DRAFT

Day 1

Today, Me and Nina decided to be a group named 'estalanaaa'h choose the topic of 'What is the cloud and why would you want?' We also registered our group on the student net.

Data Compression

What is data compression?
It is a term for a group of technologies that encodes large files to convert them into a smaller file.

What is a data compression ratio?

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

Why is data compression an important technique for the online world?
It is important as it helps compress data to be downloaded/uploaded to anything, from anything.

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 breaks up a file into smaller pieces, for storage or transmission, later on. It uses compression algorithms which allow it to copy the data exactly while Lossy data retrieves data that may be different from the orginal but is still similar to the original without anyone noticing.

Which method offers the greatest compression ratio?

the lossy compression is the offers the greatest compression. the rate or a lossy compression is about 5-6% while the rate of lossless compression ranges from 50-60%.

Why is human psychology and perception an important factor in methods of Lossy compression?
It is an important factor as it allows us to get rid of data that no one notices.

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

Audio:

MP3 - .mp3

WMA - .wma

Still Image:

DjVu - .djvu .djv

JPEG - .jpg .jpeg

Video:

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

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

1. What are some advantages of digital video

There is a reduced sensitivity to noise and interference, digital equipment performs tasks that are difficult or impossible to perform using analog technology efficiently and more economically.

2. What is meant by frame rate in video?

Frame rate can also be called frame frquency. TYhe frame rate is the number of frames or images that are shown per second.

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

No, not all videos/movies have the same frame rate. It depends on what is being filmed, for example a horse race would use more frames than an interview as the horse race has more movement in the video as an interview would be just two people talking.

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

Resolution is the sharpness and clarity of and image. the resolution is mesaured in pixels.

5. What is the colour system called RGB

Te colour system (RGB) consists of three colours; red, blue and green. the RGB system can also be called an 'additive' system, because it starts as black but then it absorbs light and colour is added

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

PAL(Phase Alternating Line), the analogue video format. it shows the way each colour part of information on a video signal is reversed in phase with each line.

NTSC (The National Television Standards Committee). it has 29.97 frames of video a second. each has 480 lines of vertical resolution out of a total of 525.

SECAM: (sequential color with memory) it is an analog television system. it uses memory to store lines of colour information.

7. Which standard do we use in Australia?

Australia uses PAL.

8. What is an IEEE 1394 port

Is like a usb port, which connects firewire connectors to the computer (the entry area of the device).

9. Why do digital video cameras use video compression

Digital video cameras use video compression to compress large amounts of data and to make it easier to handle. It's more clear, like the difference between raw and jpeg.

10. Describe what a codec is.

A codec is a microchip that compressess and decompresses data. Takes a raw file and turns it into a compressed file.

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

Generation loss is the loss iof quality and potential increase of file size between copies of data.Reducing the quality by photo copying a photo copy that was photo copied is an example of generation loss. The quality isn't as good as trhe original. It happens ion analog systems

Broadband

1.    What is broadband?
A telecommunications signal or device of greater bandwidth, than another standard signal or device.

2. What units are used to measure bandwidth?

Bits per second.

3. How much faster is broadband than dial up?

10 to 20 times faster.

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

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

Broadband operates faster than dial up and this gives it the advantage because it gives a speedy transfer of large data meaning downloading a video or a song may take a few minutes or seconds while on dial up it may take hours.

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.

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

 Over the years, more and more people use  mobile/fixed wireless and less use dial up but almost an equal amount of DSL and cable/fibre/satellite.

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

 

Less people use broadband that is less than 256kbps

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

 my computer wont let me.

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

my computer wont let me.

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

For sydney it's more spaced out, as not many people use it compared to the U.S location which is used more. It's like traffic on a two lane highway which was previously an eight lane highway.

Making Sound

1. Sound moves through what medium?
   Sound move through gases, solids and liquids.  
2. Briefly describe how a microphone works, in particular what does it gather and what does it produce?A microphone consists of a small membrane and a mechanism that translates movements and translates it into electrical waves.
3. What unit is used to measure sample size?Sample size is measured by bits.
4. What unit is used to measure sampling rate?The unit measured in sampliong rates is Hertz (Hz).

5.  How does sound quality vary with sample size and sample rate?If you increase the sample size it's better. If you increase sample rate, it's better. The more the better.

6.   What is another name for sample size?
Another name for sample size is sample format.

7. From the above information which offers better quality sound, FM radio or AM radio?FM Radio.
8. Why not record all sound in extremely high sample sizes and sample rates?Because it's to large of a file.

Ringtone 2



Audacity is an audio editor that is free and easy to use for both Mac OS X, GNU/Linux and Windows. It is one opf very few applications that can be put onto a USB. You can trim, change the speed or pitch of the sound or even record yourself. You can also make a ringtone, which I have done today.

Steps:

1. Open Audacity then go Project > Import Audio then select whatever song you want.
2. Trim the part of the song you want to use for your ringtone by selecting the part you want then going to Edit > Trim.
3. Go to Effects > Equalization
4. Follow the steps on http://manual.audacityteam.org/man/Tutorial_-_Making_Ringtones for Equalization.
5. Go to File > Export WAV and save it.