I have an application that generates a series of images (QImage) and writes them to disk as a video. I am encoding the video using an external FFmpeg process, which I start and communicate with via QProcess. I feed this the images via its stdin, using QImage::save to write them to the QProcess in BMP format (FFmpeg options '-f image2pipe -c:v bmp -i -').
This works fine on Linux. On Windows, it is APPALLINGLY slow; on the order of seconds per frame. Also, on Windows, it takes a very long time (minutes) before even the initial output from FFmpeg appears. (I'm using QProcess::ForwardedChannels, although switching to default and just letting the output buffer doesn't seem to make a difference.) The problem *seems* to be with QProcess; running FFmpeg in a shell seems to have reasonable performance. It's almost as if running the process through QProcess is causing it to execute extremely slowly. Has anyone else encountered anything like this, or have any idea what might be going wrong? (Note: This is with Qt 4. Upgrading to Qt 5 is not an option at this time.) -- Matthew _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
