Jens Baumeister <[EMAIL PROTECTED]> writes: > On 1/9/06, David Abrahams <[EMAIL PROTECTED]> wrote: >> >> I notice that the performance of playback seems to be suboptimal. For >> example, I captured some HDTV video over firewire using MythTV. When >> I try to play it back using the frontend, it is totally unwatchable. >> > [...] >> However, when I use VLC to play the same file, it looks almost >> perfect > [...] >> And if Darwin-specific playback >> code turns out to help, doesn't it indicate that the playback code >> MythTV is using for all other platforms today could be a whole lot >> more efficient? > >>From what I've read, there isn't much PPC or Darwin optimization in > MythTV - at least not in the releases. I don't know about SVN.
AFAICT, there's no processor-specific optimization in playback at all. So if performance is bad on PPC/Darwin, it's probably bad (compared to what's possible) on x86/Linux as well. > I use 0.18.1 on an old 550 MHz G4 PowerBook with 768 MB RAM as my > kitchen frontend with nothing else running on it, and it just barely > handles the task. (E.g. it starts to stutter when mythtvosd scrolls > something through the frame.) OTOH my master backend ist a Gentoo > PIII 600 MHz with only 256 MB RAM (I know, I should buy some more...) > which also doubles as my living room frontend and usually has other > stuff (server apps, iPod transcoding, commercial flagging, etc.) > running in the background - yet it feels a lot more responsive than > the OS X frontend and hardly ever stutters. Ouch, really? Not good news for the MacOS folks. I wonder what about the MacOS frontend is sucking so badly? I am running a frontend/backend combo on a 1.42 GHz Mac Mini (admittedly it could stand a RAM upgrade from 512M to 1G, but I don't think that's the issue) and I see a *lot* of beachballs. Maybe I'd be better off buying a cheap linux box, but I really like the "just-works appliance" nature of the Mac for this purpose. Any idea how I can find out what the problem is? I don't imagine profiling will make a huge difference in such a highly threaded application. > I've spent some time setting up setuid permissions and process > priorities on the Linux box, but I don't think I'll manage to squeeze > much more performance out of the OS X frontend doing that. Why not? > So I' can't vouch for possible x86 optimization, but I'm pretty sure > the code could be tweaked to run faster on Darwin/PPC. Can you explain why you are pretty sure of that? Thanks, -- Dave Abrahams Boost Consulting www.boost-consulting.com
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