Windows – How to install libav manually for Video Download Helper on Windows 7

browser-addonsfirefoxfirefox-extensionslibavwindows 7

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.

Best Answer

Solution

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

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\DownloadHelper\ConvertHelper3]
"InstallFolder"="C:\\Program Files\\ConvertHelper3"
"Version"="3.1"
"Is32Bits"="no"
"ReliableVP9"="yes"

Background

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

VDH looks at the registry for this key:

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\DownloadHelper\ConvertHelper3\InstallFolder

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:

https://builds.libav.org/windows/release-gpl/libav-11.3-win64.7z

This is the general download folder for builds:

https://builds.libav.org/windows/
Related Question