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View Full Version : MBA Rev B Video and EyeTV stutters




bubbleboy76
Dec 1, 2008, 04:07 AM
I have had my MBA 1,86GHz rev. B SSD for a week now, and I will send it back to Apple Store, and go for a MB instead.
I am using Plex as mediaplayer, and with my old white MacBook C2D 2.0GHz from 2006 I could play 1080p videos with no problem. The same movies stutters on the MBA, and the fan is loud.
Now I have to sell the external soundcard I bought just to be able to get 5.1 digital sound out from the MBA.
My test movies are 1080p encoded in h.264: Planet Earth in ts container, and Letters from Iwo Jima in mkv container.
I really thought that the faster bus, memory and disk would compensate for the lower clock-speed comapring to my old white MB, but it did not.
Probably in the future some mediaplayer will use hardware-decoding in the GPU, and then the MBA can be used as HTPC. But I can not wait for that, I want to watch movies now!
There are also a small problem with EyeTV. When choosing the highest level of deinterlacing (progressive scan), there are also stutters. This also worked fine on my old MB.



bubbleboy76
Dec 1, 2008, 04:24 AM
One clarification. I have tried all levels of h.264 video-quality (the new setting that came with Plex 5.22). But it still stutters.
I have also tried playing the movie from the internal drive, from a external usb-drive, and from the network. It does not make any difference either. So to me it is clearly a lack of CPU-speed that is the problem.

Out of curiosity I have also tried the 'killer_sample.mkv' on different late 2008Macs. It does not stutter on an iMac 24" 2.8GHz, but it stutters on the MBA, MB 2.0 and MB 2.4 (Using Plex 5.22).

I display the video on an 720p projector, connecting with the displayport-dvi adapter.

jharju
Dec 1, 2008, 05:11 AM
I would blame Plex. It has huge issues with cpu usage. I have my mate's rev B MBA here and plex takes all available cpu even when just idling. This happens also with my 24" iMac. Only mac that works with plex is my Mini.

Try to play those mkv files with VCL, QT (with perian) or with Mplayer extended. Should play fine.

bubbleboy76
Dec 1, 2008, 07:13 AM
Now I have tried the latest versions of:

Quicktime with Perian
MPlayer Extended (tried all video settings for frame drops etc)
VLC
XMBC For Mac

As I expected, they all play these videos far worse than Plex does (except XBMC for Mac, which is more or less the same video-code as Plex). Some of them even stutter on the audio.
Plex is much more effective than the competition, but it still can not play these videos without some stutters on the new MBA.

I will go for the MB 2.4GHz.

jharju
Dec 1, 2008, 07:47 AM
Plex is much more effective than the competition, but it still can not play these videos without some stutters on the new MBA.
Yes, that's correct if Plex is working like it should. Have you tried to just start Plex (without any video) and after that open activity monitor and take a look how much cpu plex uses when just idling?
For me Plex is not working at all. CPU usage is 170% when just idling. Whole computers stutters and I have to force quit Plex everytime. And this with exactly same computer that you are using (and also with iMac)

But I found MBA rev B to be almost identical to rev a model. My friend had issues with a rev computer (core shutdown, performance locked to .800GHz etc) and after three unsuccessful repair Apple swapped whole computer to new rev b 1.86GHz/128SSD model.

Biggest advantage is the new nVidia graphics. After that there seems to be really minor advantages. I think rev a was a bit warmer under load and fan seems to be more quiet in this model. But when it comes to pure cpu performance I can't see any differences (if we forget HD video). I have used msr tools program to specify cpu speed under load and yet again it seems to be capped to 0.8GHz. Sometimes it jumps to 1.59GHz but goes straight away to 0.8GHz.

bubbleboy76
Dec 1, 2008, 09:14 AM
Strange. My Plex uses no cpu at all after just starting it.
Which version of Plex do you use?
I always turn of all unnecesary features of Plex in the system settings when I install a new version, like web server for example. Maybe that will solve your problem.

justit
Dec 1, 2008, 01:01 PM
Using Plex, I'm getting 41% processor on my Macbook 2.2ghz with 4gigs ram and some fans during idle usage. The code seems to not be optimized (for laptops?).

jharju
Dec 1, 2008, 01:42 PM
Strange. My Plex uses no cpu at all after just starting it.
Which version of Plex do you use?
I always turn of all unnecesary features of Plex in the system settings when I install a new version, like web server for example. Maybe that will solve your problem.
Im using Plex version 0.5.22 but I have also tested 0.7.X beta without any improvements. Im currently using my ht mac mini and Plex is working just fine. It takes about 15-17% cpu when just idling. I have also turned off all the unnecessary features.

But there are still big problems with plex. My desktop is 2.4GHz iMac and plex is not working at all. It takes immediately all the cpu (150-170) and whole system freezes up. Every single time I have to force quit the program. And like I previously said this also happens with my friend new revision B MBA. All the mac's are running 10.5.5 with latest updates.

So with my experience's using Plex I wouldn't be first to blame hardware for stuttering/choppy video.