Converting Old AVI/WMV/FLV Videos to MP4: A Guide to Making Legacy Videos Playable

AVI is a video container format released by Microsoft in 1992. It originated in the Windows 3.1 era, was once the default general video format for Windows systems, and was widely used in early recording devices.

WMV is a proprietary video encoding container launched by Microsoft, developed based on the Windows multimedia framework. It was once mainly used for system built-in players and network streaming media transmission, and was one of the mainstream formats in the early PC ecosystem.

FLV is a streaming media container that developed along with Flash Player technology. It was the mainstream web video format from 2000 to 2015, and most early online courseware and short videos were stored in FLV format.

Legacy videos have the problem of both outdated encoding and outdated container. Most AVI files encapsulate old encodings such as MPEG-4 and DivX, WMV relies on Windows' proprietary encoding framework, and the VP6 and Sorenson Spark encodings encapsulated in FLV have all stopped maintenance.

To reduce file size, modern mobile phones, smart TVs and mainstream players only integrate current mainstream encodings such as H.264 and H.265 by default, and will not preload obsolete old encoding components. Therefore, they cannot normally decode and play these videos.

AVI files generated by some old recording devices have non-standard encapsulation issues that do not conform to modern container parsing rules. Even if the player is compatible with old encodings, it may still fail to load the file.

Converting legacy videos to MP4 format encapsulated with H.264 video encoding and AAC audio encoding can cover almost all modern playback devices and solve the problem of unplayable videos.

We have summarized the compatibility differences of three common output configurations as follows:

Some users need to make dynamic memes from old surveillance clips or dashcam highlight clips. They can convert specified clips to GIF format for sharing on social platforms. OKfmt's video to GIF converter supports custom clip ranges.

For course audio stored in FLV format, users can extract the audio and output it as MP3 format, store it in a mobile phone music player to listen to anytime anywhere, without retaining the video screen, which saves storage space.

Besides AVI, WMV and FLV, other common legacy video formats include 3GP from the feature phone era, VOB extracted from DVD discs, and MPG extracted from VCD discs. These formats can also be uniformly converted to H.264+AAC MP4 to solve compatibility issues.