Data Compression Flashcards
What is data compression?
The techniques revolutionizes how you manage, store, and transmit digital information. It is a technique for minimizing the size of data files, enabling more efficient storage and faster transmission. This method is crucial across various industries and applications from the Internet to multimedia production, enhancing the efficiency of data management and communication.
What is lossless data compression?
It allows for the original data to be perfectly reconstructed from the compressed data. This method is essential for applications, where the exact reproduction of the original data is critical such as text documents,
software applications, and certain types of media files. Losslesscompression works by eliminating
redundancy without sacrificing any nformation. Common algorithms and techniques used in
lossless compression include run-length encoding or RLE. This technique compresses data by replacing sequences of repeated characters with a single character and account of its repetitions.
What is Huffman coding?
A method that assigns shorter codes to more frequent characters and longer codes to less frequent ones. Huffman coding is widely used due to its simplicity and effectiveness. Lempel-Ziv-Welch or LZW. This algorithm builds a dictionary of sequences encountered in the data, replacing these sequences with shorter references to the dictionary. LZW is the basis for many file compression formats, including GIF and TIF.
What are lossy techniques?
Allows for some loss of information, trading data fidelity for a higher compression ratio.
This approach is suitable for applications, where a perfect reproduction of the original data is not
necessary such as in audio, video, and images. By removing parts of the data that are less important to human perception, significant reductions in file size can be achieved.
Popular lossy compression techniques include JPEG, which is short for joint photographic experts group. JPEG is a common format for compressing photographic images. It uses the discrete cosine transform or DCT to reduce the file size by
discarding less perceptible information.
Next is MP3 or MPEG audio layer 3, widely used for audio compression. MP3 compresses sound files by removing frequencies that are less audible to human ears, effectively reducing the file size while maintaining acceptable sound quality.
Another lossy compression technique is MPEG or motion picture experts group, a standard for video compression. It achieves high compression ratios by only storing changes between consecutive frames and reducing color resolution among other techniques.
Lossy compression is invaluable in multimedia applications where it enables the storage and streaming of high quality audio and video with significantly reduced data sizes.
