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I guess the question is do we drop more frames on same content on 8.1 Intrepid vs earlier 8.04 Hardy?
I have just pulled trigger on the new ASUS board for HDMI output so I'll have something here to test soon enough. I am also taking some BD rips over to the other machine so I can test on it too. If there's anything I can do to help I will be happy to try - not sure I am quite up for kernel recompile though without the EZ-bake version of the directions <sigh>
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So it's not the lack of real multithreading the problem, but the worse resource utilization on Intrepid vs. Hardy kernel ?
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I tried the latest Jaunty alpha Kernel, with the latest XBMC SVN and...
well not so obviously like with Intrepid but still the performance is a lot worse. A lot of dropped frames with the 1080p content played without a dropped frame on Hardy.
I really can't belive that even with a 3Ghz Core 2 Duo CPU one can not play a 1080p movie without droppped frames, whilest the same movie is perfectly playable on the windows version of XBMC on a 2Ghz CPU with 70% utilization.
If i do the math, i can not come down to any other problem that (whatever the core utilizations show in XBMC) the video decoding is working single threaded on kernels newer than 2.6.24. I still think it is some compile option we need to change for ffmpeg to cope with the new kernels.
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Have any of you tried it with the CPU set at full, i.e. Performance mode, or disable Cool N Quiet?
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WRONG, as I said before the decoding _IS_ still threaded. Halt execution with a debugger and have a look at the threads, there are three from libavcodec. The problem is that they are apparently being scheduled to the same core for some reason, which ruins the whole parallel thing. Have a dig through LKML and look for changes involved in the process schedulers. Also find out _which_ scheduler Ubuntu is using and what applicable patches if any they are making to the kernel. It would also be interesting to see results from similar kernel versions on other distros.
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I don't have an Ubuntu box handy here, but can anyone check in system monitor what the "nice" value of the decoding process is?