Free online KUX to OGV converter

What the KUX format is

KUX is a proprietary video format associated primarily with Youku downloads and the Youku desktop application. It is used to store locally downloaded or cached video, often with Youku-specific metadata, segmentation, or protection.

KUX files commonly appear after downloading videos through Youku software rather than receiving a standard MP4 file. Support varies by KUX version, so a file that plays in the Youku application may fail in VLC, FFmpeg, or a video editor.

What the OGV format is

OGV is an Ogg video file, usually containing Theora video and Vorbis or Opus audio. It is supported by many open-source media players, web tools, and Linux applications.

OGV is useful when an application specifically requests an Ogg-based video or when you need a format with open specifications. It is usually less efficient than H.264 or VP9, so an OGV file may be larger than an equivalent modern MP4 at similar visual quality.

How to convert KUX to OGV

Using the built-in online converter

1. Open the KUX-to-OGV converter on 101convert.com.
2. Choose the KUX file from your device.
3. Set the output format to OGV and start the conversion.
4. Download the generated .ogv file and test it in the target application.

This method requires no software installation. Uploading can be impractical for very large files, and protected or damaged KUX files may be rejected. Do not upload material that cannot legally or safely be transferred to a third-party processing service.

Using FFmpeg after obtaining a standard source file

FFmpeg generally does not decode every proprietary KUX variant directly. If the Youku application provides an MP4 or another standard export, use that file as the input rather than renaming the KUX extension.

Install FFmpeg, open a terminal in the folder containing the source video, and run:

ffmpeg -i input.mp4 -c:v libtheora -q:v 7 -c:a libvorbis -q:a 5 output.ogv

The -q:v value controls Theora quality; higher values generally produce better quality and larger files. The -q:a value controls Vorbis audio quality. For a video with no audio track, use:

ffmpeg -i input.mp4 -an -c:v libtheora -q:v 7 output.ogv

If FFmpeg reports that the input format is unsupported, first use a KUX-capable Youku application or converter to export a playable standard-format file. Changing .kux to .mp4 does not convert the data.

Quality and compatibility limitations

Conversion cannot restore detail that was removed during the original Youku encoding. A KUX-to-OGV conversion normally decodes the source and re-encodes it with Theora, so it can reduce quality and may change frame rate, subtitles, metadata, or multiple audio tracks.

Check the result with an OGV-compatible player after conversion. If the source is DRM-protected, encrypted, incomplete, or restricted by the provider, a converter may be unable to process it; bypassing access controls may also violate the provider’s terms or copyright law.