Final Concepts Flashcards

1
Q

Frame rate

A

Indicates how speed is counted; measured in frames per second

ex. 29.97 df

can associate with time signature

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2
Q

Non-drop frame

A

The standard way to count time code; 0-29 and back to 0

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3
Q

Drop frame

A

Method of counting time code that drops time code reference numbers (not actual frames) at specific intervals

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4
Q

What frames does drop frame timing drop?

A

Drops 2 frames every minute except on the tens minutes
Ex. no frames dropped on minute 0, 10, 20, 20, etc.

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5
Q

How are frames counted in time code?

A

Frames begin at 0 and go to 29
No frame 30, just like we count from 59 seconds to 0 when the minute goes up
There is no frame 29.97, so 29.97 frame rate is counted like 30 fps but slowed down 0.1%

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6
Q

2-pop

A

One frame sine wave tone used to sync with the number 2 of a film countdown (the visual 2 is only 1 frame long); added during postproduction

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7
Q

head pop

A

Placed exactly 2 seconds BEFORE the FFOA- ensures correct sync between sound and picture

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8
Q

tail pop

A

Placed exactly 2 seconds AFTER the LFOA- ensures correct sync between sound and video is maintained throughout the whole reel

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9
Q

Release print

A

film shipped to the theater; sound and picture are married together with head and tail pops

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10
Q

Blackburst generator

A

(similar to a word clock generator) dictates the accuracy of video playback system (aka VIDEO REFERENCE/ VID REF)
Common speeds: 60 Hz, 59.94 Hz, 50 Hz

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11
Q

LTC

A

linear timecode; When the SMPTE timecode is encoded as an audio signal and recorded on a dedicated audio track (TC track)
TC used to have one machine “chase” (or follow) another machine’s timecode
The connection port is often XLR or BNC

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12
Q

NTSC

A

National Television Systems Committee; First TV broadcast made in 1939; Resolution is 525 lines horizontal displayed at 30 times a second using 2:1 interleave (i)
24fps; Based on 60Hz AC system

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13
Q

PAL

A

European version of NTSC; Based on 50Hz AC system; PAL is 25fps; Standard resolution is 325 interlaced 25 times a second; PAL is considered to handle color better than NTSC

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14
Q

Pulldown

A

Change in playback speed applied to sound element of a project when it needs to be converted to a format running at a different speed; usually associated with transferring film sound to a video medium due to the different speed references

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15
Q

What are the pulldown references for film?

A

30 fps 60 Hz

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16
Q

What are the pulldown references for NTSC video?

A

29.97 fps 59.94 Hz

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17
Q

What is the speed difference from film to NTSC?

A

0.1%

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18
Q

If sound is recorded at a 30fps @ 60Hz using a sampling rate of 48kHz, what happens to the sampling rate to have it play back accurately when referencing 29.97fps @ 59.94Hz?

A

It gets slowed down by 0.1%

ex. 48,000 Hz * .001 = 48 Hz
48,000 Hz - 48 Hz = 47,952 Hz

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19
Q

What can we do DURING RECORDING so that your END result is a sampling rate of 48kHz?

A

Sound record ON LOCATION can be 48,000 Hz * 1.01% (.1% FASTER than our pull-down) = 48.048 Hz
After your film is transferred to video, and you slow down your sound 0.1%, you have a sampling rate of 48,000Hz at a speed of 29.97 fps @ 59.94 Hz

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20
Q

Pulldown

A

Opposite of an audio pull-down; when the sound element (operating at NTSC video speed) needs to be relayed or tied to an element running at FILM speed; commonly, going from a TC rate of 29.97 to a TC 30 fps

21
Q

What is multichannel audio?

A

any amount of channels more than mono; stereo, 5.1, 7.1.2, etc

22
Q

What is surround?

