Free online MK3D to TS converter

Devices and broadcast-style playback software often accept MPEG transport stream files but do not recognize the Matroska 3D container used by .mk3d. Converting the container can make the video usable for transmission, set-top playback, or editing, but it may not preserve Matroska-specific 3D metadata.

What the MK3D format is

MK3D is a filename extension for a Matroska video container designed for stereoscopic 3D. The underlying file structure is Matroska, like .mkv, with video, audio, subtitles, chapters, and stereo-layout metadata stored in one file.

You may encounter MK3D files ripped or authored with MakeMKV, assembled with MKVToolNix, or distributed as 3D video archives. The extension identifies the container and intended 3D use; it does not guarantee a particular video codec or stereo format. Common video streams include H.264, MVC, and HEVC, while audio may use AC-3, DTS, AAC, or other codecs.

What the TS format is

TS, or MPEG transport stream, is a packetized container used for digital television, Blu-ray-related workflows, broadcast delivery, and hardware playback. It handles transmission errors better than many file-oriented containers and supports multiple audio and video streams.

TS playback is commonly compatible with MPEG-2 video, H.264/AVC, HEVC, MPEG audio, AAC, and AC-3. Compatibility depends on the target device: a device may accept the TS container but reject a codec, subtitle type, frame rate, or 3D signaling method inside it.

How to actually convert MK3D to TS

Remux with FFmpeg when the codecs are compatible

Install FFmpeg, then inspect the source streams:

ffprobe -hide_banner input.mk3d

If the video and audio codecs are supported by the destination device, copy the streams without re-encoding:

ffmpeg -i input.mk3d -map 0:v:0 -map 0:a? -c copy -f mpegts output.ts

This is the fastest option and avoids generation loss. The -map 0:a? selector includes audio when present; it does not fail if the file has no audio. If the source contains subtitles or attachments, omit them unless the target specifically supports them, because MPEG-TS does not carry Matroska attachments and has limited subtitle compatibility.

For a file with several audio tracks, select the required one explicitly, for example:

ffmpeg -i input.mk3d -map 0:v:0 -map 0:a:0 -c copy -f mpegts output.ts

Transcode incompatible streams

If stream copying produces a file that the target cannot play, encode to widely supported formats such as H.264 video and AAC or AC-3 audio:

ffmpeg -i input.mk3d -map 0:v:0 -map 0:a:0 -c:v libx264 -preset medium -crf 18 -pix_fmt yuv420p -c:a aac -b:a 192k -f mpegts output.ts

Use a higher CRF value for a smaller file and a lower value for higher quality. For hardware or broadcast equipment requiring AC-3 instead of AAC, replace the audio options with -c:a ac3 -b:a 384k.

Use the website converter

You can convert the file for free on the 101convert.com website without installing software. Upload the MK3D file, select TS as the output format, start the conversion, and download the resulting file. Large files, private footage, unsupported 3D codecs, and browser upload limits can affect this method.

Quality, compatibility, and 3D limitations

Remuxing with -c copy does not reduce quality, but it also does not convert an unsupported codec. Transcoding decodes and re-encodes the video, so some quality loss is unavoidable.

MPEG-TS does not preserve all Matroska 3D flags, chapters, attachments, or subtitle features. If the MK3D file uses MVC or another stereoscopic format, the output may remain technically valid but appear as ordinary 2D video on a TS player that cannot interpret the 3D stream. A target requiring side-by-side or top-and-bottom 3D may need a separate video-layout conversion rather than simple container remuxing.

After conversion, verify the result with:

ffprobe -hide_banner output.ts

Test the file on the actual playback device, checking resolution, frame rate, audio format, subtitle behavior, and 3D presentation.