAL - 25 fps
• NTSC - 30 fps (29.97)

Question 2

Video Format

Answer 2

DV - low range (MiniDV, DVCPro-25, DVCAM)
SD - medium (DVCPro-50, Betacams)
HD - high quality (HDV, DVCPro-Hd)

Question 3

Image Size DV & SD

Answer 3

• In digital video, resolution is fixed @ 72 dpi (dots per square inch)
• DV - NTSC 720 x 480 (advantage: divisible by 4, video compression requires 4x4 pixel squares)
• DV - PAL 720 X 576 (higher in vertical, higher quality)
• SD - NTSC 720 x 486 (America)
• SD - PAL 720 x 576 (Europe)

Question 4

Image Size HD

Answer 4

• 1080i (interlaced - odd rows then even rows) [1920x1080]
• 1080p (progressive - all rows at once)
• HD 480i is what you see on tv
• HD 720i & 720p [1280x720]
• the 1st number refers to how many vertical lines of information are used
• All HD formats are 16:9

Question 5

Image Size HDV

Answer 5

• Will one day be new norm for HD
• 1440x1080
• JVC - 1280x720p
• Sony - 1920x1080i

Question 6

Aspect Ratio

Answer 6

• Width to Height of a picture
• 4:3 (pre-1950’s movies) (1.33 to 1)
• 16:9 (1.78 to 1)
• Epic movies (2.35:1)
• SD - 4:3
• HD - 16:9

Question 7

Letterboxing

Answer 7

Adding black bars at the top and bottom of the screen to fit a 16:9 image onto a 4:3 screen

Question 8

Pillarboxing

Answer 8

Adding black bars to the sides of the screen to fit a 4:3 image onto a 16:9 screen

Question 9

Analog Connections

Answer 9

• Composite (low)
• S-Video (medium)
• Component (high)
• Don’t cross digital and analog… can break equipment

Question 10

Digital Connections

Answer 10

• better than analog
• firewire vs SDI
• FW 4 pins, 4 wires
• SDI works for both standard and HD pictures, can carry just video or video w/ embedded audio
• SDI is the highest quality

Question 11

Data Rates

Answer 11

CD audio - 176KB/s
DV - 3.75 MB
SD uncompressed 8 bit - 20.2 MB
SD uncompressed 10 bit - 26.7
720p - 2.4 MB/s
1080i - 3.2 MB/s
1080i uncompressed - 160 MB/s

Question 12

Storage for 1 hour

Answer 12

DV 13GB
HDV 720p - 8.7
HDV 1080 i - 11.5
8 bit - 72.5
10 bit - 96
1080i - 560 gb

Question 13

RAID

Answer 13

Redundant Array of Inexpensive Disks
Disks running in parallel to record and play back vast amounts of info very quickly
data storage & data throughput
A best practice to play your video w/out dropping frames

Question 14

Color Sampling

Answer 14

Reduces the color info to reduce the video file size
Human much more responsive to grayscale changes than to color changes
Y-value: Luminance
The brightness level of each pixel

Question 15

Compression

Answer 15

Frame-based (each individual frame)
GOP-based (group of pictures - 12 to 15)
GOP smaller rates

Question 16

Time Code

Answer 16

A label that uniquely identifies each frame of video, expressed as hh:mm:ss:ff
essential to non-linear editing, coordinates of a map
2 types, no quality difference, just a label diff.
Drop-frame (exact match)
Non-drop frame (1 hour actually runs 1h4m20s)

Question 17

24 Frame Video

Answer 17

• 24 fps based on film model

* 1 of 3 main rates (24, 25, 30)

Question 18

24 Frame Video Advantages

Answer 18

• always shot progressively, clear & easy to see
• cleaner still frames
• file sizes smaller

Question 19

24 Frame Video Disadvantages

Answer 19

• if not the speed of final output (artificial frames)
FINAL VERDICT
• Shoot progressive video at frame rate it will be viewed (not 24

