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Understanding File Compression

In this lesson, students will learn about file compression and why it is so important in today’s technology.

This lesson could form the basis of a 45 min - 1 hr class and by the end of the lesson students will have learned:

What is file Compression?
What are the different types of file compression?
What is a codec?
How do codecs relate to Audio and Video files?
How to optimize your file with the correct file compression, codec, frame size, audio codec for playback on internet sites such as YouTube, Facebook etc.

What you’ll need

Videos from students Cameras / Camcorder (MP4 or WMV)
Audio files (TrakPacks from TrakAx or students’ own music from CDs / iTunes / Amazon etc.)
TrakAxPC Pro

Resources

These may vary in suitability depending on age group.

Provides an explanation and definition of data compression
http://en.wikipedia.org/wiki/Data_compression

Understanding Lossless Compression
http://en.wikipedia.org/wiki/Lossless_data_compression

Understanding Lossy compression
http://en.wikipedia.org/wiki/Lossy_data_compression

A very useful resource for understanding the basics of compression and codecs
http://desktopvideo.about.com/od/glossary/g/vidcompression.htm

Learn how file compression works
http://www.howstuffworks.com/file-compression.htm

YouTube Compression
http://www.google.com/support/youtube/bin/answer.py?answer=132460&topic=16612&hl=en-US

Compressing video for an iPod
http://blogs.oreilly.com/digitalmedia/2005/10/compressing-video-for-the-ipod-4.html

Lesson Structure

Class Activity 1

Teacher explains to Students what file compression is and why it is important in today’s technology market (e.g. how it relates to software, media playing devices, PC’s, etc.) - see resources above for more information. Students will understand why file compression is used in software applications and what are the different types of compression used.

By the end of this activity, Students should have a basic understanding of:

What file Compression is and the different types of compression?
What is a codec and how they relate to Audio and Video files?
How to optimize your file with the correct file compression, codec, frame size, audio codec for playback on internet sites such as YouTube, Facebook etc.

Class Activity 2

Students begin to make a mix in TrakAxPC using Audio files. Render the mix using MP3 / FLAC compression and WMA Lossless and then compare the file sizes and quality of each render file.

Class Activity 3

Students place a video file in TrakAxPC. Students can render this video file at different audio and video compressions and codecs such as MP4 (MPEG / H.264), AVI and WMV, while also using different frame rates and frames per second. Students should then compare the quality and file size of each rendered file.

Class Activity 4

Students place a video file in TrakAxPC and then render the file at YouTube HD setting. Students watch the video play in the HD setting in YouTube. Students should understand that the file has been compressed and optimized to play in this setting on YouTube (codec, frame size etc.).

Class Activity 5

Students take an audio / video file and compress it so that it will play on their iPod, iPhone, iTouch, PSP or other media playing devices and understand why these codec are important in order for them to play correctly on these devices.

Class Activity 6 – Review

Each group or student reviews the various files they have created and discuss differences between each file format and size.

Students can discuss which file formats provided the best quality, which were poor quality, too large, etc.

Students can submit a short written piece on what they have learned about compression and codecs and the positive and negative effects they can have on software, PC’s, media playing devices, Hard-Drive space, etc.