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iREZ · Feb 25, 2006, 09:12 PM

ok i know that the difference between the two computers is processor speed 1.83 vs 2.0 and screen size (HD space isn't a concern seeing how i have 400gb of external space). thing is that i have a dell 20" lcd and im wondering if it's better to get the 17" and span (already have the connector that came with my powerbook that is the same as the imac connector) on to my 20" monitor, or to sell the 20" LCD and get the 20" imac. I like having the Dell monitor because it has sooo many inputs, and will give me more screen space (2 screens vs 1), but my concern is if the 64mb of VRAM per screen can handle it enough to play videos without dropping framerates when i play vids ive made off handbrake. can anybody here who owns an intel imac with only 128mb of VRAM span and tell me if it's a concern worth debating over. id save myself about 400 bucks and id have a computer only .17x2mhz slower which seems like the better deal in the end. also is the mhz difference that huge? i know intel duo 2.0 is the min requirement for 1080 HD trailers but people have mentioned that the 17" can run the same trailers just as fine. thanks for your time.

mduell · Feb 25, 2006, 09:36 PM

VRAM and playing videos aren't related. Systems with 32MB VRAM and one screen can play videos.

I'd take the 17" and keep your 20".

Even my single 1.86 can play most 1080p trailers fine (in VLC, Quicktime for Windows is crap).

mavherzog · Feb 25, 2006, 09:53 PM

I LOVE desktop spanning...

(of course, I span my 20" iMac with a 21" CRT)

powerbook911 · Feb 26, 2006, 02:07 AM

I chose to keep my 20-inch ACD and get the 17-inch iMac. That way I was able to keep the ACD I love, but I can always sell the iMac to replace with anything I want.

iREZ · Feb 26, 2006, 11:15 AM

Originally Posted by mduell

VRAM and playing videos aren't related. Systems with 32MB VRAM and one screen can play videos.

aren't the new intel macs using more of the GPU when it comes to vids? im almost certain ive read this here somewhere on the forums. i guess ill wait till the 28th, and if nothing fantastic is released...ill go with the 17".

harrisjamieh · Feb 26, 2006, 11:50 AM

Ye the new intels partly (or fully, i cant remember) use the GPU for decoding HD content, hence they are very efficient at doing so. I'm not sure, however, if it also decodes standard video or not.

mduell · Feb 26, 2006, 02:34 PM

Originally Posted by iREZ

aren't the new intel macs using more of the GPU when it comes to vids? im almost certain ive read this here somewhere on the forums. i guess ill wait till the 28th, and if nothing fantastic is released...ill go with the 17".

The GPU in the Intel Macs can accelerate the playback of some video formats. However it depends on the driver supporting it, and I have yet to see any evidence that this is the case.

harrisjamieh · Feb 26, 2006, 04:34 PM

Originally Posted by mduell

The GPU in the Intel Macs can accelerate the playback of some video formats. However it depends on the driver supporting it, and I have yet to see any evidence that this is the case.

Surely evidence is an iMac CD being able to play 2-3 HD videos at the same time without using over 60-70% of the processor...

mduell · Feb 26, 2006, 05:24 PM

Originally Posted by harrisjamieh

Surely evidence is an iMac CD being able to play 2-3 HD videos at the same time without using over 60-70% of the processor...

Not evidence of GPU acceleration.

P · Feb 27, 2006, 11:36 AM

Originally Posted by mduell

Not evidence of GPU acceleration.

Really? You think the Core Duo can play 4 HD movies? Ah well, this press release indicates that the video is hardware accelerated. They talk about Avivo which is ATIs name for their acceleration hardware.

Eug Wanker · Feb 27, 2006, 12:24 PM

Originally Posted by harrisjamieh

Surely evidence is an iMac CD being able to play 2-3 HD videos at the same time without using over 60-70% of the processor...

What type of HD? 720p maybe, but not 1080p. You can only play one 1080p HD video at a time or you'll get dropped frames.

