1. AUDIO
Guruh Fajar Shidik, M.Cs

2. Profile Lecturer Name GURUH FAJAR SHIDIK, S.kom, M.Cs Place /
Date Born
PONTIANAK / 15 FEBRUARI 1987
Research Interest
Artificial Intelligence, Algorithm Complexity,
Image Processing, Machine Learning,
Network Computing, Computer Security
Home Based
Post Graduate Information Technology
Academic
S1(2009) - Universitas Dian Nuswantoro (3.5 year)
S2(2011)- University Teknikal Malaysia Melaka ( 1 year)
S3(2012 ) - University Teknikal Malaysia Melaka ( Ongoing )
Publication
Journal & Conference
2013 – Performance Analysis of interface Bonding and Channel Bonding at Point to Point, Journal IEEE Latin America Transaction
2013 – Performance Evaluation of Bonding Technique at Wireless n - Journal TELKOMNIKA
2013 – An Improve Technique of Color Histogram in Image Clustering Using Image Matting, Journal JATIT
2012 – Auto Level Color Correction For Underwater Image Matching Optimization, - Journal IJCSNS
2012 – Performance Enhancement of Image Clustering Using Singular Value Decomposition in Color Histogram Content-Based Image Retrieval –Jurnal IJCCE
Analisa Pengaruh Perbedaan Medium Air Dan Udara Terhadap Kalibrasi Kamera Dengan Menggunakan Metode Zhang, Semantik
Framework untuk Mendeteksi Bot Net Kraken dan Conficker pada Jaringan Komputer, Semantik
International Technical Speaker
LASCCDCN Latin America Symposium on Clud Computing , Data Center and Network - MEXICO

3. Kontrak Kuliah
UAS : 30% Project / Writing Test UTS : 30% Writing Test Tugas : 40% *Tugas Lewat dari deadline – NO MARK !!
UTS 15%
UAS 25%
5% Tugas 1
10% Tugas 2
5% Tugas 3
20% Project Presentation

4. Introduction What is Sound?
Sound is a wave phenomenon like light, but is macroscopic and involves molecules of air being compressed and expanded under the action of some physical device.
Is a form of energy produced & transmitted by vibrating matter
Travels in waves
Travels more quickly through solids than liquids or gases

5. Vibration
Back and forth movement of molecules of matter

6. Compression
Where molecules are being pressed together as the sound waves move through matter
For example,
a wave travels through the springs just like sound waves travel through the air
the places where the springs are close together are like compressions in the air.

7. Sound Waves Alternating areas of high & low pressure in the air
ALL sound is carried through matter as sound waves
Sound waves move out in ALL directions from a vibrating object

8. Wavelength & Frequency
Wavelength is the distance between one part of a wave and the same part of the next wave
Frequency is the number of waves moving past a point in one second

9. Pitch A measure of how high or low a sound is.
Pitch depends on the frequency of a sound wave
For example,
Low pitch
Low frequency
Longer wavelength
High pitch
High frequency
Shorter wavelength

10. Volume Amount of sound energy reaching your ears Depends on:
How far the vibrating object is moving as it goes back and forth
How far you are from the source of a sound
Volume Control

11. Sound and Instruments
Instruments can be played at different pitches by changing lengths of different parts.
For example,
Another way to make different pitches is to change the thickness of the material that vibrates.

12. Format Audio

13. 3 Categories of Audio Files
There are 3 categories in which certain Audio files belong to.
Uncompressed: Audio files that are not compressed and are capable of having a large file size. Ex) .Wav
Lossless: Audio files that are compressed but doesn’t lose any quality to the file. Ex) .WMA
Lossy: Audio files that lose some quality when being compressed. Ex) .Mp3

14. Most common audio files
The most common types of audio files that are still being used today are .Wav files and .Mp3 files.
Mp3 files are the most popular because it’s used for downloading and storing music into your computer, CD player, or mp3 player. Wave files are used for storing CD-quality sound files, which can be large in size.

