Lesson 1: Choosing our topic

Mansi and I decided our topic today. We are doing What is Google +. We also researched and found this video that described google plus for us. http://www.youtube.com/watch?v=3KuIEIyXmrA

New Terms relating to audio files

Stereo

Commonly called stereo sound or sterophonic sound, stereophonic sound divides sounds across two channels (recorded on two separate sources) then the recorded sounds are mixed so that some elements are channeled to the left and others to the right. Stereophonic sound is generally considered the best sound technology of the 1950 and early 1960's.

Channel

A band of frequencies used in radio and television transmission, esp. as used by a particular station.

Track

A section of a record, compact disc, or cassette tape containing one song or piece of music.

Frequency 

The rate at which a vibration occurs that constitutes a wave, either in a material (as in sound waves), or in an electromagnetic field (as in radio waves and light), usually measured per second.

Hertz

The SI unit of frequency, equal to one cycle per second

Decibel

A unit used to measure the intensity of a sound or the power level of an electrical signal by comparing it.

Wav, mp3, aiff

Wav- An audio file format. Very accurate, but offers no compression, thus resulting in very large files.
mp3- A computer file format that compresses audio files up to a factor of 12 from a .wav file.
aiff- Apple’s native uncompressed audio file format created for the Macintosh computer, commonly used for the storage and transmission of digitally sampled sound.

What is Digital Data?

A computer is nothing more than a whole of witches

COMPUTER = SWITCHES 

1 is considered to be on and 0 is considered to be off.

8 bytes makes a byte.

0 or a 1 makes a bit.

1000 bytes is a kilobyte (KB)

1000 000 bytes is a 1000 KB which is a megabyte (MB)

1000 000 000 byte is 1000MB which is a gigabyte (GB)

1000 000 000 000 byte is 1000GB which is a terabyte (TB)

My name in ascii code J

Mansha: 000 1101000 0001000 1110001 0011000 1000000 0001

Singh: 001 0011000 1001000 1110000 0111000 1000 

There a 256 to arranging a bit. i.e, 2 to the power of 8.

Full Colour                    24 bits, 2 to the power of 24 = 16 million combinations for each pixel.

Sound                             16 bits, 2 to the power of 16 = 65536 combinations for music.

Data Compression

What is data compression?

Data compression is particularly useful in communications because it enables devices to transmit or store the same amount of data in fewer bits, There are a variety of data compression techniques, but only a few have been standardized.

What is a data compression ratio?

Data compression ratio, also known as compression power, is a computer term used to quantify the reduction in data-representation size produced by a data compression algorithm.

Why is data compression an important technique for the online world?

Data compression is an important technique for the online world as it helps decrease the the consumption of expensive resources such as hard drive space.

What is the difference between Lossy and Lossless data compression?

Lossless compression recreates a compressed file as an identical match to its original form.  All lossless compression uses techniques to break up a file into smaller segments, for storage or transmission, that get reassembled later. Lossy compression can't be used to compress anything that needs to be reproduced exactly.

Which method offers the greatest compression ratio?

Lossy.

Lossy data compression video codes generally provide the greatest compression ratio.

The video can be compressed at 100:1 ratio while audio and still images can often be compressed at 10:1.

The compression rate of lossy is about 5-6% while Lossless compression is about 50-60%

Why is human psychology and perception an important factor in methods of Lossy compression?

This is because in lossy compressions, very little of the information from a file is still there. Without the deception of how the human eye sees the difference of information, the file would be very different from the original. If we allow our mind to do so would be able to the errors in a lossy compression.

Name Lossy file formats for audio, still image and video format.

Audio:

MP3 - .mp3

MPEG-1 - .mp2

WMA - .wma

Still Image:

CPC - .cpc

DjVu - .djvu .djv

JPEG - .jpg .jpeg

Video:

DV - .dv .dif

MPEG-1 - .mpg .mpeg .mp2 .mp3 .mpa

MPEG-2 - .mpg .mpeg .mp2 .mp3 .m2v

Introduction to video

1.    What are some advantages of digital video

The advantages of digital video are:

• There is a reduced sensitivity to noise and interference.
• Digital equipment efficiently and economically perform tasks that are difficult or impossible to perform using analog technology.
• The application has many techniques for efficient retention of essential information such as compression.

