Qt + Phonon: doesn't play on some computers

4
votes

I have a problem with my application after deploying to a clean machine. These are the results of running the application:

  1. Win7 Home: After installing ffdshow the program plays wmv, mp3.
  2. Vista Home: With ffdshow installed, it plays mp3, but not wmv
  3. WinXP (without service packs): Doesn't play wmv, mp3, even with ffdshow installed. The program can find 38 backends, mp3 and wmv are among them. It does play wav files.
  4. Everything plays just fine on the computer where the project is built, even if many formats are disabled in ffdshow.

The plugins folder is put besides the exe file and contains a phonon_backends folder with phonon_ds94.dll.

Can someone explain me how to make the program play files on computers where Qt is not installed?

3
windowsqtmedia-playerphonon

3 Answers

2
votes

I am not sure about the mp3 files not playing, but did you remember to deploy QtOpenGL4.dll as well on the machines that won't play video? On Windows, the Phonon backend relies on this DLL and will just silently sit there and do nothing when it's not present.

Sjwarner's suggestion to try Dependency Walker is a good one, especially in cases like this where plugin DLLs are dynamically loaded.

1
votes

This first thing I'd do is to give Dependency Walker a go. I'd run it with all of the deployed states you've detailed above and see if there are any differences between the dlls used by the app in each case.

0
votes

I was having this exact issue, and I fixed it by installing a codec pack. This is the one I used: K-Lite Mega Codec pack (be sure NOT to install the two browser add-ons at the end)