On 2015-05-12 14:21, Matthew Woehlke wrote: > 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.)
After further testing, it seems that the problem is caused by writing to the process's stdin? Is there some issue with writing to a QProcess's input pipe on Windows? (We are writing quite a lot - many MiB's - of data...) (BTW, this is with Qt 4.8.6.) -- Matthew _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
