EMS Creative iMedia Cambridge Nationals

1. File Formats
Lesson 7

2. Lesson Goals
 Know file formats used for images, audio and video
 Understand the use of file compression techniques
 Be able to describe properties and limitations of file formats
#limitation
#property

3. Viewing Digital Media
What devices can we use to view digital media files?

4. Digital Media
Know image, audio and video files
Be able to describe file formats
 Because there are so many different platforms which we can view
images, video and audio we need different file formats depending on the
device:
#limitation
#property

5. Digital Media
Know image, audio and video files
Be able to describe file formats
 Digital media devices are required to be able to play back the following:
 There are various different types of audio, image and video file and
each one is used for a specific reason or type of job.
 These different files will also vary in their quality, file size and the way
that the file is compressed.
#limitation
#property

6. Image File Formats
Watch the video and identify the good and bad features of five image file types:
GIF
PNG
EPS

7. File Type
EPS
Not good for sharp edges
Not great for text
Some colour detail is lost when compressed
Features millions colours
No colours are lost
No or little compression
PNG
Bad Points
Zooming in is good quality
Millions of colours
Compresses well
GIF
Good Points
Not compatiable with all applications
Large file sizes
Compresses well
Very small file size
Only has 256 colours
Doesn't show all colours
Millions of colours
Compresess well
Sharp edges
Not compatiable with all applications
Can only use in a few particular places
Doesn't lose colour or detail
Scalable to any size
Does not lose any colour quality
Can only open in certain software

8. Image Formats
Know image, audio and video files
Be able to describe file formats
 Different image file formats are used depending on the way in which you
want to use or display the image files but the quality varies greatly:
JPEG
GIF
#limitation
#property

9. What is compression?
Think of what the keyword may actually stand for…

10. Compression
Know image, audio and video files
Be able to describe file formats
 Digital media files can be either uncompressed or compressed:
This is the original file which is at the best
quality it could ever be. These files are
usually used just for storage because they
have massive file sizes.
Compressed
This is a file that has been made smaller to
store on things like portable devices. They
are poorer quality than uncompressed files
but have a much smaller file size.
#limitation
#property

11. Compression
Know image, audio and video files
Be able to describe file formats
 There are two main methods for compressing files:
This technique uses a formula which doesn’t
lose any of the original data so the quality of
lossless compression files is good.
Lossy
This technique gets rid of any data it thinks
is unnecessary. File sizes are much smaller
but the quality is poor compared to lossless.
#limitation
#property

12. Your Task
Know image, audio and video files
Be able to describe file formats
 Create a table showing properties and limitations of each image file:
 Big or small file size?
 Common file or not?
 Where is it used?
 State if the file is compressed or uncompressed.
File
Properties
Limitations
Compression
#limitation
#property

13. Key Words
 File Format
 The standard way that a digital media
file is stored on a computer
 Properties
 Features of the file format such as the
size and quality of the file
 Limitations
 Something that is a restriction on what
you are doing or want to do
 Compression
 Making a file smaller for broadcast on
different platforms