Decompression is the process of reversing the compression applied to data in order to restore it to its original state. When data is compressed using various compression algorithms, its size is reduced by removing redundancies, repetitions, or less important information. Decompression involves applying the reverse operations to the compressed data to recreate the original data, ensuring that no essential information is lost during the process.
The key steps involved in decompression include:
Decompression Algorithm Selection:
- Depending on the compression method used, the appropriate decompression algorithm is chosen.
- Each compression algorithm has a corresponding decompression algorithm designed to reverse the compression process and restore the original data.
Reverse Transformations:
- In lossless compression, the data is restored by reversing the transformations applied during the compression process.
- For example, in Huffman coding, the coded bitstream is decoded back into the original sequence of symbols using the Huffman tree.
Reconstruction of Data Structures:
- If the compression algorithm involved rearranging or restructuring the data, the decompression process restores the original structure.
- For instance, in dictionary-based compression like LZ77/LZ78, the decompressor reconstructs the dictionary to recreate the original data.
Lossy Decompression (if applicable):
- In some cases of lossy compression, where non-essential information was discarded, the decompression process attempts to recreate the data as closely as possible to the original while acknowledging the loss of some details.
- Lossy compression techniques are commonly used in multimedia formats like images and audio, where minor loss of quality may not be noticeable.
Verification and Validation:
- After decompression, validation checks are performed to ensure the integrity of the restored data.
- Some compression algorithms include checksums or error-checking codes to verify that the decompressed data matches the original data.
Decompression is an essential part of many applications, including data transmission, file archiving, multimedia streaming, and more. It ensures that compressed data can be effectively restored to its original form when needed, without any loss of information. The efficiency and accuracy of decompression algorithms play a crucial role in maintaining the quality and integrity of data after compression.