What about the "audio", "mediaservice", and "playlistformats" folders? The "Initial Deployment" told you to copy the contents of the "plugins" folder too.
I did copy everything that's mentioned in the "Initial Deployment" (see below). In my above post I only mentioned what I thought was directly related to QtMultimedia, sorry for the misunderstanding.
Copy the following into C:\Deployment\
The release version of MyApp.exe
All the .dll files from C:\Qt\5.2.1\mingw48_32\bin\
All the folders from C:\Qt\5.2.1\mingw48_32\plugins\
(If you used QML) All the folders from C:\Qt\5.2.1\mingw48_32\qml\
What video format is it? Did you install any codecs on your development PC?
It is MP4 (codecs reported by VLC: Video: H264 - MPEG-4 AVC (part 10) (avc1), and Audio: MPEG AAC Audio (mp4a)). I also tried a MOV and a 3GP video, but none of these can be read by my software on my test PC. But all of those videos can be read by Windows Media Player on my test PC, and also by my software on my development PC with the Qt directory renamed.
AFAIK I didn't explicitly install any codec on my development PC. The codecs set on both PCs match exactly (as reported by Windows Media Player), except for a CyberLink audio codec.
use Sysinternals ListDLLs to show you the DLLs that it uses
Using ListDLLs, I see on my development PC that 10 DLLs get loaded as I open the video. On my test PC, the DLLs that get loaded as I open the video are the 10 same ones, except for the version build number (e.g. 12.0.9600.16477 instead of 12.0.9600.17415). Could the problem be these versions differences? In this case how can I fix this, because even if I distribute the newest versions with my software, the old ones still get loaded.
Thanks a lot