How to Combine MP4 Files Into One

Rather than playing multiple MP4 files that make up an entire video, use free applications such as MP4Joiner, AVIDemux or Freemake Video Converter to combine them seamlessly into a single MP4 file. MP4Joiner and AVIDemux allow you to rapidly combine MP4 files of similar resolutions without the need to re-encode them, while Freemake Video Converter allows you to combine MP4 files consisting of similar or differing resolutions by re-encoding them at either high-definition or standard-definition resolutions.

Download and install MP4Joiner from MP4Joiner.org (link in Resources). After installing, open MP4Joiner.

Use the “Add Video” button to select MP4 files on your hard drive. To select multiple MP4 files within the same directory, hold down “Ctrl” as you click each file. MP4Joiner cannot rearrange videos after you select them, so select files in the order that you want to combine them.

Click “Join.” Insert a filename, select an output location, and then click “Save.” A pop-up box displays a progress bar and the estimated time required to complete the combining process.

Download and install AVIDemux 32-bit for Windows 32-bit or AVIDemux 64-bit for Windows 64-bit from the AVIDemux Downloads page on SourceForge.net (link in Resources). After installing, open AVIDemux.

Click “Open” to select the first MP4 file in the series that you need to combine. Click “File,” and then click “Append” to select the second MP4 file. Use the Append function to select any additional MP4 files in the order that you need to combine them.

Click the pull-down menu under "Audio Output," select "Copy." Click the pull-down menu under "Video Output," and then select "Copy." Click the pull-down menu under "Output Format," and then select “MP4 Muxer.”

Click the “Save” button. Insert a filename, select an output location, and then click “Save” to combine the MP4 files. If AVIDemux fails to combine your MP4 files, select “MP4v2 Muxer” instead of "MP4 Muxer" under "Output Format," and then try again.

Download and install Freemake Video Converter from Freemake.com (link in Resources). After installing, open Freemake Video Converter.

Use the “Video” button to select the MP4 files in the order that you need to combine.

Click the button next to “Join Files,” and then click the “To MP4" button to get to the re-encoding screen.

Use the pull-down menu under “Preset” to select either “HD 720p,” “HD 1080p” or “DVD Quality” (SD quality). Both HD 720p and HD 1080p are high-definition output standards, where the former takes less file space at reduced visual quality. DVD Quality outputs a standard resolution MP4 file that is visually inferior to both HD 720p and HD 1080p, but takes up a very low amount of disk space.

Use the browse button under Save To to set an output destination and filename.

Toggle between “One-Pass Encoding” or “Two-Pass Encoding.” The former results in a larger file size but takes less time to complete, while the latter results in a smaller file but takes more time to complete. For example, Freemake Video Converter may take around 10 minutes to re-encode MP4 files with a combined runtime of 60 minutes at HD 720p output using one-pass encoding.

Click “Convert” to combine the MP4 files.