I'm trying to get the Firefox Extension "Video Download Helper" (VDH) to convert and record videos. The suggested way of doing this is to install a precompiled version of libav called "Convert Helper" from the VDH Homepage.

I'm not willing to do that for various reasons.¹

So I want to install libav on my Windows 7 (x64) system and point the addon to the right .exe/.dll/whatever it needs. There is an option to enter a "converter path" manually in the settings, although it does not work for me - probably because I'm not entering the correct path. The entered path just disappears after I click on the "Recheck converter" button. (I'm not really sure if the corresponding field is even made for input. You can see a picture of the settings page here in the "Using conversion rules" section.)

The question is: How do I install libav correctly?
libav provides Windows builds in the download section, but I don't know where to put the extracted files or how to make the Firefox addon recognize the installation. Do I just throw the .dlls and .exes in the System32 folder or probably somewhere in the system's $PATH variable? Is there any other way?

Any ideas are much appreciated.

¹One of them is that they want me to pay for a completely free codec to avoid watermarks which is (a part of) why they appear on libav's Hall of Shame (remark (3/29/2016): the Hall of Shame is removed until further notice). On Linux there's no problem whatsoever (see installation instructions for Linux). Another reason is the fact that I want to have some level of control about what's installed on my system and that "ConverterHelper.exe" obviously is not just a compiled version of the libav codec.

  • I would bet most any reputable codec package for windows would get it installed properly – Moab May 31 '15 at 17:40
  • I've been warned about codec packages and have had nothing but bad experiences with them. I don't like the fact that this does so much more than I want it to. Do you know if there's a way to do a clean uninstall just in case? I would only want to use a codec package as a last resort... But thanks for the suggestion! (And thanks for the edit!) – Piwi May 31 '15 at 17:52
  • I have used klite and shark007 without issue, biggest mistake people make is to install more than one codec package, you should always uninstall your codec package before installing a different brand. Never had issues uninstalling either. – Moab Jun 1 '15 at 12:48
  • I tried that too but failed. Then I checked for alternatives and I found a very good one - deturl.com - it provides a Bookmarklet, you drag it in your bookmarks toolbar - after that, downloading videos works like a charm. I hope this helps. I found deturl in this page: hongkiat.com/blog/download-youtube-videos – BearCode Jul 4 '15 at 22:34


Use a build from libav.org and extract it to some folder.

Create a .reg file with this content and adjust InstallFolder accordingly, e.g., C:\bin\libav-11.3-win64\win64\usr\bin

Windows Registry Editor Version 5.00

"InstallFolder"="C:\\Program Files\\ConvertHelper3"


I powered up a VM and did some analysis of the ConvertHelper3Setup.exe and found:

VDH looks at the registry for this key:


Then it looks at this folder (the default would be C:\Program Files\ConvertHelper3) and checks if there is an executable avconv.exe. If it is, the converter works.

The latest ConvertHelper3Setup.exe (as of 29. March 2016) installs avconv 11.2

I downloaded the newest release (11.3) from libav.org, and everything still works. Can be found here:


This is the general download folder for builds:

|improve this answer|||||
  • Awesome! I can confirm this works and avoids the fishy software. This answers the question. Sadly, there are still restrictions (the watermark already mentioned in another answer remains and the instant audio-only conversion fails - doing it locally works, though). To get around all of these, one would have to simulate the so-called "registration of the converter", which robs VDH of their source of income and might be illegal/against EULA. – Piwi Mar 29 '16 at 15:08
  • It works!!. The watermark is still there. – sandyiit Sep 27 '16 at 18:26

I tried the same and discovered two problems with that: First, at least my version (5.3.1) of VDH seems only to look into \Program Files\ConvertHelper3 for the avconv.exe file, no matter what I enter for the path.

Second, the watermarking is not in the downloaded codec, but a native feature of libav used by VDH to mark the result. So even if one exchanges the libav library, VDH still uses it to place the watermark.

To solve this issue you would need to recompile avconv with leaving out the watermark feature (best ignore it at command line) or put a filter program named avconv.exe which calls the real avconv.exe, but with arguments cleaned of the watermark command. Unfortunately, both solutions are quite a bit of work.

|improve this answer|||||
  • Are you sure about the "Second, [...]" part? How do you know? But thank you for the overview, the latter of your ideas for a solution seems to be a viable path to look into. (In the meantime, I uninstalled VDH completely as I absolutely do not want to support someone violating very user-friendly licenses in such a parasitic, proft-reaping and alternative-free way. As a temporary solution I use Offliberty which is basically the same as deturl.com provided in the comments above, but has a slightly trustworthier look & feel to me.) – Piwi Sep 7 '15 at 22:07

This reply might be a little "tongue in cheek" but I just kicked myself a little for searching this topic in the first place.... Because... (this should be relevant on a superuser forum) every time I upgrade the hardware Windows is running on, the old PC gets re purposed as my Linux box and I run a KVM switch for them. I've tried VMs and used both OS as hosts, dual boot etc... simply recycling hardware seems to work the best - simplest - least complicated etc. Some stuff has to run on Windows and Linux has better tools. Sooo the video that didn't want to convert on Windows... Hit the scroll lock and load the same url on Linux, problem solved :)

|improve this answer|||||
  • 1
    Welcome to SU! :) The downvote isn't mine, but 1) this doesn't really answer the question "How to [...] on Windows 7?" (except you are saying that it's not possible at all), does it? And 2) setting up completely different hard- and software seems like a huge overkill. While I do have a notebook running Linux, it's quite tedious to fire it up every time I want to use the feature, somehow get the link to the notebook, convert it over there and move the file back to the Windows machine. But I see how outsourcing the problem could help (something like a NAS might come in handy)... – Piwi Dec 15 '15 at 1:11

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.