[f2ict] File Types

File Types

Objectives

Learn about different common generic file types:

including:

Text file

Multimedia file

Subject | Subject

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Generic File Types

• File types that most computer system is able to read

  Not specific to operating system, types of computer etc. ​

File Extension

Subject | Subject

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• File extension helps the computer to identify what is the type of file

• File extension is the last few characters in a filename, starts with . (dot)​

Text-based files

​File type	​extension	​Description
​Text	​.txt	​Plain text file
​Rich text format	​.rtf	​Text file with simple formatting (e.g. color, fonts)
​MS Word Document	​.docx	Microsoft Word document, which is a proprietary format

Open Ended

Why .docx is not a generic file type?

Compressed archive

​File type	​extension	​Description
​zip file	​.zip	Most common compression file format
rar	.rar	RAR is also commonly seen compressed file format

Open Ended

We often compress files before transmitting, suggest the benefits of transmitting compressed files

Cannot directly use the file, must be decompressed before use

​

Problems

Smaller file size thus save storage and faster in terms of transmission

Multiple files are packed to one single file​

Benefits

Compression

​Compression reduce the size of file or data

Try to compress and decompress

using windows built-in zip handler

Open Ended

List some of the image file formats you can recall:

Image file

​File type	​extension	​Description
​JPEG	.jpg or .jpeg	​Standard image file format use in Internet
​PNG	​.png	​Portable Network Graphics, another Internet image standard
​GIF	​.gif	​Gif allows simple animated images

Image is also compressed

A typical jpeg from iPhone is compressed from about 20MB to 3MB so that you can store more!

​This compression is called lossy compression - which sacrifice some quality of picture and not recoverable.

Usually the size is further reduced if you send the picture with messaging app (by shrinking the image, reducing quality as well)

Audio/Video

​File type	​extension	​Description
​Wave	.wav	​Sound file
​MP3	​.mp3	Sound file, usually smaller in file size compare to wav
​MP4	​.mp4	Video format for Internet

Poll

For a typical 3-minutes MP3 song, guess how many storage space you need to store it?

• 100MB

• 1GB

• 300MB

• 3MB

Most Multimedia files are compressed

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Almost all video files are compressed. A raw, uncompressed 4K video requires about 1.5GB storage......

PER SECOND!!​

Video

Compare to an Audio CD, which capacity is about 650MB but stores only about 60 minutes of music, MP3 requires about 60MB to store the same length

Audio