FrapsJoin - quickly joins AVI segments


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I've written a small script (an expanded mod of a contribution of user koala85) that joins Fraps 4GB videos quickly and easily. It works by renaming videos with serial numbers*. It processes a whole folder at once. It's got some other neat features:
  • you can set a meaningful name for each group of files ("take1", "replay" etc)
  • you can generate scripts for Avidemux, Avisynth and Virtualdub.
  • a BAT file is generated which restores the original names (in case you don't like
    the new names, it's easy to go back).
Here's the link: for the "ZIP" button).
(last updated Jan 27)
* if you want to joint the files directly without opening another program, see

Tutorial: Renaming the Files

One way to launch it is with "Send To" (send any file in the folder)

For each "group of videos" (that is, each continuous recording), you will see this:
"Enter name for this group of videos, or hit Enter to accept the default:"

NOTE any files not part of a group will not be renamed (they are usually
false starts anyway; check each file and rename or delete it)

Merging the Files

Now the files are much easier to manage. What you do next depends on how
you work. If you normally bring your Fraps files directly into a video editor, you can
still do that; it will be a little easier now that you have meaningful file names.

If you normally transcode before bringing the files into your editor, or if you don't
use an editor and just encode directly to your finished movie, the best way to merge
the files is with VirtualDub. V-Dub can merge all files in a group in 2 easy steps:
  1. open the first file of the group. It will be named "<something>-000.avi"
  2. open the next file with Append AVI Segment & Autodetect enabled, like so:
You can now trim, crop, resize, color-correct and save to AVI with VirtualDub.

If you prefer another encoder, such as StaxRip or WinFF, the best way to go is
with an Avisynth script. FrapsJoin can automatically generate it for you. Review
the README and INI file included with the project. If it's not clear, please post your
questions here. Note Avisynth has trouble with 20+ files per group (see post #3).

If for some reason you want to encode from the command line, you can do that.
I explain how it's done using VirtualDub here, and using ffmpeg here.

Thats it! Please give it a try and let me know what you think!

From the README:
FrapsJoin: rename Fraps videos grouped by recording
    Fraps (
Fraps is a program that captures Windows gameplay as AVI video files. For reasons
of backward compatibility, the video files are limited to 4 GB in size, so a long
recording will consist of many 4 GB movies that must be joined with a video editor.
This is a source of annoyance for many people and has widely been regarded as a
bad move.
This little script attempts to mitigate the situation by renaming the videos,
grouped by recording. All files which represent a continuous recording are given a
common name, followed by a 3-digit serial number. The files can then be joined
automatically by VirtualDub, and possibly other video editors.
FrapsJoin can also generate *scripts* for three different application: Avidemux,
Avisynth and Virtualdub. In addition, you can write your own postprocessing commands:
* using Avisynth, you can do color correction, resizing etc;
* using Virtualdub, you can do that too, plus you can set compression
  settings and save the final video if you wish. You can run the script
  using VirtualDub's command line interface (vdub.exe).
Review the included INI file and samples for help & more options.
  Copy the FrapsJoin project files to any location, eg,
  "<My Documents>\FrapsJoin". Then choose one or more
  of the following ways to use the script:
  * SEND TO mode installation: right-click the script, "Copy";
    in the Explorer navigation bar, type "shell:sendto", Enter;
    right-click in the Send To folder, "Paste Shortcut"
    To launch, right-click any AVI file in your Fraps folder,
    select "Send To", FrapsJoin
  * DRAG AND DROP MODE installation: right-click the script, "Copy";
    right-click on the Desktop, "Paste Shortcut"
    To launch, drag any AVI file in your Fraps folder to the
    FrapsJoin shortcut
  * To launch in OPEN WITH mode, right click any AVI file,
    "Open With...", browse to FrapsJoin.bat; 'FrapsJoin' should be
    retained in your "Open With" menu for future use.
  * Capture some video with Fraps...
  * Go to the capture folder in Windows Explorer
  * Launch FrapsJoin using one of the three ways described above;
    for each group of videos you will be prompted for a 'group name';
    hit Enter to accept the default (default = first file name)
  * Open the first file (suffix "-00") in VirtualDub; then use File menu,
    "Append Avi Segment...", select the next file in the group (suffix "-01"),
    and check "Autodetect additional segments"; VirtualDub does the rest.
    I am user 'raffriff' on, an unofficial Fraps discussion board
    This is a modest update of a contribution by user koala85 on the above forum.


Staff member
Site Contributor
EDITED Jan 20 - merged 2 scripts into one (the previous script generated an Avisynth script without renaming; the new one only renames by default, but still has the option to make an Avisynth script)

There were some limits to doing it the old way. The maximum number of files that can be joined with Avisynth is about 50 (and the memory usage goes wild), but I joined 96 191 test files with VirtualDub very easily, using a version of koala85's script [link] which works by renaming Fraps files in a way that VirtualDub understands.

I would be interested to hear what people think after working with the script for a while.

I have very little (read: no) experience with VBS scripts, but I would really like to give your script a try! the only problem is, whenever I try to run it via the "Open with..." method (the only one I have tried), I get a permission denied error after confirming the name. I have checked the permissions on all my folders. What else can I do?

Thanks so much!


Staff member
Site Contributor
Thank you for trying it. Sorry about the error...

Is there any other information in the error massage? If so, could you post the exact text, or a screen grab?
(what kind of permission - "file execute", "antivirus warning"?)

BTW I'm looking into making a GUI for this...
thanks so much for the quick response. But I went out to get dinner, came back, and it works... so what a great bit of programming! Works well, and fixes itself!
Hello, i just want to say, amazing looking script, but i do encounter an error when i try and use the Send To method, i get the Error, Windows Script Host Can't Rename Files: Permission Denied.
Any help?



Staff member
Site Contributor
Thank you for your kind words. I'm glad you like it!

For your permission error,

1. Make sure no files are being used by another application (this includes antivirus, media indexers etc)

2. What folder are you using? You may need to set folder permissions.
  • Don't use a folder under Program Files; these folders require special permission.
  • It's best not to record to your C drive at all. If you must, then use C:\Fraps\Movies
  • Right click folder, Security tab.
  • Allow all users Modify (including rename) permission.
  • Hit Apply.
  • If asked, allow new permissions on all files and subfolders.