Merge Multiple Video Files With VirtualDub

Mark O'Neill 05-09-2008

Merge Multiple Video Files With VirtualDub videoreelMy mother and I have a tradition. Every year, she sends me a DVD recording of the Edinburgh Military Tattoo which is shown on BBC television every August. I have quite a few years worth of Tattoo recordings now – mostly Scottish bagpipe music so when I get a bit homesick, I turn it on, crank up the volume and start dancing round the room!


The other day I decided to merge some of the “avi” video files into one big “avi” file so they can be played continuously. Video file merging can be done easily and quickly with a piece of free open source software called VirtualDub.

VirtualDub is the video equivalent of Audacity Record audio files with Audacity Read More . You can use it to edit your video files any way you want them – you can merge the video files, split them, save the source audio, capture screenshots, fix the colouring in the video footage and much more.

combine video clips together

It’s worth taking some time to explore VirtualDub in depth if you’re serious about video footage editing. I use VirtualDub, for example, to edit my videos after filming on my video camera. Today I am going to show you how to merge two or more video files together. Next time I will show you how to split video files (also see how to split regular files to pieces) into separate files which is also an extremely handy skill to practice.

Please note that the video files in question HAVE to be “avi” files.


When you have opened VirtualDub, go to File–>Open Video File.

merge video files

Now upload the first “avi” file you want to have in your new video file.

Next, go to File–>Append AVI segment :



Now upload the second “avi” file you want to have in your new video file.

If you have more than 2 files, continue to return to File–>Append AVI segment and attach as many files as you want. Watch the size of the new file though! Don’t let it get too big!

When you have attached all the files together into one big new file,the next step is to go to Video–>Direct Stream Copy. If you don’t choose this option and go for the default “Full Processing Mode”, you’ll be waiting for ever for your new file to be made. A DSC on the other hand will be made for you in less than 60 seconds (often a lot less) :


combine video files into 1

Finally, go to File–>Save Segmented AVI to save your work to your computer :

combine video files

Put in a new name for your new combined file and then VirtualDub will get to work, merging all the files into one big one for you.


Once it’s finished, test it and you’ll see that the merging was so good, you don’t even see any disturbance in the picture where one file ended and another began! There will be the odd occasion though when the sound may get out of sync a little but some advanced users may be able to quickly fix that problem. I am not knowledgable enough to be able to fix sound synchronisation problems.

VirtualDub is an amazing piece of free software. Along with Audacity, you have all you need to edit and put together video and audio on your computer – without any of it costing you a single penny. I highly recommend you download this app to your computer and take the time to go through it.

What other pieces of video editing software do you like to use? Anything that gives VirtualDub a run for its money?

Explore more about: Online Video, Video Editor.

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  1. Ikki
    January 8, 2017 at 1:28 am

    Thank you soooo much! I love how this website can help me with so many stuff.
    Keep up the great work! :)

  2. yeah
    March 8, 2016 at 3:14 pm

    Only took a minute to merge together two hours of videos. Thank you.

    • Mark O'Neill
      March 8, 2016 at 3:33 pm

      You're welcome. I'm glad the guide was easy to follow :-)

  3. Keiran
    January 18, 2015 at 10:14 pm

    Thanks for this simple and easy guide.

    Found your site via Google - it has the right answer for my simple question - easiest thanks to your screenshots.

  4. ad
    July 15, 2009 at 1:37 pm

    thank you, very helpful indeed!

  5. Ibrahim
    July 10, 2009 at 6:16 pm

    @Timo - Use Format Factory - - to merge and split all kinds of files including FLV files.

  6. Sam
    June 27, 2009 at 1:07 pm


  7. Timo
    June 11, 2009 at 5:54 am

    Could this (merge multiple files) functionality be extented to cover Windows Media Files (.wmv)? If not with Virtualdub, what FREE alternatives there are for joining multiple .wmv files (in direct stream copy mode)?

    May 21, 2009 at 8:38 pm

    anyone know how to fix the problem with vdub after merging the video the audio is not in sync with the mouth??? thanks

  9. Shreela
    September 5, 2008 at 11:29 pm

    I knew how to apend with vdub, but didn't know the rest, and it did take FOREVER! Using your technique, I combined two large AVI's really fast, wooo thanks!

  10. Gary
    September 6, 2008 at 2:10 am

    I love VirtualDub too. A great little tool. However there are quite a few other free tools out there that might be worth looking at:

    T@B ZS4
    Video Spin

    A lot of those work on the Mac too, as does Hyperengine-AV.

    Granted a lot of these are focused slightly differently to VirtualDub but that's why V-Dub is such a unique tool!

    Remember though, with video editing tools the skill is not necessarily in choosing the right tool, but in knowing how best to use that tool to give you the effect you need

    Thanks for the post


    • Aibek
      September 8, 2008 at 4:27 pm

      Nice, I had no idea there were so many free video editors out there, thanks for sharing, Appreciated!

  11. Cami
    September 5, 2008 at 1:18 pm

    Something like this for Mac OS? A direct-stream-copy mode. Tried avidemux to no avail, also quicktime, but the outpout is not an xvid file. Thank you!

  12. Zia
    September 5, 2008 at 4:43 pm

    I'd rather stick with Kate's video Joiner... Supports AVI, WMV, MOV , DIVX, ASF, 3GP, MP4, MPEG1, MPEG2, VCD-PAL ,VCD-NTSC, SVCD-PAL, SVCD-NTSC, DVD-PAL, DVD-NTSC, and other formats...Fast and extremely easy to use!

    • Aibek
      September 8, 2008 at 4:23 pm

      Thanks, for heads up, it's always good to have an alternative.

    • raj
      January 9, 2009 at 6:23 am

      I used Kate for merging 5 avi files of 899k each; it took 9 hours on my new pc!!