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| Athlon CPUs http://forum.linhes.org/viewtopic.php?f=15&t=4970 |
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| Author: | crabby [ Sat Jun 18, 2005 5:04 pm ] |
| Post subject: | Athlon CPUs |
From what I have been reading HD playback requires a 3GHz class CPU. Does this include an Athlon XP 3000+? I know they don't actually run 3GHz but I've only seen refrences to Pentiums. I'm hoping I can get a slot-A cpu so I don't have to get a new motherboard. I'm running R5A16 and will be playing back at 720p most likely. Thanks! |
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| Author: | Liv2Cod [ Sat Jun 18, 2005 6:33 pm ] |
| Post subject: | |
If you really mean a SLOT-A motherboard, you're out of luck. I think the fastest Athlon in the slot-A package is something like 1200 MHz. If you're talking about SOCKET-A, then you can get the AXP-3000. I tried to use an ATX-2500 and -2800 processor without complete success. My HDTV viewing was choppy and not really acceptable at 1080i output. This was using an nvidia 5200 card and XV, not XvMC. I think XvMC would have made the difference, but it was (and is) just too unreliable for a production box. |
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| Author: | ceenvee703 [ Sat Jun 18, 2005 8:47 pm ] |
| Post subject: | |
Just wanted to say that I have had MUCH better luck lately with XvMC. Thanks to XvMC I was able to watch the entire 2 hr Lost finale via my remote frontend (a Shuttle nForce2 motherboard with Athlon 2400+ CPU and FX5200 video card) with no stutters or crashes. I was pleasantly surprised after flaky XvMC freezes and crashes in the past. |
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| Author: | crabby [ Sat Jun 18, 2005 9:32 pm ] |
| Post subject: | |
thanks. yes, i meant socket-A! sorry aboot that! i currently have a 2400+ and fx5200. i'll see how far i can get with it. i'll give xvmc a shot but i wasn't going to count on it since i've heard bad things and i don't like the osd, but it is worth checking out. if it doesn't work out i'll go for the 3000+. thanks! |
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| Author: | Xsecrets [ Sun Jun 19, 2005 7:01 pm ] |
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I don't think any athlon socket A processors are up to the task of 1080i without xvmc, though many of them will pull off 720p, but leave no room to spare for other processes. And despite the previous posts enthusiasm about xvmc he is the only person I have seen thus far having success with it. |
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| Author: | ceenvee703 [ Mon Jun 20, 2005 5:56 am ] |
| Post subject: | |
Back when I got my HD3000 card, I certainly had the kind of problems Xsecrets is referring to: playback froze whenever the on-screen display came up, stuff like that. That was with the original drivers and an early version of R5 alpha. Just to be specific, I'm seeing success with R5A16 (MythTV 0.18.1) on my remote frontend, the DVB drivers on my backend (default card settings, not sure if that's transport stream or program stream), using the Nvidia 7174 drivers, displaying to either a 540p (backend) or 720p (frontend) monitor, and using the directions found in this thread if necessary: http://mysettopbox.tv/phpBB2/viewtopic. ... vmc+nvidia This thread suggests it might be an 0.18.1 improvement: http://gossamer-threads.com/lists/mythtv/users/131782 Also to clarify what works and what doesn't, for me: I never try to watch Live TV via the HD3000 (I've got a set-top box for doing that), the OSD is still gray when XvMC is on, and there is some picture breakup while the OSD is on screen but it clears up after a couple of seconds. It's easy enough to switch XvMC on under Playback preferences and see if it works for you or not. |
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| Author: | Greg Frost [ Mon Jun 20, 2005 6:18 am ] |
| Post subject: | |
ceenvee703, can you check what your CPU usage is when playing back high def? Also, what is the format of the content (720p, 1080i ?), and what de-interlacing do you use (assuming that some of your content is broadcast interlaced). |
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| Author: | benjohnson [ Mon Jun 20, 2005 6:56 am ] |
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I would think that you'd be right on the edge with a 2400+. I have no problems wacthing recording with a 3000+ and every once in a while I have some problems with a 1080i stream with my 2500+ frontend. I used to have a stuttering problem with live tv with the on my 3000+, but I changed my /cache partition to tmpfs and and it works much better. Well aside from taking forever to change channels and audio not always working, but I am using R5A12 and not a more recent build where that is reported to be fixed. I haven't tried live tv with my 2500+ frontend, just haven't had the time. One note is that I turned off deinterlace on the frontend 2500+ I'm viewing it through a 13" tv in my bedroom and I really couldn't tell the difference, and it disabling it made playback smooth. I guess it is also noteworthy that I don't use lirc, I have a IR keyboard that I mimic with a programmable remote. ( I have read several people saying that lircd takes an amazing amount of resources for what it does). I also turned off the ability to process jobs, because when it would start I would get a big jerk in my picture, but If you could live with that it works fine. |