2.    What is meant by frame rate in video

The frame-rate says how many images of a movie are displayed every second a movie is played.

The higher frame rate a movie has the smoother objects move in the movie.

3.    Are all videos/movies the same frame rate, explain your answer

No. Compare a movie with low framerate with a movie with higher framerate. The movie with high frame has more frames for the same number of seconds film. The movie with higher framerate will also be stored in a larger file.  

4.    What is meant by resolution, how is it measured.

Resolution is the term used to describe the number of dots, or pixels, used to display an image. Higher resolutions mean that more pixels are used to create the image, resulting in a cleaner image. The display, or resolution on a monitor, is composed of thousands of pixels or dots.Resolution is measured in picture elements, or "pixels" for short.

5.    What is the colour system called RGB

RGB (red, green, and blue) refers to a system for representing the colors to be used on a computer display. 

6.    Explain the video standards PAL, NTSC, and SECAM, what are the main differences between them.

PAL: Stands for Phase Alternating Line, is the analogue video format.The name "Phase Alternating Line" describes the way that part of the colour information on the video signal is reversed in phase with each line, which automatically corrects phase errors in the transmission of the signal.

NTSC: The National Television Standards Committee. The NTSC format consists of 29.97 interlaced frames of video a second, each consisting of 480 lines of vertical resolution out of a total of 525 (the rest are used for sync, vertical retrace, and other data such as captioning)

SECAM: (Sequentiel Couleur avec Mémoire, French for "sequential color with memory") is an analog television system, using frequency modulation to encode chrominance information. It is so named because it uses memory to store lines of colour information, in order to eliminate the colour artifacts found on systems using the NTSC standard.

7.    Which standard do we use in Australia?

PAL

8.    What is an IEEE 1394 port

A very fast external bus standard that supports data transfer rates of up to 400Mbps (in 1394a) and 800Mbps (in 1394b). A single 1394 prort can be used to connect up 63 external devices.

9.    Why do digital video cameras use video compression

It uses video compression because of storage space and also in order to email, a file needs to be small.

10. Describe what a codec is.

Codec is a short name for coder-decoder, the software that takes a raw data file and turns it into a compressed file. Because compressed files only contain some of the data found in the original file, the codec is the necessary “translator” that decides what data makes it in to the compressed version and what data gets discarded.

11. What is meant by “generation loss”, where does it happen?

Generation loss refers to the loss of quality and potential increase of file size between subsequent copies of data. Anything that reduces the quality of the represenation when copying, and would cause further reduction in quality oin making a copy, can be considered a form of generation loss.

Discussion

We had a discussion in class today and sir showed/ told us the various topics to choose from. My partner is Mansi and our group name is Manshies.

Broadband and Bandwidth

1.    What is broadband?         

Broadband is the term used for any kind of fast Internet access. Broadband is designed to give a business or residential user instant Internet access 24 hours a day. Broadband's high speed gives you access to applications that are very slow.

2. What units are used to measure bandwidth?

Bits or Bytes
 

3. How much faster is broadband than dial up?

 

Broadband's is generally 10-20 times faster.

4. What are the speeds that broadband operates at compared to dial up?

A typical dial-up modem operates in the range of 30 kbit/s to 50 kbit/s . A broadband connection operates at between 256 kbit/s and 10 Mbit/s, depending on the service you have selected. 

5. What are some of the advantages of using a broadband connection to download something like a video compared to dial up? 

The advantages are that it can:

• allow you to transfer large files of text or graphics at high speeds,

• give you instant access to web pages,

• allow employees to telecommute,

• link several computers to the Internet through the same connection,

• make videoconferencing faster, smoother and more practical,

• save money by allowing a business to rationalise and centralise its servers.

• It's always on. As long as your computer is switched on you can be connected to the Internet. This means that you do not waste time dialing up and waiting for your modem to connect you to the Internet every time you go online.

• Your phone line is not tied up while using the Internet. Therefore there is no need to pay for a second phone line.

• There are no additional dial-up charges to connect each time you use the service.

