Data compression definition gcse
How does compression software reduce file size?
Compression software reduces the size of a file stored on secondary storage.
There are two types of compression that can be applied to files:
- lossy A form of compression that reduces digital file sizes by removing data
lossless A form of compression that encodes digital files without losing detail.
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How does data compression work?
Data compression shrinks big files into much smaller ones.
It does this by getting rid of unnecessary data while retaining the information in the file.
Data compression can be expressed as a decrease in the number of bits required to illustrate data.
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Huffman Encoding
This is another lossless data compression model that makes use of the frequency of characters in a string.
For example, the string “a ratty character” has quite a lot of repeated letters in it.
In fact, it only contains 8 different characters - “a rtyche” (Note the space is important here!).
Now if we were to store this using 7-bit ASCII, this stri.
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Lossy vs Lossless Compression
Back in the days of dial up modems, loading websites took a very long time.
Internet speeds were slow, and it could take a minute or even longer to load webpages that required lots of images.
The bigger the size of the web page, the slower it was to load, and the less likely people were to stick it out and wait.
Nowadays, broadband (including fibre.
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Run-Length Encoding
RLE is a lossless compression technique that relies on the original piece of data having lots of repeating digits.
It is about finding repeating patterns of data in a file and encoding them to save space. ‘Runs’ of data (sequences of data having the same value) are stored using frequency/data pairs.
So if we had this image: The binary code for this.
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What is compression __?
Pages that contain large image files, or adverts can eat away at data limits quickly, and stop people being able to access the web pages they need.
This means that we need to find ways of saving data in such a way that it takes up less space than the original file.
This is called compression __. __ .
How does a compression algorithm work?
A compression algorithm is used to find and index repeated words or patterns (or sections of words) within the data
Wherever they occur in the data, the indexed words/patterns are replaced with numerical values
The index will need to be stored with the data to allow decompression with no loss of data
What is compression & how does it work?
Compression addresses these issues Any kind of data can be compressed
There are two main types of compression: lossy and lossless
Lossy compression removes some of a file’s original data in order to reduce the file size
This might mean reducing the numbers of colours in an image or reducing the number of samples in a sound file
What is data compression?
Data compression can be expressed as a decrease in the number of bits required to illustrate data
Compressing data can conserve storage capacity, accelerate file transfer, and minimise costs for hardware storage and network capacity
How Compression Works?
Back in the days of dial up modems, loading websites took a very long time. Internet speeds were slow,In computing, compression is the act of encoding a file to make it smaller in size. Compressed file types are essential for the online services we enjoy, such as streaming video and viewing websites. Compression can be categorised as either lossy or lossless.What is compression? To compress a file means to make its size smaller. Benefits of compression include: Files take up less storage space (so more files can be stored). Files can be transferred quicker (because they are smaller). Files can be read from or written to quicker.Compression is a technique that reduces file size. Some compression techniques are referred to as lossy, because they cause data to be lost during the compression process. Other techniques are referred to as lossless, because they allow the original data to be exactly reconstructed from the compressed data.Compression is executed by a program that uses a procedure to identify how to reduce the data size. Text compression can be done by eliminating unnecessary characters, embedding a repeat character to specify repeated characters, and substituting a smaller bit string for a commonly occurring bit string.A compression algorithm is used to find and index repeated words or patterns (or sections of words) within the data. Wherever they occur in the data, the indexed words/patterns are replaced with numerical values. The index will need to be stored with the data to allow decompression with no loss of data.
