Snow Leopard and Stuttering

[a_lo]

I have a white MacBook from 2006, Core Duo 1.83 Ghz and 2 GB RAM.

When trying to play standard XviD files on my external display at 1920x1080 they are unwatchable due to skipping frames. This happens to a much lesser extent with x264 encoded mkvs. This problem has been ongoing for many months and I have tried the various suggestions on topics on this forum but to no avail. In the end I had to downgrade back to Leopard as I need this functionality from VLC. I recently tried again with a freshly formatted/installed hard drive and 10.6 but the same problem still occurs many months later.

It is getting to the point where some applications require me to upgrade to 10.6 and it is frustrating that VLC continues not to work in the same great way it does in 10.5 as it prevents me from making this upgrade permanently.

[Jean-Baptiste Kempf]

So, this means the issue is in the video drivers. try another video output module in preferences.

[a_lo]

Thanks for the reply. So you know, I've got 2 hard drives, one running 10.5 (normal usage) and the original hard disk running 10.6 so I can easily swap in and out to test.

I tried all the different video output modules and none of them improved the situation any more so than the default. Checking the media information showed I was losing either 4 or 5 frames per second. Quicktime also plays the same videos without any issue.

[ajmas]

What is the CPU usage when this happens?

[fkuehne]

Seems like the GMA 950 is unable to provide OpenGL drawing in time for 1080p displays in addition to the internal display. 64 MB shared memory in addition to this control isn't exactly great (regrettably, I'm still having to use it daily as well).

The only "solution" would be using a smaller resolution on the external screen.

[a_lo]

ajmas : I'll update this post tomorrow with that info - I don't have time to swap my hard drives tonight.

Fkuehne : This to me seems like the issue - if I close the laptop lid and simply use the main screen it works fine but this isn't great as I don't want to have to use an external keyboard.

Edit : It's using roughly 19% of the CPU.

[regorg]

I have stuttering problems too with Snow Leopard, and problems seem to have appeared with latest security update or 10.6.4 update i don't know. Since then, whenever i open a xvid file, playback i stuttering from time to time and these messages are written to the system log :
Oct 28 19:49:46 Roger_s_macpro [0x0-0x15015].org.videolan.vlc[179]: [0x10323af38] main input error: ES_OUT_SET_(GROUP_)PCR is called too late (pts_delay increased to 300 ms)
Oct 28 19:49:46 Roger_s_macpro [0x0-0x15015].org.videolan.vlc[179]: header damaged
Oct 28 19:49:46 Roger_s_macpro [0x0-0x15015].org.videolan.vlc[179]: warning: first frame is no keyframe

it happens with all xvid files.
I have an early 2009 quad core Mac pro with 3GB of RAM, with a 24" display (resolution is 1080p). Vlc is 1.1.3 64 bits and i am booting the kernel in 64bits mode.
Any ideas ?
Thanks.

[fkuehne]

@regorg: sorry, no idea. According to VLC's debug messages, your files are broken, but...

@a_lo: the CPU load isn't related to your problem, but your GPU's load. Like you tested for yourself, the only way to support such a large external screen is disabling the internal one.

[tc_2010MacPro]

Hey Guys,

I was having this problem when I was trying to playback blu-ray saved on my 2010 Mac Pro. I thought it was the file, HD, and/or video card. If you go to VLC Preferences -> Click "ALL" (towards the bottom left) -> Input/Codecs -> Access Modules -> MMap: UNSELECT/UNCHECK use file memory mapping. After I did this all my blu-ray playbacks did not stutter anymore.

Hope this helps

[feka]

Thanks tc_2010MacPro. This solution worked for me. It saved me from using iTunes (and give up listening to lots of my songs which happen to be badly organized in terms of id3 tags).

[tc_2010MacPro]

feka - You are welcome. I am glad it helped you.

[a_lo]

@regorg: sorry, no idea. According to VLC's debug messages, your files are broken, but...

@a_lo: the CPU load isn't related to your problem, but your GPU's load. Like you tested for yourself, the only way to support such a large external screen is disabling the internal one.

Sorry for the delayed reply, I had some issues logging in.

With due respect, the problem as you know doesn't occur in 10.5 - has the graphics system changed significantly since 10.6 such that it no longer works? I also did check what the results were if I changed the resolution on the secondary screen lower. It wasn't until I got to 1440x900 and below that it became watchable, but even then there were skipping frames.

To clarify further, on 10.5 I can watch XviD files and up to 720p x264 encoded .mkvs without any issue.