Downloading a standalone for Android is not possible because Android manages video decoding through individual media player apps rather than system-wide codec packs. Instead of a separate codec download, you should use a media player that includes built-in Xvid support . Recommended Apps for Xvid Playback
: Known for hardware-accelerated playback and excellent subtitle support.
: Subtitle support, gesture controls, and hardware acceleration. 2. MX Player
If you want to play the file on the stock Android gallery or simply want better battery efficiency, converting the video to a modern format is a better long-term solution. Video Converter Android