15. Digital Audio – File Formats
Apple
Audio Interchange File Format – AIFF
.AIF or .AIFF or .AIFC
8-bit, mono
8-bit, stereo
16-bit, mono
16-bit, stereo
32-bit, mono
32-bit, stereo

16. Apples sound formats Sound
.AIF files support a range of sampling rates 8kHz, 11kHz, 22kHz, 44kHz and 48kHz
compression of between 2 to 1 and 4 to 1 is available using suitable codecs but causes reduction in sound quality
.AIFC is AIFF with IMA compression
Sound
.SND

17. Other platforms SUN Sun Audio - (NeXT Audio) .AU
.AU files support only 8kHz, 11kHz and 44kHz sampling rates
8-bit, mono
8-bit, stereo
u-law, mono
u-law, stereo
A-law, mono
A-law, stereo
Java/Web, mono

18. Windows Wave and PCM Adaptive Delta Pulse Code Modulation – ADPCM
CCITT
All WAV (sometimes .PCM for PCM files)
µ-law, mono
µ-law, stereo
A-law, mono
A-law, stereo
IMA ADPCM 8kHz, 4-bit, mono
IMA ADPCM 8kHz, 4-bit, stereo
IMA ADPCM 8kHz, 8-bit, mono
IMA ADPCM 8kHz, 8-bit, stereo
IMA ADPCM 8kHz, 16-bit, mono
IMA ADPCM 8kHz, 16-bit, stereo

19. Windows sound formats continued
.WAV files support a range of sampling rates 8kHz, 11kHz, 22kHz, 44kHz and 48kHz
also a version with Microsoft’s own compression algorithm
Can exceed CD quality
Higher quality – Greater storage penalty

20. Windows Media Audio A streaming audio format
Designed for network transfer and play- before-download replay
Available for UNIX, Mac and Windows
Formats:
.asf, .wma, .wmv
wide range of quality options

21. Real Audio A streaming audio format
Designed for network transfer and play- before-download replay
Available for UNIX, Mac and Windows
Formats:
.RA
also as part of .RM, .RAM
wide range of quality options

22. Other Streaming Formats
In addition there are other streaming formats including:
LiveAudio - .LA
LiquidAudio - .LQT
Streamworks - .MPA
Shockwave Audio - .SWA
The players for many of these can also play non-streaming audio
Most streaming formats deliver mono sound at 8kHz or less

23. MP3
MPEG Audio Layer-3
In 1987, the IIS started to work on perceptual audio coding in the framework of the EUREKA project EU147, Digital Audio Broadcasting (DAB).
In a joint co-operation with the University of Erlangen (Prof. Dieter Seitzer), the IIS finally devised a very powerful algorithm that is standardised as ISO-MPEG Audio Layer-3 (IS and IS ) MPEG2

24. MP3 cont 2
By using MPEG audio coding, you may shrink down the original sound data from a CD by a factor of 12, without losing sound quality.
Without data reduction, digital audio signals typically consist of 16 bit samples recorded at a sampling rate more than twice the actual audio bandwidth (e.g kHz for Compact Disks).
So you end up with more than Mb to represent just one second of stereo music in CD quality.

25. Typical Data Reduction Using MPEG Audio
1:4
MPEG Layer 1 (corresponds with 384 kbps for a stereo signal)
1:6...1:8
MPEG Layer 2 (corresponds with kbps for a stereo signal)
1:10...1:12
MPEG Layer 3 (corresponds with kbps for a stereo signal)
still maintaining the original CD sound quality.

26. Digitization Sample & Sample Rate

27. Analog/Digital Conversions
A Basic Digital Audio Setup
Microphone converts sound into an electrical signal
Anti-Alias “Brick Wall” filter removes very high frequencies from signal.
ADC periodically measures (samples) the amplitude of the analog signal, sending a stream of numbers to CPU.
DAC converts a stream of numbers into a stepped analog signal.
Smoothing filter removes staircase shape from signal.
Acoustical to Electrical to Digital (numerical) and back

28. Digitizing Sound
Sound is a continuous phenomenon; in the analog studio, it may be represented by a continuous electrical signal.
Digital computers can only handle finite, or discrete, information. So we must to convert sound from the analog to the digital domain. This is called sampling.
Sample = amplitude of a signal at some instant in time. Samples must be evenly spaced to have any meaning.
Sampling Rate = N samples/Second. Standard audio rates are 44.1 KHz for CD, 48 KHz for DAT/ADAT, 96K and 192K for professional digital recording.

