Xvid is just for video. If you have video but no sound, you likely need a separate audio codec, such as AC3 or MP3, which can be found in popular codec packs.
If you have a 4K monitor and a 100 GB library, re-encoding your files to Xvid would roughly quadruple their file size for no visual gain. Xvid is obsolete for high-definition or 4K archiving. Xvid Video Codec 2024
Xvid uses lossy compression, meaning it removes redundant visual data to drastically reduce video file sizes while attempting to maintain acceptable picture quality. During the era of DVDs, CD-Rs, and early file-sharing networks, Xvid was the global standard for ripping and distributing movies. A standard 4.7 GB DVD could be compressed into a highly watchable 700 MB file, fitting perfectly onto a single CD-R. Why are People Searching for Xvid Codec in 2024? Xvid is just for video
By the mid-2000s, Xvid became the gold standard for "scene releases." Its ability to compress a full-length DVD (4.7 GB) into a 700 MB CD-quality AVI file revolutionized peer-to-peer sharing. It offered better visual fidelity than DivX at the same bitrate, and it was free. Xvid is obsolete for high-definition or 4K archiving