Difference between revisions of "MTD2 class 8"
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==In Class== | ==In Class== | ||
Revision as of 20:35, 5 March 2006
Contents
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 Analog Digital Good - Infinite dynamic quantization (infinite resolution)
Quantization error
fix - more bit depth/oversampling Good? - The warming effects 'we're used' to from tape compression. Good?-'Perfect' reproduction of high frequencies - 'soundz harsh'
fix - 'using warm-sounding mikes and preamps (tubes)' Bad - Tape noise and generation loss Good - 'no generation loss' Bad - 'Cheap recording sound cheap' Good - 'cheap recordings sound good but digital' * '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 Hexadecimal
Base 16 Decimal
Base 10 Octal
Base 8 Binary
Base 2 0 0 0 0000 1 1 1 0001 2 2 2 0010 3 3 3 0011 4 4 4 0100 5 5 5 0101 6 6 6 0110 7 7 7 0111 8 8 10 1000 9 9 11 1001 A 10 12 1010 B 11 13 1011 C 12 14 1100 D 13 15 1101 E 14 16 1110 F 15 17 1111
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 integer remainder bin# 26 26/2 0 0 13/2 1 1 0 6/2 0 0 1 0 3/2 1 1 0 1 0 1/2 1 1 1 0 1 0 0/2 that's it kids
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. 20 =1 21 =2 22 =4 23 =8 24 =16 25 =32 26 =64 27 =128 28 =256 29 =512 210 =1024 211 =2048 212 =4096 213 =8192 214 =16384 215 =32768 216 =65536 217 =131072 218 =262144 219 =524288 220 =1048576 221 =2097152 222 =4194304 223 =8388608 224 =16777216
Name
Abbr.
Size Kilo
K
2^10 = 1,024 Mega
M
2^20 = 1,048,576 Giga
G
2^30 = 1,073,741,824 Tera
T
2^40 = 1,099,511,627,776 Peta
P
2^50 = 1,125,899,906,842,624 Exa
E
2^60 = 1,152,921,504,606,846,976 Zetta
Z
2^70 = 1,180,591,620,717,411,303,424 Yotta
Y
2^80 = 1,208,925,819,614,629,174,706,176
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
192kHz Professional recording and new fancy sound cards 96kHz Professional recording (New CD/DVD format) 48 kHz Professional recording (found mainly on DAT recorders used for film) 44.1 kHz CD quality Audio 22 kHz Multimedia/ Games 11 kHz Multimedia/ Games
File Size per Sampling rate and Bit Depth Sample Rate Bit Width File Size per minute 96 kHz 24-bit Stereo 33.0 MB 44.1 kHz 16-bit Stereo 10.5 MB 44.1 kHz 16-bit Mono 5.3 MB 44.1 kHz 8-bit Stereo 5.3 MB 44.1 kHz 8-bit Mono 2.6 MB 22 kHz 16-bit Stereo 5.3 MB 22 kHz 16-bit Mono 2.6 MB 22 kHz 8-bit Stereo 2.6 MB 22 kHz 8-bit Mono 1.3 MB 11 kHz 16-bit Stereo 2.6 MB 11 kHz 16-bit Mono 1.3 MB 11 kHz 8-bit Stereo 1.3 MB 11 kHz 8-bit Mono 660 KB
Note : Dropping the Sampling Rate or Bit Depth by half leads to half the file size
File formats name ext. info aiff .aif audio interchange file format (mac native) supports markers and regions sd2 .sd2 sound designer 2 (digidesign native) supports markers and regions wave .wav wave file (Microsoft) many different formats most support markerz and regions au-law .au or .aul au-law file (unix native) supports compression RAM .ram or .ra Real audio File supports compression and streaming Mpeg3 .mp3 Mpeg layer 3 supports vairble compression and streaming (AMP) AAC .aac Mpeg2 Advanced Audio Coding AC-3 standard NEW not supported yet
http://www.execpc.com/%7Ereal/aac/index.html MIDI .mid not and audio format Modular (MOD) .mod kinda an audio format (used mainly for games) ASF wmv .asf .wmv windows Media and Advanced Streaming Format Microsoft supports variable compression streaming video encryption
CD Formats
RedBook Audio standard CD audio format
CDROM-XA (eXtended Archetecture) audio and data
Homework
- Read Chapter 3 in Sound Design for Interactive Media
- Render and Post and link a rought cut of your Story Boards with Audio