Simplistic seems to work. I did the same thing that you had done, and it works:
ffmpeg -y -f mjpeg -use_wallclock_as_timestamps 1 -i "http://localhost:5432/screenshot?stream=y" -t 10 FGTest.mpg

... input and a url of http://localhost:5432/screenshot?window=WindowA&stream=y All it seems to capture is a single frame. i don't know where you ... smoothed out but was still flashy... i don't know but i suspect that ffmpeg should still be able to work with it... i think the key is the "type=jpg" ...

Yes, I can just do a screen capture of any screen, FlightGear or other, and that does work.
But, in the past FlightGear was able to output a stream of motion jpegs and ffmpeg could directly capture those. It seems like that feature no longer works.
If I get the chance, I will look through the code.

In the past I've been able to capture a video stream from FlightGear based on this: https://wiki.flightgear.org/Phi#Motion_JPEG So, I've just run fgfs with --httpd=5432 Then, I could run: ffmpeg -i "http://localhost:5432/screenshot?window=WindowA&stream=y" ...

... and is something that OSG supports out of the box - there are number of ffmpeg related osg examples, but it's nothing that is currently integrated ... the frame buffer and pass it onto another handler, to save to disk, or stream the window contents to another process. As a matter of fact, ThomasS ...

... about the opportunities for improving this solution by something like ffmpeg. Even though I totally agree to you, I have to say I won't be the ... http://localhost:8080/screenshot?window=WindowA& stream=y same as before, but not just send a single image but a motion-jpeg ...

... and you also understand how to adapt the built-in httpd server to stream the whole thing. The lowest hanging fruit to make this work much better ... osgmovie.cpp - and some more streaming related resources - for example, ffmpeg/gstreamer examples are often shared by people on the osg-users list. ...

I have had some success with using ffmpeg to capture a portion of my screen (live) and format it as a web based video stream and then receive the video stream with an opencv program framegrabbing and processing. Also, maybe ...

When I have done this I've used something like ffmpeg to capture a portion of my screen, encode, and transmit it as a video stream.

... I changed it. I'm not. I can't reproduce a crashing FG using the mjpeg streamer here. If you have a gdb stacktrace or a coredump, I might have a ... way. Video streams are better implemented using a stream encoder like ffmpeg or alike (not implemented yet). Torsten

Concerning external tools, you could use streamed httpd images and post-process those arbitrarily using a chain of VLC/GIMP ... without requiring any modification/configuration of FG, but can use a pipe to ffmpeg/libav and such you can achieve what you want indirectly, provided this is ...

... libmjpegtools-dev cdda2wav libavcodec-dev libtheora-dev libavutil-dev ffmpeg-dbg libgtk2.0-0 libgtk2.0-0-dbg libgtk2.0-bin libgtk2.0-common libgtk2.0-dev ... press right mouse button on gnome-sound-recorder or Audacious stream, select Move Stream, and move it from Alsa PCM to Monitor Source of ...