I solved by myself, maybe. In the constructor of TextEdit, after textEdit = new QTextEdit(this); add QTextCodec::setCodecForLocale(QTextCodec::codecForName("UTF-8")); then I could save .md file as encoded by UTF-8. Without this, .md file will be saves as shift-jis (system's default). .txt files are always saved using UTF-8 encoding without the added line.

I'm as surprised as you that I don't have at least one codec... I'll try installing other codecs packages and have a look at VLC's Qt Wrapper but I mainly choose to use QMediaRecorder to reduce any other inclusion of librairies. Thanks for the info, I'll keep you up-to-date.

Sorry, I misunderstood your post but currently, except for QMediaRecorder, I don't know if there's a way to have the list of decoders.

Hi, 32bit Windows 7 Home Edition. Anyway maybe I found a workaround. In case an error occurs when trying to play the movie, there is a maximum number of retries... I have done this because my suspect is that, due to the CF-19 "poor" performances, the libraries aren't (fully) loaded when the movie is played. I will keep you up to date whether this is or this is not THE solution, for anyone else's benefit. Thanks to everybody!