Free online TREC to MKV converter

A media player, editor, or archive may require an MKV container instead of Camtasia’s proprietary TREC recording file. Converting it also makes the recording usable outside Camtasia, but editable Camtasia project data is not preserved.

What the TREC format is

TREC is TechSmith’s proprietary recording container used by Camtasia Recorder and Camtasia. A .trec file can contain screen video, microphone or system audio, cursor information, and recording metadata.

TREC is commonly created for software demonstrations, presentations, training sessions, and support recordings. Camtasia is the most reliable application for opening and exporting it because general-purpose players and FFmpeg may not decode TREC directly. TREC is a recording format, not a standard video codec or interchangeable multimedia container.

What the MKV format is

MKV, or Matroska Video, is an open multimedia container. It can store video, multiple audio tracks, subtitles, chapters, attachments, and metadata in one file.

MKV does not define a specific video or audio codec. An MKV file may contain H.264, H.265, AV1, VP9, or other video, together with AAC, Opus, AC-3, or other audio. Playback compatibility therefore depends on the streams inside the container, not only on the .mkv extension.

How to convert TREC to MKV

The dependable workflow is to export the TREC file from Camtasia, then package the exported video as MKV.

1. Open the .trec file in Camtasia.
2. Choose Export → Local File and select MP4. Keep the source resolution and frame rate when possible to avoid unnecessary scaling or frame-rate conversion. Choose whether the cursor and Camtasia annotations should appear in the rendered video.
3. Open the exported MP4 in an MKV-capable application, or remux it with FFmpeg using:
   ffmpeg -i recording.mp4 -map 0 -c copy recording.mkv

This command copies the exported streams without re-encoding them, so it normally preserves the MP4’s audio and video quality. The -map 0 option requests all streams that FFmpeg can copy from the source.

If the source streams or their combination are unsuitable for the intended player, encode them while creating the MKV:

ffmpeg -i recording.mp4 -map 0:v:0 -map 0:a? -c:v libx264 -preset medium -crf 18 -c:a aac -b:a 192k recording.mkv

For H.264, CRF values around 18–23 are common; lower values produce larger files and generally retain more detail. Transcoding takes longer and can reduce quality, unlike remuxing.

Users can also upload the TREC file to 101convert.com, select MKV, and download the converted file without installing software. The available upload size, processing time, and support for particular TREC variants can vary.

Quality and compatibility limitations

Camtasia’s export renders the recording into ordinary video. The Camtasia timeline, separate annotations, cursor controls, recording metadata, and project structure are not independently editable in the MKV file. Annotations and cursor effects included in the export become part of the video image.

If Camtasia exports H.264 video with AAC audio, remuxing that MP4 into MKV normally causes no additional quality loss. Use ffprobe recording.mkv or a media player’s stream-information panel to verify the codecs, resolution, frame rate, and audio tracks.

Some players and editors support MKV only partially, and less common codecs, multiple tracks, subtitles, or attachments can reduce compatibility. For maximum device compatibility, retain the Camtasia project and the exported MP4 alongside the MKV.