> 2. I could make some videos after some trials but the quality is poor.
> I have three significant problems (running FG reduced at 800x600)
> a) FG has very reduced framerates and runs stuttering (40 frames versus 85)
So far I've tested on two machines and for the default 10 fps stream
and format=rgb, I get about 20% decrease of FG fps (say 9xfps -> 7xfps)
The current implementation is unfortunately not the quickest thing.
The bottle neck is reading GL's framebuffer pixels, and hence why a
smaller FG window would help. And there isn't a way to easily grab it in
a smaller scale. I've been suggested I could do something like render to
texture, and I'll have to look into that later.
At the moment, this screen streamer should hopefully serve a more
efficient way to capture FG video, comparing to using an external app
(e.g. xvidcap), or using FG's jpg-httpd.
The simplest benchmark you can test is have FG running, and then
watch FG's fps while running:
wget -O /dev/null http://localhost:20000/?format=rgb
vs
wget -O /dev/null http://localhost:20000/?format=rawrgb
vs
wget -O /dev/null http://localhost:20000/?format=mpjpeg
(if you have jpeg support enabled)
rgb and rawrgb should be very much the same, rawrgb is in theory the
fastest.
Also notice with scale=2 or 4, it actually won't speed up FG itself,
as there's actually a bit more work for it to do. The simple scaling I
did is mainly for bandwidth saving on the network if you happen to
stream things over the network, or if you want to give less work to the
video encoder/player.
(Perhaps I should document all these as well :)
> b) The resulting video is quick-motion (time accelerated)
Sounds like the fps from the streamer doesn't match the
encoding fps. For ffmpeg that would be -r.
> c) ffmpeg stops sometimes recording after a short time (not fixed, I
> noticed from 3 to 13 sec).
Odd, not sure what the cause is. Alternatively, you can always save
the stream into a file first and encode it later. If you have a
reasonably fast disk that can also help the performance during the
streaming.
Thanks for your test and input.
Pigeon.
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