Old formats still hold useful video
AVI, WMV, FLV, 3GP, MPG, OGV, and TS files may contain perfectly usable clips, but modern platforms often prefer MP4.
Why MP4 is the target
MP4 is widely accepted by phones, browsers, social platforms, editors, and upload forms. It is the practical compatibility format.
Check the archive
After conversion, compare duration and audio. Old files can have unusual codecs or damaged sections.