Think of your connection to the internet as a tunnel that links your computer to the internet. A regular phone line can allow only a small amount of data to pass through at a time. In comparison, a broadband is a wider (or broader) tunnel, allowing a greater amount of information to pass through your connection at one time. The width of this tunnel is called "bandwidth." The more bandwidth you have, the faster you can move data.

6. Create an image in paint that illustrates how a high bandwidth connection can move more data compared to a dial up connection at a given time. 

 Have a look at the Australian Bureau of statistics website link below. It shows all of the internet usage in the last 3 years. Answer the following:

A] How has the type of access connection to the internet changed in recent years?

 

Of the 11.6 million internet subscribers in Australia, 77% are classified as Household subscribers while 23% are Business and government subscribers.

 

B] Can you identify a trend in advertised download speeds?

 

Internet speed

 

1. What is the speed of the connection from your computer to the Sydney location on the map?

 

 

2.  What is the speed of the connection from your computer to the U.S location on the map?

3. Why did the data transfer rates vary? [Hint: think of what happens when an eight lane highway moves into a two lane highway?]

Making Sound

1. Sound moves through what medium? Sound moves through air.
2. Briefly describe how a microphone works, in particular what does it gather and what does it produce? A microphone has a small membrane that vibrates with a mechanism that transletes movements of the membrane into electrical signals. The acoustic waves are turned into electrical waves by the microphone. Basically microphone goes from sound to electrcity.
3. What unit is used to measure sample size? Sample size in the number of digits in the digital representation of each sample. It is measured in Bits. (Bits are how the computer stores your information in) The sample size is how often a computer takes a sample of the audio.
4. What unit is used to measure sampling rate? Sample rate is basically the rate at which the samples are captured or played back. They are measured in Hertz (Hz).
5.   How does sound quality vary with sample size and sample rate? The sound quality will sound best when the sound is closest to its original sound. This is determined by how high the bit depth and sampling rate are. The more the sampling size the better the sound will be. The higher and greater the sampling rate the better the sound will be.
6. What is another name for sample size? Another common name for sample size is sample format.
7. From the above information which offers better quality sound, FM radio or AM radio? FM Radio (98k.bits/s) whilst AM (32kbits/s). FM is better as the higher the bit rate the better.
8. Why not record all sound in extremely high sample sizes and sample rates? This is because it takes up too much memory. It may cause our drives to fill up and slow our email.

Other notes : Bit Rate. Sample rate x sample size=kb/s. The more bits per second the better.

My ringtone (My heart Will Go On- Celine Dion)

Indian Remix

I also made a remix of some Indian songs, also using Audacity. I trimmed them to the time I wanted and added different effects like beats, change of speed.etc. The songs used are Ooh La La, Bipasha, Tujh Mein Rab Dikhta Hai and Chammak Challo.

How I made my ringtone

Using Audacity I made a ringtone with the song: My Heart Will Go On, by Celine Dion.
The steps I used were:
1. First I went to File> Import and chose the file I wanted to edit. 
2. Next I chose the part I wanted for my ringtone, which went for about 30 seconds.
3. I selected the part I wanted and trimmed the rest of the song.
4. After that, I used many affects which were:
Changing Speed: I increased the speed to 46.102, to make it sound like a chipmunk
Adding Echo: I did an echo, so that it would sound better.
Changing Pitch and Tempo: I added a beat to it, so that it would be more modern and less slow.
5. I also experinmented with other effects but they didn't sound good, so I didn't include them.
6. Next I went to File> Export and saved it as a WAV file.
7. My ringtone was now done!

How to make a ringtone in Audacity

Today in class we were introduced to a new type of software called Audacity. It is an audio editer which allows you to easily edit any music file. In class we had to make a ringtone from and these are the steps I used:

1. Click on File > Import > Audio. Next Select the song you want.
2. Select the portion you want to use for your ringtone (15-30 seconds approx). To crop the song, click audio track and drag a selction area (either left or right). You can select the length you want in the timeline track.
3. Many phones will loop the track, so if you want to hear it loop, hold down Shift, while clicked green play button. To stop it press yellow stop button.
4. ext you can be as creative as you like, using the many effects. Examoples include Changing Speed, Pitch, Tempo, Equilization.etc.
5. Once you are happy with your track, Click File> Export.
6. Now you have a ringtone!