Lab 3: Images and Sound
Lab Tasks:
- Visit The Wikimania Media Competition 2005
page. Download the high-resolution version of some photographs that you like.
- Open the photographs in Microsoft Photo Editor (under All Programs, Microsoft Office Tools). Save your files with
a new name, so you don't overwrite them.
- Notice that your files are in jpeg format. Try saving them as BMP, GIF, and any other formats you choose. Compare
the different file sizes; does this match what you know of the formats?
- Decrease the file resolution (this can be done by shrinking the file). Set the size to 50% (note that this shrinks
it by half in both dimensions) and compare the new file size to the old one. Repeat this several times, so the file
becomes much smaller. Compare the quality of the images and the various file sizes. What's the smallest file that
gives you a reasonable image?
- Try different combinations of resolutions and file formats, and make a table of the corresponding file sizes.
In particular, make sure you try BMP with the original resolution, half as much, a quarter, and so on.
- Record your voice in Sound Recorder (All Programs, Accessories, Entertainment). Save this in wav format, and make
a backup. Now try saving it with several different sampling rates and depths. Again, look at the file sizes; what do
you think of the audio quality?
- At Home: Take a CD of your favourite music artist, and rip it to your computer as MP3 at 320 kbps, 160 kbps, and
40 kbps. Can you tell the difference in sound quality between the CD and each of the copies?