Data Compression Practice Test
•14 QuestionsRead the passage. In a streaming-service setting, data compression reduces the number of bits needed to store or transmit information. Compression works by finding patterns and representing them more efficiently, which helps platforms deliver movies, music, and captions quickly over limited bandwidth. Two broad categories appear: lossless compression preserves every original detail so the decompressed data matches exactly, while lossy compression removes some information to achieve smaller files. For text such as subtitles and chat logs, lossless methods are common because even a small change can alter meaning; Huffman coding assigns shorter bit patterns to frequent symbols, and LZW replaces repeated sequences with short codes. For images and video, lossy methods often dominate because the human eye tolerates small changes; JPEG compresses still images by discarding subtle visual details, and MPEG compresses video by combining spatial compression with frame-to-frame prediction. The trade-off is constant: stronger compression usually means smaller files but more noticeable artifacts, so services adjust settings to balance quality and smooth playback.
Based on the text, what trade-offs are involved in using JPEG compression?
Read the passage. In a streaming-service setting, data compression reduces the number of bits needed to store or transmit information. Compression works by finding patterns and representing them more efficiently, which helps platforms deliver movies, music, and captions quickly over limited bandwidth. Two broad categories appear: lossless compression preserves every original detail so the decompressed data matches exactly, while lossy compression removes some information to achieve smaller files. For text such as subtitles and chat logs, lossless methods are common because even a small change can alter meaning; Huffman coding assigns shorter bit patterns to frequent symbols, and LZW replaces repeated sequences with short codes. For images and video, lossy methods often dominate because the human eye tolerates small changes; JPEG compresses still images by discarding subtle visual details, and MPEG compresses video by combining spatial compression with frame-to-frame prediction. The trade-off is constant: stronger compression usually means smaller files but more noticeable artifacts, so services adjust settings to balance quality and smooth playback.
Based on the text, what trade-offs are involved in using JPEG compression?