[MPlayer-users] How to pause mencoder
Adam Nielsen
a.nielsen at optushome.com.au
Thu Dec 25 03:43:06 CET 2003
> Sometime nice -19 is not sufficent.
> On my 1GHz athlon, I'm not able to grab from analog tv at 25fps while
> mencoding other video, even at nice -19.
Yes, I can agree with you there. I capture from a digital TV source, so I can
grab 50fps data if I want on a PII/400 running mencoder, but the problem for
me is with mplayer. If I'm running mencoder (on a 750MHz Athlon) and I try
to use mplayer at the same time, it is very difficult to get a full
framerate. I have to use -framedrop to avoid A/V desync, and then every
minute or so the video freezes completely for a second or so. Even -cache
8192 doesn't help (I'm playing the file over a network, and it works fine
when mencoder isn't running.)
I think the problem is that Linux doesn't seem to have a true idle priority
scheduler (although I've seen interesting conversations about the possibility
of this in newer kernel versions.) The problem is that even when running
mencoder at nice -19, it still steals enough CPU power to cause problems
elsewhere. For example, running mencoder at nice -19, and then running
another CPU intensive program (like a second copy of mencoder) at normal
priority, the normal priority program only gets something like 80% of the
CPU. Ideally the nice -19 process should be as good as suspended if
something else is using the CPU (and this is the 'batch' priority they were
discussing.)
> So, sometime, mencoder take longer then I expected and if it's time for
> tv recording I suspend it and resume it later.
So yes, I have to suspend mencoder too if I want to watch something in mplayer
without it being annoyingly jerky.
> Finally, there is at least two good reasons to suspend mencoder :)
But of course, since pressing Ctrl+Z and later typing "fg" seems to work
perfectly, there's not really any reason to add this feature to mencoder.
Cheers,
Adam.
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