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MacOSXAddict
Mar 15, 2008, 02:51 PM
I have a 1.8Ghz Core Duo Mac mini with 2 GB of RAM. Recently bought a 40" HDTV and started to watch 720p TV shows on it.

The Mac mini plays the 720p perfectly but in some stages of the 720p (especially in fast moving scenes) the Mac mini begins to stutter the video playback.

Is anyone else having this issue?

Can one fix the stuttering? or is it just the fact that the hardware is being pushed to its limit.

Thanks,

Addict.



Cave Man
Mar 15, 2008, 03:32 PM
What codec is the video encoded in and what is its bitrate? The mini will handle MPEG-2 fine because the GMA950 has hardware acceleration for it built-in, but the does not do H.264 that is decoded by the cpu. A lot of factors go into this process.

hookem12387
Mar 15, 2008, 03:51 PM
On my 1.8 c2d I've never had a problem with any codec 720p video, just me, though.

MacOSXAddict
Mar 15, 2008, 04:33 PM
What codec is the video encoded in and what is its bitrate? The mini will handle MPEG-2 fine because the GMA950 has hardware acceleration for it built-in, but the does not do H.264 that is decoded by the cpu. A lot of factors go into this process.

Watching 720p H.264 videos.

Cave Man
Mar 15, 2008, 05:49 PM
Watching 720p H.264 videos.

How's the bitrate? You might be running up against that.

MacOSXAddict
Mar 15, 2008, 09:04 PM
Bitrate is 3658 kbits/s.........

Cave Man
Mar 15, 2008, 10:49 PM
Bitrate is 3658 kbits/s.........

That bitrate seems fine. The 720 trailers from Apple are routinely above 5000 kbs. Are they at 24 fps? What container are they in? My Mini (1.66 CD) handles the Apple 720 trailers just fine. I'm not sure why yours is having trouble. Does Activity Monitor show any unusual activity by some other app that may be stalling your computer?

MacOSXAddict
Mar 15, 2008, 10:55 PM
That bitrate seems fine. The 720 trailers from Apple are routinely above 5000 kbs. Are they at 24 fps? What container are they in? My Mini (1.66 CD) handles the Apple 720 trailers just fine. I'm not sure why yours is having trouble. Does Activity Monitor show any unusual activity by some other app that may be stalling your computer?

The video files I am using were originally .mkv files. I "save as" and save them as a self-contained movie to make them Quicktime files. The Apple trailers play fine. It is just the mkv files saved as Quicktime files that stutter during fast motion.

Cave Man
Mar 15, 2008, 11:36 PM
The video files I am using were originally .mkv files. I "save as" and save them as a self-contained movie to make them Quicktime files. The Apple trailers play fine. It is just the mkv files saved as Quicktime files that stutter during fast motion.

Hmm. Were these videos encoded with variable bitrate? It may be that during these scenes the bitrate goes sky-high (e.g., 8000 kbps), which could cause such stuttering. I generally encode mine at constant bit rates (which pays a price on fast moving scenes). Can you try this video on a MacBook Pro or similar such machine that has hardware decoding of H.264? I think that would answer the question if it's a bitrate issue on these scenes.