Question 20

Pulldown frame

Answer 20

• Duplicates frame before it
• Done for conversion
• Done in cadences (2:3:2:3, 2:2:2:4, etc.)
• Don’t remove frames

Question 21

Color & Video

Answer 21

everything is based on red, green & blue
RGB - computer
video
CMYK - printing

Question 22

White Balancing

Answer 22

• Adjusting colors inside the camera to compensate for lighting conditions so that white objects are recorded as white
• If not done, must do color correction inside software
• White is an equal amount of red, green & blue

Question 23

Scopes

Answer 23

• Histogram
• RGB Parade - Amount of red, green & blue
• Waveform Monitor - black, white & shades of gray
• Vector Scopes - further out from center, greater the saturation - opposite colors on opposite side of the circle

Question 24

Color Bars

Answer 24

• Make sure that info (colors) recorded and info (colors) played back are the same.
• Different color bar schemes for different formats
• Use them to calibrate scopes
• Not important for DV but essential for Analog

Question 25

Computer vs. Video Graphics

Answer 25

sdf

Question 26

Safety Areas

Answer 26

Full-Screen Action Safe - contains all essential action 5% in from all edges Title Safe - Contains all text and essential logos 10% in from all edges Why important? As a TV set gets older, it starts to zoom in more!

Question 27

Fixed Resolution

Answer 27

Video - fixed, as screen gets bigger, no more info, just bigger pixels 72 dpi, all graphics must be created at same size... 72 dpi Computer -

Question 28

Progressive vs Interlaced

Answer 28

``` progressive - all at once interlaced - even rows, then odd rose can't design the same quality of graphic lines must be thicker to compensate interlaced will appear flickering, disappearing any given pixel is only on 1/2 the time ```

Question 29

Best practices

Answer 29

Typefaces - 24 points Lines - 4 pixels wide Avoid fancy fonts with little curves or small lines (Baskerville, etc.) Avoid lines leaning close to horizontal or vertical

Question 30

Color Spaces

Answer 30

RGB - computer YUV - TV (much more restricted) Broadcast safe colors, since computers can create unbroadcastable colors, TV sets can't play them. Make sure all the colors are broadcast safe

Question 31

White vs Superwhite

Answer 31

In DV, Black = 0, White = 109% Broadcast safe - white 100% or lower Computer graphic white elves are 109% by default Why it's important to do color correction

Question 32

Audio Sample Rates

Answer 32

Measures the audio at a specific time and assigns an average value Determine frequency response Sample rate divided by 2 = frequency rate 32K = 32 samples per second 48K is standard for video up an octave doubles the frequency More samples = higher quality

Question 33

Bit Depth

Answer 33

Determines dynamic range (the distance between the softest and loudest passages) 0 = loudest 8 bit - 256 levels - 0 - -96 dB (internet & broadcast) 16-bit - 64,536 levels - 0 - -124 dB (CD audio, Video production & post production) 24-bit - 16,777,216 levels, 0 - -143 dB (movie theatre & dvd's) Human Hearing - n/a - 0 - -120 dB

Question 34

Wave Forms

Answer 34

shows volume of the audio thinner = quieter & vice versa WF's are connected with music. Not connected with music (pauses) ((so when editing look for where wave forms are thinnest))

Question 35

Audio Meters

Answer 35

shows loudness at any given instant Anything over 0 = distortion (red light) Make sure never light or even flicker red (can't fix distortion) Peak hold bars (last 3 seconds) to show highest sounds

Question 36

Reference Tones

Answer 36

Recorded at the beginning of tape to show how loud the audio is supposed to be. DV is recorded at -12 dB Analogue at 0 dB DigiBeta at - 20dB

Question 37

Setting right audio level

Answer 37

* Never exceed 0 dB EVER * Dialogue: -6 to -12 dB * Sound Effects: -12 to -18 dB * Music: -18 dB