Difference between revisions of "MTD2 class 8"

Revision as of 03:11, 10 October 2006

In Class

• Audio Effects Presentations
• Intro to digital thoery
• Rendering in Premiere

Digital Theory

Word of the Day Analog How stuff works - How Analog and Digital Recording Works

Analog vs. Digital the arguments in a nutshell

* 'anything in quotes is what I like to call an opinion

Other Opinions

analog winner http://www.segall.com/atr.html

analog winner http://www.digido.com/analog_versus_digital.html

comparison http://www.outersound.com/osu/recording/

ana-dig.html Number Systems

Binary Numbers

As Humans we use a 10 base numbering system. For machines this numbering system is impractical.

Gottfried Willheml von Leibnitz devised the binary number system in 1679

Converting Binary Numbers

Binary->Decimal

   110102 = (1 * 24) + (1 * 23) + (0 * 22) + (1 * 21) + (0 * 20) = 1610 + 810 +  0 + 210 + 0 = 2610

Dividing by two

for more info see Dr. Dave's Class readings (i beleive it's in week 2)Daves text

Base2

Each new bit doubles the number of intervals.

Binary Math

Binary Math http://www.ibiblio.org/obp/electricCircuits/Digital/DIGI_2.html What can one byte (8 bits) store? 2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 1 1 1 1 1 1 1 1 128 64 32 16 8 4 2 1 128+64+32+16+8+4+2+1 = 255

What about negative numbers? Signed Magnitude

Use the first bit as the equivalent of a +/- sign.

http://www.math.grin.edu/~rebelsky/Courses/152/97F/Readings/student-binary.html 510 in 8 bit binary 00000101

-510 in 8 bit binary Signed Magnitude 10000101 (make sure that the circuit knows you are using singed magitude otherwise this couls be interprerad as 113)

Now what can one byte (8 bits) store? +/- 2^6 2^5 2^4 2^3 2^2 2^1 2^0 0 1 1 1 1 1 1 1 + 64 32 16 8 4 2 1 64+32+16+8+4+2+1 = 127 or +/- 2^6 2^5 2^4 2^3 2^2 2^1 2^0 1 1 1 1 1 1 1 1 - 64 32 16 8 4 2 1 -64+32+16+8+4+2+1 = -127

One's Compliment

One's Compliment uses regulgar binary numbers to represent positive numbers. To make that numer negative you just filp all the bits from 1 to 0 or 0 to 1. 510 in 8 bit binary 00000101

-510 in 8 bit binary One's Compliment 11111010

Two's Compliment

Same as One's Compliment bit add one to negative numbers 510 in 8 bit binary 00000101

-510 in 8 bit binary Two's Compliment 11111011

To figure out the sign of the answer we mustcheck the MSB (most significant bit).If MSB is 0 number is positive, intepretnormally If MSB is 1 number is negative

   * complement all bits
   * add 1
   * interpret as negative number 

Sampling theory

sampling process

Bit Depth

over 24 bit used mainly for internal processing and really high end audio equipment 24 bit Professional recording and internal processing 16 bit CD quality audio (not so good for processing) 8 bit Smaller size used for consumer voice stuff and multimedia

Sampling Rates

Some Common Smapling Rates

File Size per Sampling rate and Bit Depth

  Note : Dropping the Sampling Rate or Bit Depth by half leads to half the file size

File formats

CD Formats

• RedBook Audio standard CD audio format
• CDROM-XA (eXtended Archetecture) audio and data

Premiere Audio Demo

Premiere Audio Demo

Homework

1. Read Chapter 3 in Sound Design for Interactive Media
2. Render and Post and link a rought cut of your Story Boards with Audio
3. review for MTD2 Quiz 3