[asiajason]

I have a new iMac and 720p .mkv files on a local USB drive are still stuttering for me on my external TV @ 60hz.

Can anyone give me help? I've posted what you asked for below. The Debug.log consists of starting up xbmc and watching that .mkv for 30 seconds or so. I see I'm consistenly getting 60fps in the debug window, but it drops to 50 fps or so when the scene pans, and thats when it stutters.

Also, the TV is connected via HDMI -> display port (now also the thunderbolt port)

Debug.log
media.info

XBMC: 10.1 (Git-e9e9099)
iMac: 2.5 GHz i5 4GB 1333 Mhz DDR3 OSX 10.6.8
Monitors / GPU data:

AMD Radeon HD 6750M:

Chipset Model: AMD Radeon HD 6750M
Type: GPU
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 512 MB
Vendor: ATI (0x1002)
Device ID: 0x6741
Revision ID: 0x0000
ROM Revision: 113-C2950H-170
EFI Driver Version: 01.00.544

Displays:

iMac:
Resolution: 1920 x 1080
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Built-In: Yes
Connection Type: DisplayPort

KONKA LCDTV:
Resolution: 1600 x 900 @ 60 Hz
Pixel Depth: 32-Bit Color (ARGB8888)
Mirror: Off
Online: Yes
Rotation: Supported
Television: Yes
Display Connector:
Status: No Display Connected
Display Connector:
Status: No Display Connected

[Ned Scott]

I recall there being some weirdness with the GPU decoding with the new Mac Minis that was causing playback to stutter when it shouldn't. I wonder if the iMac is having the same issue. A temp work around would be to go into XBMC's Settings -> Videos -> Playback and disable hardware acceleration. The CPU is far more than enough to handle all the video decoding, so technically it doesn't matter if the video decoding is going through the GPU or CPU.

Hopefully your information and the information in the MacMini thread will shed some light on this. I get the feeling an update for Mac OS X might be needed. 10.7.1 is already out, and 10.7.2 is being tested by developers.

[asiajason]

Ned, thanks for the info.

My hardware acceleration was actually off, and when I tried it on, it was way worse.

As far as an update, I'm still on 10.6.8, not 10.7.

Do you mean to imply it's not xbmc's problem?

[davilla]

I suggest grabbing a nightly,

Mar 9 2011 (Git:e9e9099) is pretty old now.

DEBUG: ReadEditDecisionLists - Assuming NTSC or 60i interlaced content. Adjusted frames per second from 59.940 (~59.940 fps) to 29.970

[asiajason]

DEBUG: ReadEditDecisionLists - Assuming NTSC or 60i interlaced content. Adjusted frames per second from 59.940 (~59.940 fps) to 29.970

what is this?

this makes me think of another question: I'm in Hong Kong, so my mac and tv I assume is running @50hz, but the shows recorded are 30fps - does this have any effect? I seriously doubt it, as there are other freq's working just fine in both, but I thought I'd mention it.

[asiajason]

I suggest grabbing a nightly,

At first, it seems to be better... not skipping in the same full screen panning places, but it is still video lagging in some weird (no action) places now...

But then I started trying the other settings, like render method, and allow hardware acc... and all were worse, so after switching them back (render: auto; hardware acc: off) now things are TERRIBLE - as if the hardware acc is still on.

Something "stuck", it seems the hardware acceleration "stuck" on....

Please help, now shows are UNWATCHABLE!

[asiajason]

new debug.log

[neurosis13]

play the movie, press "M" , in the menue go to video and change the "video scaling method" and see which works best for you.
Might be "nearest neighbour"