Recompressed

Recompressed refers to data that has undergone a second or subsequent stage of compression after an initial encoding. This is common with media files such as audio, video, and imagery, but can apply to any digitally encoded data. Recompression may occur when content is redistributed in a different format, needs to meet new bandwidth or storage constraints, or must be adapted to a particular playback platform. The process is a form of transcoding or re-encoding, typically involving a conversion to a different codec, container, or bitrate.

In lossy compression, recompression is usually associated with quality loss because each encoding stage discards information. Artifacts such as blurring, blocking, or ringing can accumulate, and the final file may be of lower perceptual quality than the original. Recompression of lossless formats can be lossless if the second encoding preserves all data and uses a lossless codec; otherwise, it remains lossy.

Reasons to recompress include compatibility with devices, streaming services, or media libraries; reducing file sizes for storage; or embedding in a standardized container. Efficient recompression strategies attempt to minimize quality loss by optimizing bitrate, using higher-quality settings, or recreating the source from a higher-quality intermediate if available.

In practice, recompression is often assessed by bitrate, encoding parameters, and subjective quality. It is distinct from simple copying, which preserves the original data without encoding changes.