Free online KUX to MOV converter

A video downloaded from Youku may be saved as a .kux file that common editors, phones, and Apple applications cannot open. Converting it to .mov produces a QuickTime-compatible file for editing, playback, or archiving, provided the KUX file is not protected by DRM.

What the KUX format is

KUX is a proprietary video container used by Youku and its download software for offline video files. You usually encounter it after downloading content through a Youku desktop or mobile application rather than receiving it as a standard MP4 file.

A KUX file may contain proprietary metadata, a nonstandard stream layout, or encryption and usage restrictions. Renaming video.kux to video.mov does not convert the video and will not make an incompatible or protected file playable.

What the MOV format is

MOV is the QuickTime container developed by Apple. It can store video, audio, subtitles, timecode, and metadata using codecs such as H.264, HEVC, ProRes, and AAC.

MOV is commonly accepted by QuickTime Player, Final Cut Pro, Adobe Premiere Pro, DaVinci Resolve, and other editing applications. Compatibility depends on the codecs inside the container; a MOV file is not automatically editable just because its extension is .mov.

How to actually convert KUX to MOV

Use the online converter

1. Open the KUX conversion page on 101convert.com.
2. Select or upload the original .kux file.
3. Choose MOV as the output format and start the conversion.
4. Download the resulting .mov file and test it in the intended player or editor.

This option requires no software installation and is available free of charge. Upload only videos that you are permitted to process, especially when the file came from a subscription or offline-download feature.

Use FFmpeg when the file is actually readable

FFmpeg can convert a KUX file only when its installed build recognizes the contained streams and the file is not encrypted. A direct transcode attempt is:

ffmpeg -i input.kux -c:v libx264 -c:a aac -movflags +faststart output.mov

If FFmpeg reports an unknown format, invalid data, or an unsupported stream, changing command options will not bypass Youku encryption. Obtain an officially exported or otherwise playable source first, then convert that source:

ffmpeg -i input.mp4 -c:v libx264 -c:a aac -movflags +faststart output.mov

Use -c copy only when the source codecs are accepted by the target workflow; otherwise the streams must be re-encoded as in the commands above.

Quality and compatibility limitations

Transcoding cannot restore detail already lost in the KUX source. Keep the original resolution and frame rate unless the destination requires different settings, and expect some quality loss when using H.264 or another lossy codec.

A successful conversion may still produce a MOV that an editor rejects because of its codec, profile, audio format, variable frame rate, or DRM restrictions. H.264 video with AAC audio is broadly compatible; ProRes is preferable for editing but creates much larger files. Protected or incomplete Youku downloads may not be convertible at all.