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Discussion Starter · #1 ·
Hi All,


I need some advice on playback of some files on my htpc. I was watching a 720p version of Mission Impossible 3 last night and it played back perfectly on my 939 socket 3200+ single core AMD computer (Nvidia 7600GT), no dropped frames, great resolution, very happy



This morning I was watching Band of Brothers also in 720p, and every 5 seconds the picture "sped up", I am presuming this means I was dropping frames?


Both files are packaged in an .mkv container, and when i hover over the files, they both say avc1 (the codec used?), Band of Brothers is DTS, and MI3 is Ac3, would that have any effect? Or do I just need a more powerful processor? Is there any way I can get the GPU to do more of the work?


Thanks so much for the help, this forum has been invaluable for gaining more knowledge in these tricky HD times



Sean
 

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Test how much CPU is being used through taskmanager, if it is showing 100% you are maxed on CPU.


This doesn't necessarily mean that the CPU is at fault though. Sounds like these files came off the internet from someplace, it could be whomever encoded them did a bad job, or you have a decoder issue, or could be hardware.


I have the exact same CPU, and although it may be time to start looking for a faster one, I have been playing 720p H264 files (haven't tried AVC1, is this the same as VC-1 that XBox uses?), but I can play them fine. 1080p H264 is nearly maxing this CPU, as I don't have any video card hardware acceleration for this type of file.


It depends on the video card to help with the playback. ATI cards require the X1000 series for hardware help on H264, VC-1 may be the same? X1800 or better is recommended for 1080p H264. Same with Nvidia (certain cards can do hardware accel.). This then requires proper drivers and decoder. I think the 7600 series has the Purevideo hardware acceleration built in for H264 (AVC), like I said I'm not sure where AVC1 fits in, check Nvidia site and your video card documentation.
 

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I checked and it appears AVC1 and h264 is the same. I knew AVC was the same as h264. The confusion is that Microsoft is using VC-1 (awfully similar name), for XBox extender preferred format.


Anyway the statements above for h264 should also apply to you. You may want to try CoreAVC decoder, it may do better, if you can't get a hardware enabling decoder.
 

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I just checked again and in Media Center I get less CPU load than in Media Player 10. Media Player 10 spiked once with Spiderman 3 and froze for a brief frame or two. In Media Center smooth playback. CPU uses ranges from 50% to around 96% (hit 100 in Media Player for one scene of high motion).


This is with same CPU as you, 1080p clips, CoreAVC decoding video and it appears audio (AAC?), ATI x700 card, with no hardware acceleration capabilities (that I am aware of).


720p should be even easier, so all things considered yours should work fine (and probably better than mine if you can get the hardware accel. working on your video card).


I am happy as well, as I didn't want to do any upgrades right now. I plan on using 720p mostly.


Now HD-DVD playback through PC (using Xbox drive) is even more CPU intensive from what I have heard. But I'll cross that bridge when/if I decide to get a drive and go through those headaches with HDCP, or just use analog VGA. I think this will require a dual-core for sure and hardware capable video card. I think they are using same codecs, MPEG-2, H264, VC-1 but higher bitrates?


Does anybody know the bitrates used in the Apple Movie trailers?
 

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Discussion Starter · #5 ·
Hi,


Thanks for the reply, cpu usage is 30% so definitely not the issue, but still definitely dropping frames on Band of Brothers. I have tried WMP and MPC, using coreavc codec, what other reasons can you think of that I would drop frames on this file (apparently it is a good encode)?
 

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There was another post similar to yours, and it was suggested using the Cyberlink package since it supported the hardware acceleration, I think for your card.


Other than trying CoreAVC, that is all I can suggest.


I tend to believe that maybe the file has some problems, as I played several 1080p trailers, and although near the limit they would play in Media Center without skipping, 720p played fine.


Same with the h264 videos that I have encoded myself, but if the bitrate was extremely high, anything is possible.
 
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