Free online KUX to MPEG converter

You may need this conversion when a television, editor, disc-authoring application, or older media player accepts MPEG but cannot open a Youku download. Converting also replaces the proprietary KUX container with a format supported by more desktop video software.

What the KUX format is

KUX is a proprietary video container associated mainly with videos downloaded from Youku using its desktop or mobile software. You usually encounter .kux files in a Youku download folder rather than as camera or editing exports.

The container can hold video and audio streams in a Youku-specific layout, and some downloads use segmentation or protection that prevents general-purpose players from reading them. A KUX file is therefore not simply an MPEG file with a different extension; renaming video.kux to video.mpg does not convert it.

What the MPEG format is

MPEG is a family of standards rather than one single codec. For a conventional .mpg or .mpeg output, the usual target is an MPEG program stream containing MPEG-2 video and MP2 audio.

MPEG-2 program streams are supported by many older televisions, set-top boxes, DVD-related tools, broadcast workflows, and legacy media players. The format is less efficient than modern H.264 or H.265, so an MPEG conversion can produce a larger file without improving the source picture.

How to convert KUX to MPEG

Using the built-in online converter

You can convert the file for free on the 101convert.com website without installing software. Select the KUX-to-MPEG conversion, upload the KUX file, start the conversion, and download the resulting .mpg file. The service can only process a file that is readable by its converter; protected or incomplete Youku downloads may fail.

Using FFmpeg on a desktop

FFmpeg is useful when it can decode the particular KUX file. First test the input:

ffmpeg -i input.kux

If FFmpeg identifies the video and audio streams, create a broadly compatible MPEG-2 program stream with:

ffmpeg -i input.kux -map 0:v:0 -map 0:a? -c:v mpeg2video -b:v 5M -c:a mp2 -b:a 192k -ar 48000 output.mpg

Replace input.kux with the actual filename. Increase or decrease -b:v 5M to control picture quality and file size; the command deliberately transcodes because KUX content is commonly encoded with codecs that do not belong in a conventional MPEG-2 program stream.

If the source streams are already compatible and FFmpeg reports no container or codec conflict, a remux may avoid quality loss:

ffmpeg -i input.kux -map 0 -c copy -f mpeg output.mpg

Use the transcode command when remuxing produces an error, a file with no sound, or a file that the target device cannot play. On Windows, run these commands in PowerShell or Command Prompt from the folder containing ffmpeg.exe; on macOS or Linux, install FFmpeg through the operating system’s package system.

Quality and compatibility limitations

Transcoding KUX to MPEG-2 is lossy when the source uses H.264 or another compressed codec. Keep the original KUX file if it is still playable, and avoid repeated conversions.

Some KUX files are encrypted, incomplete, or split into download segments. FFmpeg cannot decode such files unless it has support for the specific protection scheme; changing the extension will not remove protection. Re-download the video through the authorized Youku software or use a converter that explicitly supports that KUX variant.

For DVD-oriented hardware, use the television standard required by the device: NTSC commonly uses 720×480 at approximately 29.97 frames per second, while PAL commonly uses 720×576 at 25 frames per second. A generic MPEG file may play correctly on a computer but fail on a strict DVD player if its resolution, frame rate, audio format, or bitrate is outside the player’s requirements.