Here is an overview of the formats (also called containers) and codecs that are used in CINELERRA-GG, by ffmpeg and the internal engine. Roughly speaking these are divided into uncompressed codecs (or codecs with Intraframe compression, which can be lossy or lossless) and compressed codecs of Interframe type (LongGOP, almost always with lossy compression). The All-I (intraframe) codecs are suitable for editing because a cut or other operation on the timeline corresponds to the exact frame on which you are operating. The interframe types use Groups of Pictures (GOP) and a cut or other operation is accurate (and requires no further calculation) only if it coincides with the beginning of the GOP, and not with an internal frame. There is also color compression: Color Space bit-depth and Chroma-Subsampling for YUV models. In addition, heavy compression requires the system to do more encoding/decoding work on the timeline. High quality codecs have high bit rates and bit depths but this also affects the performance of the system, not to mention the increased disk space usage. Some formats implement both audio and video streams, others audio only or video only.