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CPU too slow or only wrong settings playing x264?

Posted: 07 Oct 2006 15:13
by JMS
I tried the sample track from this thread on my Pentium D830 machine - Dual Core with 3GHz each. It played fine until the first matrix scene. Then the picture freezes and at the end of this animation scene after some jerky frames it continues - until the next animation.

I tried 0.9.0 nightly build and the 0.8.5. For the later one the debug log reports a couple of late pictures but without a time stamp - although I guess that's exactly the problem.

Is there any chance to get this running by changing the display settings? I should add that MPC (Media Player Classic) with the PowerDVD7 (CyberLink) Decoders plays all of the track with no problems even with a bit less of CPU usage. Although in the animated scene the second core is heavily activate (40% overall to above 80%) but the video is displayed without interruption.

Can VLC use the second core to get the same result?

Thanks

Jochen

Posted: 07 Oct 2006 18:41
by Trax
H.264 decoding takes a LOT of CPU and in most cases the system is just too slow.. VLC uses FFmpeg's H.264 decoder and that doesn't do multithreaded decoding for H.264 so having dual CPU (or Hyperthreading) won't help you.

You can get a performance boost by turning off the deblocking loop filter: Settings, Preferences, Input / Codecs, Demuxers, Other codecs, FFmpeg, Skip the loop filter for H.264 decoding, change to All.

Save the preferences, restart VLC and try again.

P.S. x264 is actually an encoder library, the video codec is called H.264 (also known as AVC or MPEG4 part 10).

Posted: 07 Oct 2006 19:41
by JMS
Thanks for the information. The setting improved the display (esp. CPU reduces to around 28%) but didn't fully make it during the animation scenes (although most of it is now shown).

Bye

Jochen