What is compression?
- Compression is the process of reducing the bits required to store a file
- You usually compress things to put them on the internet
- This is to save bandwidth and speed up the download
- You normally need to compress pictures to send them in an email
- Compressing the picture means less information needs to be sent
- There are two types of compression:
- This type of compression reduces the file size by getting rid of bits and hoping you won’t notice
- It is used for multimedia: Pictures, music and videos
- Usually it doesn’t look (or sound) any different because your brain fills in the missing information
- To compress a picture in this way, the computer looks at pixels next to each other and if they are similar colours, it says they are both the same
- After doing this, it ends up storing less data
- The .mp3 music format and .jpg picture format use lossy compression
- Every time you save something as a .jpg the quality decreases
- It’s completely evil if you ask me! .jpg isn’t my favourite picture format any more! I’m a .png person now, and this is why:
- In lossless compression, the file size is reduced without losing any quality
- The original file stays completely unchanged
- It is used for text, programs and program data (like videogame save data) because they are all things you don’t want to lose small parts of
- The .png picture format uses lossless compression, which is why it’s my new favourite!
- I’ve seen two GCSE computing papers which have a question about compression (and that’s quite a lot given that at the time of writing only two GCSE computing papers have ever been published)
- They both ask for two ways for a kid to reduce the file size of a picture to send it in an email
- One way is to compress it
- The other way is to reduce the dimensions of the image (make it less tall and wide)
I tried saving things as .jpg over and over again to create a lossy compression slideshow for you all to enjoy, but I just couldn’t notice any difference! (Stupid brain, filling in!)
Sorry about that.
Return 0; //The end.
Related articles. You know how this works by now.
- Data Compression (computersight.com)
- GCSE Computing Revision – Data Sizes (mattg99.wordpress.com) <–
- GCSE Computing Revision – Programming Setup (mattg99.wordpress.com) <–
- GCSE Computing Revision – Converting to and from Binary Numbers and Understanding Binary (mattg99.wordpress.com) <–
- JPEG Compression (pixiq.com)
- Which File Type Do I Use? (ourlearningcommons.wordpress.com)
- GCSE Computing Revision – Types of Testing and Types of Test Data (mattg99.wordpress.com) <–