Can't find avformat.dll - Windows 10 - Audacity 3.1.3

Despite following the instructions and multiple tries, I cannot get Audacity to recognise the avformat.dll file under Edit>Preferences>Libraries or in the Export Audio dialog. See the attached report of a session where I tried to load the dll under Edit>Preferences>Library.

Any and all help appreciated.

Kind regards,
Ken (10.1 KB)

Assuming that you are using the 64-bit version of Audacity 3.1.3:

  1. Go to
  2. Download “FFmpeg v2.2.2 INSTALLER (.EXE)”
  3. Run the FFmpeg installer (all default settings)
  4. Launch Audacity

Audacity should find FFmpeg automatically.

  1. Test: Try importing this file:

I am having the same problem and am using the 64 bit version of avformat.dll. Didn’t have the issue Audacity 3.1.2. I was able to get one MP4 converted to audio. Now Audacity is saying it cannot find the file. Have reinstalled everything and still cannot find the DLL. I have manually pointed Audacity to the DLL in my case C:\Program Files\FFmpeg For Audacityavformat.dll When I restart 3.1.3, it still says cannot find avformat.dll. I even copied the avformat.dll along with the outer DLL files into Audacity’s directory and still could not find it.

I reinstalled 3.1.2 and discovered this:

  1. Launched Audacity 3.1.2
  2. Looked at the preferences and Audacity had found avformat.dll in C:\Program Files\FFmpeg For Audacity
  3. Closed Audacity
  4. Launched Audacity
  5. Right Click on an MP4 file
  6. Left Click on Open With
  7. Audacity launches
  8. Audacity gives error that it cannot find the avformat.dll
  9. After a manual search for it. Audacity still cannot find it.
  10. Close Audacity
  11. Open Audacity
  12. Click on File
  13. Click on Open
  14. Find an MP4
  15. The MP4 Opens
  16. If Audacity is already Open, I can right click on a MP4 file chose Open With → Audacity, and it will open properly.

Conclusion with 3.1.2, Audacity is trying the read the MP4 before it loads the avformat.dll.

I decided to reinstall 3.1.3. My conclusion remains the same as for 3.1.3. When one does the above Audacity operates the same way when I follow the above steps.

I believe that Audacity needs to wait for everything to load before it tries to load a file.

Thank you,


The log file contains (among other things) the following entry:

Error: Failed to load avformat-55.dll (error 193: %1 is not a valid Win32 application.)

After trying various things without success, I downloaded the FFmpeg zip file from the LAME website ( > FFmpeg for Windows and latest Audacity versions > FFmpeg RECOMMENDED ZIP OPTION:, which contains the 32-bit version of avformat-55.dll. After selecting this dll version in Preferences > Libraries, Audacity works as it should.

‘W32’ in the error message refers to Windows 32-bit. Audacity 3.1.3 is 64-bit (at least that what is claimed) and the recommended avformat.dll is 64-bit, but apparently the code actually expects a 32-bit version.