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| Author: | ceenvee703 [ Mon Jun 20, 2005 7:33 am ] |
| Post subject: | |
Greg: I'll try to check CPU usage tonight. I seem to be mainly recording stuff from the 720p broadcasters in my area (Fox and ABC) so maybe not needing to deinterlace is helping quite a bit. I am pretty sure I have tried it with 1080i broadcasts--playback might be a bit rougher if I remember correctly. Tearing appears from time to time. I'll try that tonight as well. I've got Bob 2x set for deinterlacing. Ben: my system absolutely can't play back HD recordings without the XvMC assist. Also, interesting point about LIRC: I'm not running it on my remote frontend either--I'm using the Remote Wonder which doesn't need it. |
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| Author: | ceenvee703 [ Mon Jun 20, 2005 7:28 pm ] |
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OK, here's what I tried and what I got: On my master backend machine (a Chaintech 7NIF2 motherboard, 540p modeline, using onboard nForce2 video, other setup as mentioned above), tried to watch a 720p recording of Men In Black II with XvMC turned off. top reported CPU usage of 97%. I think it would have been higher but one of my PVR cards was recording something at the same time. Turned on XvMC and CPU usage dropped to around 40%... I saw usage as low as 25% and as high as 50%. On my remote frontend (Shuttle SN41G2B, 720p modeline, FX5200 card), playback of the 720p material with XvMC turned off gave 99% CPU usage. I turned on XvMC and CPU usage also dropped to around 40%. I tried a 1080i recording of Las Vegas on my remote frontend. Didn't bother with XvMC off. With XvMC on, CPU usage was around 45%. I will try to let the entire 1080i recording play to see if it crashes my remote frontend. |
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| Author: | benjohnson [ Mon Jun 20, 2005 8:55 pm ] |
| Post subject: | |
ceenvee703: Something funny is going on if you can't watch 720p with at least one of the systems you have. I was able to watch 720p recording with a Athlon 1700+, before I bought my 3000+ and upgraded that machine with thw 2500+ I had been using. I'm not really sure what the hardware differences are. In both cases I'm using an Nforce motherboard (neither are using dual chanel memory), a Nvidia video card 5200 and 440mx at least 256mb of memory How are you actually getting cpu statistics, I never really figured out how people claim they are measuring load. I can't get reliable load numbers, sometimes when I'm watching a HDTV stream ps and/or top tell me mythfrontend is using 10%. I can't beleive that. If you told me how your measuring load, I could tell you what load I'm running doing some set tasks. Oh, yeah what Knoppmyth version are you running. Myabe I won't upgrade if it's the new version. It is funny I've some people's athlon systems work fine and others don't. As far as I've read both here and at the gossamer threads, nobody knows why. That's why I keep encouraging people to try it. who knows maybe it works for them. (on another note it doesn't matter if I use ff whatever its called or libmpeg) As an aside: Maybe somebody can answer this query 1GHz*32bits / (1080*1920*30) = 514 operations to handle each bit displayed. That's worst case. With compression and processor instructions designed to handle multimedia, why????? Is linux that inefficient? |
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| Author: | Greg Frost [ Mon Jun 20, 2005 8:56 pm ] |
| Post subject: | |
Thank you very much for supplying those data points. |
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| Author: | benjohnson [ Mon Jun 20, 2005 9:02 pm ] |
| Post subject: | |
Oops Divide that final number by 24 (forgot color) and youstill have 21 instructions. OK, that's a little worse but I still feel it should be more thatn enought power. |
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| Author: | Xsecrets [ Mon Jun 20, 2005 9:07 pm ] |
| Post subject: | |
well it's not just displaying the information that uses up all the cpu. If you had uncompressed video it could display it no problem, however It already takes about 7G/hr with mpeg2 compression for 1080i if it was uncompressed you'd have to have a terabyte raid just to record a few hours. What's using up all the cpu is trying to decode all the info in real time. |
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| Author: | tjc [ Mon Jun 20, 2005 9:52 pm ] |
| Post subject: | |
Stop and think of the number of steps between recorded data on the disk and bits on the display. 1) Read the data - DMA helps a lot here but there is still the matter of making the request, handling the interupts, ... 2) Decompress and decode the data 3) Send the data to X - this goes via the network stack even if it's "only" the loopback device and memory mapping buffers... 4) Actually feed the bits to the video card via the driver... Not only am I'm leaving steps out, but other stuff is happening at the same time, keeping the system clock uptodate, handling IR events, scheduling processes to run, memory management, running the sound drivers in sync, running any video filters that you've got,, scaling the output to the display size, ... |
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