"WEBRip.x264-GalaxyRG" indicates a video captured from a streaming source (WEBRip), encoded with the x264 codec, and released by the GalaxyRG group. While offering good compatibility, WEBRips generally offer lower quality than WEB-DLs and use a less efficient codec than x265. For more on these terms, visit Reddit WEB-DL & WEBrip Quality Profiles Should Be Separated