29. Principles of Digitization
Why Digitize?
Microphones, video cameras produce analog signals (continuous-valued voltages)
To store audio or video data into a computer, we must digitize it by converting it into a stream of numbers.
Sound as analog signal
As I noted before sound is a continuous wave and as all natural phenomena is analog in nature. Microphones detect this analog input, which is nothing but a continuous sequence of voltages.
However, in order to store this input in a computer one has to convert it to a digital form, that is into 0s and 1s. Further a continuous wave has infinite resolution which cannot be represented in a computer.

30. Principles of Digitization
Sampling: Divide the horizontal axis (time) into discrete pieces
Quantization: Divide the vertical axis (signal strength - voltage) into pieces. For example, 8-bit quantization divides the vertical axis into 256 levels. 16 bit gives you levels. Lower the quantization, lower the quality of the sound
Digitization is achieved by recording or sampling the continuous sound wave at discrete points. The more frequently one samples the closer one gets to capturing the continuity of the wave.
Therefore, sampling is the process of dividing the horizontal (time-axis) into discrete points.
The other aspect of digitization is the measurement of the voltages at these discrete sampling points. As it turns out these values may be of arbitrary precision, that is we could have values containing small fractions or decimal numbers that take more bits to represent.
To cope with this arbitrary precision we use quantization which divides the vertical axis (signal strength or voltage) into discrete points.
For example, 8-bit quantization divides the axis into 256 discrete voltage levels.
While we are on the topic of quantization, it is important to note that not all quantization is uniform or linear. That is the vertical axis need not always be a linear scale, a non-linear logarithmic scale is used in mu-law encoding.

31. Common Sampling Rates
Which rates can represent the range of frequencies audible by (fresh) ears?
Sampling Rate
Uses
44.1 kHz (44100)
CD, DAT
48 kHz (48000)
DAT, DV, DVD-Video
96 kHz (96000)
DVD-Audio
22.05 kHz (22050)
Old samplers
Sound can be sampled as Monaural or Stereo
Most software can handle all these rates.

32. Sampling Considerations
Human hearing range not more than 20Hz to 20kHz
often only 40Hz to 15kHz in later life
Highest frequencies cannot be recorded at 11kHz sampling rate
Speech needs 4kHz to 8kHz sampling rate
Music needs 22kHz to 44kHz sampling
Too high a volume may incur clipping

33. Digital Audio – Sampling Size
The sample size is how much information is recorded at each sampling - also known as Bit Depth
The bit depth also influences sound quality
An 8 bit sample = 256 values
A 16 bit sample can store 65,536 values — A huge difference!
16 bit sampling gives a cleaner waveform with fewer steps

34. Digital Audio – The Trade-off
Mono, 8 bit, 11 kHz audio
1 byte ´ 11,000 ´ 1 second = 11 KB per second
11 KB/s ´ 60 second = 660 KB per minute
How much for Stereo and/or 16 bit and/or 44 kHz audio?

35. Stereo and Mono Mono, 16 bit, 22 kHz audio
2 bytes ´ 22,000 ´ 1 second = 44 KB per second
44 KB/s ´ 60 second = 2.64 MB per minute
Stereo, 16 bit, 44 kHz audio
2 bytes ´ 44,100 ´ 1 second ´ 2 = 176 KB per second
176 KB/s ´ 60 second = MB per minute

36. Digital Audio – Compression
Many flavours
ADPCM – 4:1
MicroSoft, MicroSoft IMA, Creative
CCITT – 2:1
A-law and -law
Audio MPEG – 20:1

37. Advantages and Disadvantages Of Compression
Smaller disk storage requirements
Disadvantages
Must be decompressed before use
Can take up to twice sound duration
Supported by good sound cards and specialist sound editing packages

38. Common Sample Sizes 8 - 12 bits OK for speech, some games
High Fidelity Music: 16 bits minimum
CD standard
Dynamic range is 96 dB, technically
Perfectly adequate for final product
Pro Audio: 20 or 24 bits
Better for recording, mixing, processing
Much better resolution for quiet sounds

39. What Should You Use?
Anything being recorded to CD must be 44.1KHz and 16 bits
Not all audio hardware can play at higher rates and greater resolutions
To keep things simple and maximize portability, use CD standard for now