Playback of 1080p HD movies on iMac

I don't necessarily know the answer, but I know that on my macbook there have been a few times where it's taken up my CPU. I'd probably guess (I know you're not looking for a guess, but this is what I've always thought and would like to be proven wrong/right) that it mostly depends on RAM and graphics card.

CPU does most of the work so invest on good CPU.

Hellhammer said:

CPU does most of the work so invest on good CPU.

Click to expand...

On my PC my cpu couldn't handle large HD files but then i got a movie player that offloaded the work to my graphics card. My media centre pc with xbmc does the same. Can this also be done in mac os?

thedon1 said:

On my PC my cpu couldn't handle large HD files but then i got a movie player that offloaded the work to my graphics card. My media centre pc with xbmc does the same. Can this also be done in mac os?

Click to expand...

AFAIK, only 9400M, 320M, 9600M and 330M are supported so far, so no, you can't in iMac. In the future it may happen though

hleewell said:

Which of the following is most essential in playing back 1080p HD movies using apps like VLC or Plex :

Clock Speed important
Multi Core important
RAM not so important
Graphic card+VRAM gpu important for some, vRAM no so much
Speed of HDD (SSD vs HDD?) unimportant

Click to expand...

If the video is encoded in h.264 and in the appropriate container (e.g., m4v) then Plex can use gpu decoding on 9400m and above gpus so long as you have 10.6.3 or higher installed. I'd forego VLC in favor of MPlayer Extended.

Any of the Macs sold today can play 1080p video from Blu-ray rips provided the audio is not HD (i.e., True-HD or DTS-MA). Decoding the video while simultaneously extracting the 5.1 audio cores from the HD audio tracks is pretty taxing on the low-end Macs.

For macs, the most important component for playback is going to be the CPU. There are a lot of GPU/hardware acceleration options on Windows and Linux but not on OSX. As far as I know, Plex is the only program that can utilize the GPU, but you must have an nVidia 9400m, 320m, or 330m chip http://elan.plexapp.com/2010/04/27/hardware-accelerated-h-264-decoding-on-plex/. With that said, my 3.06GHz C2D iMac plays back all 1080p just fine, even for videos with karaoke-styled subtitles, which often give computers a hard time. Doesn't QuickTime also have acceleration? Too bad QT is horribly slow with huge .mkv files. I find MPlayer OSX Extended to be the best player for CPU usage and is incredibly quick at seeking (.mkvs). I don't use .mp4 files, so I'm not sure about them.

steveotron said:

There are a lot of GPU/hardware acceleration options on Windows and Linux but not on OSX. As far as I know, Plex is the only program that can utilize the GPU, but you must have an nVidia 9400m, 320m, or 330m chip.

Click to expand...

XBMC, Plex and Quicktime all do h.264 gpu hardware decoding with 10.6.3 or higher, provided they're in the right containers.

steveotron said:

...Doesn't QuickTime also have acceleration? Too bad QT is horribly slow with huge .mkv files...

Click to expand...

Yes QT does have acceleration as well. And the reason QT is slow when processing MKV container videos is because they require a third-party codec.

Oh, and for the people using Plex, you might want to reset your audio settings in Audio Midi Setup. Default settings for Output shoudl be 44100.0 Hz and 2ch-24bit, but when you start up Plex, it cchanges them to 48,000.0 Hz and 2ch-16bit and doesn't revert them once the program closes. Probably won't notice it but it sort of bugs me that it would do that.