Free online TAR.GZ to MKV converter

A TAR.GZ file is an archive, while MKV is a video container, so this task usually means extracting video from the archive and then packaging or encoding it as MKV. If the archive already contains an MKV file, extraction is all that is required; otherwise, use a media tool such as FFmpeg on the extracted video.

What the TAR.GZ format is

TAR.GZ combines a TAR archive, which stores files without compression, with GZIP compression. It is commonly created by GNU tar, BSD tar, Linux backup tools, Unix software distribution systems, and 7-Zip. You may encounter it when downloading source packages, backups, media collections, or files exported from Linux and macOS systems.

The archive can contain any file type, including MP4, AVI, MOV, or MKV video. The .tar.gz extension does not identify the contents as video and cannot be converted directly into a video stream.

What the MKV format is

MKV, or Matroska Video, is a multimedia container that can hold video, multiple audio tracks, subtitles, chapters, metadata, and attachments. It is useful for preserving several language tracks and subtitle formats in one file, and it supports codecs such as H.264, H.265/HEVC, AV1, AAC, and Opus.

MKV is widely supported by VLC, Kodi, mpv, Plex, and modern desktop operating systems, but some televisions, mobile devices, and editing applications support MP4 more reliably. MKV is appropriate when you need a flexible container or want to retain multiple tracks without immediately re-encoding them.

How to actually convert TAR.GZ to MKV

1. Inspect and extract the archive

On Linux or macOS, list the contents before extracting:

tar -tzf archive.tar.gz

Extract everything into a separate directory:

mkdir extracted && tar -xzf archive.tar.gz -C extracted

On Windows, open the file with 7-Zip and choose Extract Here or Extract to archive\. If the result is a separate .tar file, extract that file as well; GZIP compression and TAR archiving are two layers.

2. Check whether an MKV already exists

If extraction produces video.mkv, no conversion is necessary. Move or rename the file if required. If it produces another video format, continue with FFmpeg.

3. Remux without quality loss when possible

FFmpeg can copy compatible audio and video streams into an MKV container without re-encoding:

ffmpeg -i extracted/video.mp4 -map 0 -c copy output.mkv

The -map 0 option retains all streams that FFmpeg can read, including additional audio and subtitle tracks. Stream copying is fast and does not reduce quality, but it can fail if the source contains damaged data or an unusual stream that MKV cannot contain.

4. Re-encode when the source is incompatible

Use H.264 video and AAC audio for broad compatibility:

ffmpeg -i extracted/video.avi -map 0:v:0 -map 0:a? -c:v libx264 -crf 20 -preset medium -c:a aac -b:a 192k output.mkv

Lower CRF values generally increase quality and file size; values around 18–23 are common for H.264. Re-encoding takes substantially longer and can reduce quality, so try stream copying first.

5. Process several extracted videos

Run FFmpeg separately for each source file, because an archive may contain multiple unrelated videos. For a shell loop covering common MP4 files:

for f in extracted/*.mp4; do ffmpeg -i "$f" -map 0 -c copy "${f%.mp4}.mkv"; done

For a no-installation option, you can use the free converter on 101convert.com. Extract the TAR.GZ first if the site does not accept archives, then upload the contained video and select MKV.

Quality, compatibility, and limitations

GZIP compression affects the archive, not the audio or video quality. Extracting the archive does not alter the media; only re-encoding changes quality.

MKV is a container rather than a codec. Changing MP4 or AVI to MKV with -c copy changes the container while preserving the encoded streams. A device that rejects MKV may also reject a codec inside it, so re-encoding the video and audio may be required even after successful remuxing.

Check the output with ffprobe output.mkv or a media player, especially when the archive contains subtitles, chapters, multiple audio tracks, or files with non-ASCII names.