Properties And Formats Of Media Files Flashcards
What is Compression
Compression is taking something big and making it smaller.
What does compression allow you to do across a network and why?
Faster transmission
(Smaller files take less time to transmit)
Why are files commonly compressed?
To save storage
What is lossy compression?
File sizes are reduced by permanently deleting some data from the file.
What is a disadvantage of lossy compression?
Data cannot be restored and so the effects of the compression cannot be undone. Compressed to lower quality.
Where is lossy compression commonly used?
Video, audio and image compression
E.g JPG
What is an advantage of lossy compression
File sizes are reduced much more using lossy compression than lossless
What is lossless compression?
The computer packs the data into less space.
What is an advantage of lossless compression
No data loss
Can be decompressed back to its original form.
What commonly uses lossless compression?
Image, video and audio formats
PNG
ZIP
What is a disadvantage of lossless compression?
File sizes are generally larger than those compressed with lossy compression
What are Bitmap images (Raster images)?
Made up of many individual pixels formed into a grid to create the image
What are Vector images?
The co-ordinates of point on a page and connected with straight and curved paths that are calculated mathematically
What is an advantage of a raster image?
Can store complex colours
What is a disadvantage of raster images?
When you take a raster image and resize it to be bigger, it will start to look pixelated.
What is an advantage of vector images?
You can resize your image without losing quality
What is a disadvantage of vector images?
Can only use flat colours or simple gradients
What are the two different ways to look at ‘the number of pixels’?
- Pixel dimensions
- Dots per inch (pixels per inch
Examples of common pixel dimensions?
-1920x1080
-320x480
-250x250
+1080x1080
What does Dots per inch (DPI)/Pixels per inch (PPI) measure?
How many pixels of colour are used per inch of thd image
What is DPI resolution commonly used for and the standard resolution?
-Images for printing
- 300 DPI
What is PPI resolution commonly used for and the standard resolution?
- Computer displays
- 72 PPI
What is TIFF and how is it used?
Lossless compressed raster file format that is commonly used for high-quality printing and scanning
What is a disadvantage of TIFF?
doesn’t compress as effectively as other formats, which results in large file sizes
Most web browsers can’t use it
What is JPG and how is it used?
lossy compressed raster file format commonly used for online photography and artwork as well as low-quality printing
What is an advantage of JPG?
Useful for displaying images on websites
What is a disadvantage of JPG?
Reduces quality of the image creating artefacts a d pixelation
What is GIF and how is it used?
Lossless compressed raster file format commonly used for simple web graphics and embedding animations in web pages.
What is colour depth?
Defines how many colours can be used.
What is a disadvantage of GIF?
Low colour depth
Not good for things like photographs
What is PNG and how is it used?
lossless compressed raster file format commonly used for high-quality images that require transparency
