QT Playback issues

I've had the same problem on my iBook G4. It's got a gig of RAM but when I play larger video files they are increasingly choppier. They seem to get gibber every year! I can't upgrade the card in that machine (wouldn't if I could, would be a waste of money).

What card do you have in yours? You may be able to get a better one cheap 2nd hand.

 

IMHO, the bottleneck comes from ... first the CPU, next the hdd.
It depends very much on the codec used too. h264 can be pretty harsh on the cpu depending on the resolutions and etc. on the other hand, the more common divx doesn't require as much cpu power.

GPU (aka video card) shouldn't make such an impact on your system as drivers are generally not so well optimized on the macs, esp. the older macs. in fact, it appears that only the latest portables with the newer GPUs from NVIDIA are able to help out. There's also a recent article (can't recall where, probably from Annatech) that a low end CPU coupled with an efficient GPU, the system is able to handle 1080p videos efficiently. Let's hope that comes to the most of the newer Macs with Snow Leopard (10.6).

RAM and other factors are generally a non-issue.

 

I'm having the same problem ever since I upgraded to 10.5.6. I reinstalled QuickTime and that helped for a while but it's choppy again. No problems with VLC.

I think the problem relates to the windowserver process. I noticed that whenever it spikes up to 10% CPU that's when QuickTime starts giving me grief. I hope Apple comes up with a resolution soon.

 

i had problems and i realized that the video was encoded on apple's pixlet video codec... had to compress it with sorenson squeeze and the playback was normal.