A

extension of multi channel audio that includes some form of audio that is emitted from B the listener

23
Q

Discrete surround

A

uses independent channels to feed each speaker, like sending multitrack outputs to dedicated speaker; for 5.1 system, there are 6 discrete channels; usual speaker assignments include L, R, C, Ls, Rs, and LFE

24
Q

What are the main discrete formats and what kind of compression formats do they use?

A

Dolby Digital, Digital Theatre systems, Sony Dynamic Digital Sound; all use Lossy audio data compression and have different bit rates

25
How is discrete surround monitored?
5 discrete channels using 5-full bandwidth 20-20kHz speakers and one LFE speaker emitting frequencies from 20Hz to 120Hz
26
Matrix
-Use phase to encode multiple channels into a stereo signal. -Designed for delivery to analog formats -The audio plays back as normal stereo when not decoded -When decoded, various outputs are available such as LCR and mono surround. -Dolby Surround Stereo, often referred to as Pro Logic
27
Object based
uses additional speakers along with additional audio channels that rely on metadata to render info appropriately for replay
28
What is the SMPTE 5.1 channel configuration?
L-R-C-LFE-Ls-Rs
29
LFE vs. bass management
when full bandwidth speakers are not used, low frequency information can be routed to the sub-woofer with a built in crossover; we sometimes see this on systems using speakers with limited bandwidth like a 2.1 system.
30
What are the origins of LFE?
devised for 70mm movie productions to deliver a separate bass signal to one or more additional subwoofers placed behind the movie screen; deep bass effects can be added to movie soundtracks without having to upgrade the existing speakers and amplifiers in the three main screen channels; LFE Channel is BRICKWALL filtered at 120Hz
31
What is the difference between LFE and subwoofer?
LFE channel is used to carry additional Bass information in the Dolby Digital Program while the subwoofer output represents how some or all of the bass information will be reproduced
32
Top and tail editing
Top editing is cutting off everything before the playhead (beginning of clip); tail editing is cutting off everything after playhead (end of clip)
33
What are the frame rate for film (visual)?
24 fps
34
What is the speed base/line frequency for film (visual and sound)?
60Hz
35
What is the frame rate for film (sound)?
30 fps
36
Time code
positional reference for material on a device, measured in hours:minutes:seconds;frames
37
What is the reference point for dBu?
0 dBu=.775 Volts
38
What is the reference point for dBV?
0dBV=1 Volt
39
dBSPL
refers to decibels in relation to sound pressure level
40
dBFS
decibels relative to full scale; highest level is 0 dBFS, any level higher than this will distort and create odd harmonics
41
What is the reference point for dBFS?
-20 dBFS=0 VU
42
lossless encoding
allows for the quality of the uncompressed format but with a reduced file size same amount of storage required regardless of content: one minute of silence requires the same amount as one minute of a fully produced song requires time to analyze and encode information (plus extra time to decode the information, which can delay playback ex. think of an audio zip file.
43
uncompressed
audio file containing all the information from the original, without being encoded or compressed requires the same amount of storage and throughput regardless of content ex. one minute of recorded silence takes up the same amount of data space as one minute of a recorded Metallica song
44
lossy encoding
type of audio format that analyzes the sonic make up of audio and applies algorithms using psychoacoustic modeling (often called Perceptual Coding) to determine which portions of the frequency spectrum can be altered results in smaller file size less required disk space and faster data transmission (streaming) trade-off: reduced fidelity size is reduced, but accuracy is compromised; we can’t get back the accuracy once reduced
45
quantization
system assigns binary value to the sample value; bit depth determines the accuracy of quantizing
46
quantizing error
difference between the actual position of the sample and its represented value after quantizing the greater the number of bits, the LOWER the quantizing error the lower the number of bits, the GREATER the quantizing error
47
aliasing
if too few samples per cycle, the initial signal may be misrepresented and reproduced non accurate audio signal upon output in order to avoid aliasing, it’s important that the sampling rate be equal to at least 2x the highest audio frequency the system has to reproduce
48
What is the difference between DSP and Native processing?
DSP: processed on dedicated hardware Native Processing: processed by your computer’s CPU