Mkvtoolnix how to Combine Files
MKVToolNix lets you merge multiple video files into a single MKV container without re-encoding—a process called remuxing. The tool handles the core task through its GUI or command-line interface, making mkvtoolnix how to combine files straightforward whether you're working with MKV, WebM, or other supported formats on Windows 10, Windows 11, or Linux Ubuntu.
Understanding MKV Merging Basics
File combination with this software requires understanding that merging differs from encoding. No quality loss occurs because the video streams, audio tracks, and subtitle data remain untouched—only their container changes. This is why remuxing is fast and ideal for organizing multi-part episodes or consolidating source files.
The software works as an MKV editor free and open-source solution. It manages track selection, metadata editing, and chapter information without proprietary restrictions. Version 91.0.0 supports 64-bit systems on both Windows and Linux platforms, with 32-bit builds available for legacy installations.
Using the GUI to Merge Video Files
Open the mkvtoolnix GUI application. The interface displays a file selector on the left—drag or add your first video file here. The right panel shows all tracks: video streams, audio tracks (H.264, H.265, HEVC codecs supported), and subtitle files in SRT or ASS formats.
Add subsequent files by clicking the "Add source files" button or dragging them into the track list. Each file's tracks appear as separate rows. You control whether each track merges into the output: check the box next to tracks you want included, uncheck those you don't.
The output filename defaults to the first source file's name—change it at the top. Hit "Start muxing" and the tool combines everything into a single MKV container. Processing time varies with file size but typically completes in seconds.
Advanced Options for File Merging
The "Format" tab contains crucial settings. Default language assignment matters if your audio tracks lack metadata. The "Subtitles" section lets you embed or extract SRT subtitles before merging, useful when combining files with separate subtitle files.
Chapters warrant attention. If source files contain chapter information, the merge tool preserves existing chapters. The "Edit chapters" feature appears under the Chapters tab—here you rename segments, adjust timestamps, and set default chapters for the merged output.
An MKV merge tool also handles audio track manipulation: reorder tracks, set default audio streams, or remove redundant audio versions. This prevents accidentally playing the wrong language version after combining files.
Command-Line Approach
For batch operations, the command-line interface processes multiple jobs automatically. The syntax follows: `mkvmerge -o output.mkv input1.mkv +input2.mkv`. The `+` prefix tells the application to continue appending tracks from the next file.
This method scales for converting containers across dozens of files. Linux users especially benefit from scripting merge operations—combine file globbing with mkvmerge to process entire directories in one command.
Comparing Alternatives
Unlike File Converter as a cross-format option, this tool specializes exclusively in Matroska and WebM containers. Fre:ac focuses on audio conversion rather than video merging, making it unsuitable for combining video files. For video-only needs, this remains the dedicated free choice.
Learn more about the graphical interface with the MKVToolNix GUI workflow guide.
Final Steps for Video File Combination
After merging completes, verify the output plays correctly and contains all intended tracks. The resulting MKV file maintains compatibility with most modern media players—test on your target playback device if critical.
No ads, no watermarks, and no licensing limits apply. Open-source development means continuous updates and transparent code. Download from the official repository to ensure you receive the legitimate version without bundled software.