**@matteo:**

**Every build** of FFmpeg has its quirks, but I'm surprised such a simple command string doesn't deliver the expected results for you. Even if you have a strong reason to hold on to your current version, you can keep any number of builds at hand. I currently have two in my `%PATH%` directory, named `ffmpeg` and `ffmpeg2`. (Possibly useless if not using a static build.)

**If you would like** to test your build against my input files and batch commands, I have [uploaded everything to a GoogleDrive][1] where they are freely available.

**I have also** uploaded my [FFmpeg console output][2] and some file size/media length information to Pastebin in case it might help with debugging.

**Pastebin links** to:

 - [FFmpeg console output][3]
 - [MediaInfo for final Flash video file][4]
 - [MediaInfo for audio input file][5]
 - [MediaInfo for still image input file][6]

**GoogleDrive links** to:

 - Input audio file [narrate.wav][7]
 - Input image file [still.png][8]
 - Batch file [batch.bat][9]
 - Final output video file [final.flv][10]

You are also welcome to upload anything to the [folder named Stack Exchange][11], I'll be happy to test your input files against my build. Obviously I've got very little to do over the weekend.


  [1]: https://docs.google.com/folder/d/0BxafXIRt8NlPRk94QWd5aDBQdm8/edit "link to complete folder"
  [2]: http://pastebin.com/c5uu0upQ "FFmpeg console output"
  [3]: http://pastebin.com/c5uu0upQ "FFmpeg console output"
  [4]: http://pastebin.com/CxW9s1sz "Flash output MediaInfo"
  [5]: http://pastebin.com/Z01yEphW "Audio input MediaInfo"
  [6]: http://pastebin.com/UPYnZLi8 "Still image input MediaInfo"
  [7]: https://docs.google.com/open?id=0BxafXIRt8NlPSzEwWGxMRmY3RGs "Input audio file"
  [8]: https://docs.google.com/open?id=0BxafXIRt8NlPbHZYM0tLWWtzeWc "Input image file"
  [9]: https://docs.google.com/open?id=0BxafXIRt8NlPUmxvUmtjYW90LWM "Batch file"
  [10]: https://docs.google.com/open?id=0BxafXIRt8NlPREZaZ0dkR3VGVFk "Final Flash video file"
  [11]: https://docs.google.com/folder/d/0BxafXIRt8NlPRk94QWd5aDBQdm8/edit "Open folder"