In fact, I have shown that one may get dropped frames playing even just one higher frame rate 30fps 1920x1080 video, although CPU speed doesn't seem to be the limiting factor here.

Originally Posted by P

Really? You think the Core Duo can play 4 HD movies? Ah well, this press release indicates that the video is hardware accelerated. They talk about Avivo which is ATIs name for their acceleration hardware.

It has already been confirmed that Apple does NOT currently use GPU acceleration for H.264 playback.

mduell · Feb 27, 2006, 01:15 PM

Originally Posted by P

Really? You think the Core Duo can play 4 HD movies? Ah well, this press release indicates that the video is hardware accelerated. They talk about Avivo which is ATIs name for their acceleration hardware.

Supporting AVIVO does not imply supporting H.264 acceleration. The first generation of the Windows drives for the X1xxx cards with AVIVO did not support H.264 acceleration. AFAIK it still requires a special WMP plugin on Windows for H.264 acceleration support.

Originally Posted by Eug Wanker

What type of HD? 720p maybe, but not 1080p. You can only play one 1080p HD video at a time or you'll get dropped frames.

In fact, I have shown that one may get dropped frames playing even just one higher frame rate 30fps 1920x1080 video, although CPU speed doesn't seem to be the limiting factor here.

People have reported (in one of the MWSF threads, I think) playing 2 and 3 1080p trailers from Apple's site without dropping frames.
What decoder profile does that 1080p/30fps video use? Whats the bitrate? If you use one of the higher complexity profiles and crank the bitrate up high enough, you can make any computer choke.

Eug Wanker · Feb 27, 2006, 02:52 PM

Originally Posted by mduell

People have reported (in one of the MWSF threads, I think) playing 2 and 3 1080p trailers from Apple's site without dropping frames.
What decoder profile does that 1080p/30fps video use? Whats the bitrate? If you use one of the higher complexity profiles and crank the bitrate up high enough, you can make any computer choke.

H.264 1920x1080 30 fps 8.75 Mbps. When played fullscreen, It doesn't choke on a Quad G5.

(Some of the other HD 1080p videos are something like 1920x816 24 fps, at say 8 Mbps.)

Personally, I think the 3x1080p posts are probably wrong. You can play more than one reduced rez 24 fps 1080p video at once, but only the less stressing parts of the video will play cleanly. I made a point of sitting through the entire video and watched for dropped frames. Furthermore, other people have already verified that even on 24 fps 1080p with reduced horizontal resolutions, at certain times during playback the CPU usage will be well over 100% (out of 200%), even if sometimes it's as low as 75% or whatever. Thus, 2 videos would be well over 200% at the more stressful times of the videos.

Also, the QT info window only shows the info for one QT video, not all three at the same time. ie. You can't watch the numerical frame rate info for 3 videos at the same time.

mduell · Feb 27, 2006, 05:23 PM

Originally Posted by Eug Wanker

H.264 1920x1080 30 fps 8.75 Mbps. When played fullscreen, It doesn't choke on a Quad G5.

(Some of the other HD 1080p videos are something like 1920x816 24 fps, at say 8 Mbps.)

Personally, I think the 3x1080p posts are probably wrong. You can play more than one reduced rez 24 fps 1080p video at once, but only the less stressing parts of the video will play cleanly. I made a point of sitting through the entire video and watched for dropped frames. Furthermore, other people have already verified that even on 24 fps 1080p with reduced horizontal resolutions, at certain times during playback the CPU usage will be well over 100% (out of 200%), even if sometimes it's as low as 75% or whatever. Thus, 2 videos would be well over 200% at the more stressful times of the videos.

Also, the QT info window only shows the info for one QT video, not all three at the same time. ie. You can't watch the numerical frame rate info for 3 videos at the same time.

Bitrate is independent of resolution and framerate.

Which media player were you using? On my Windows/PM box I can play movies flawlessly in VLC that Quicktime chokes and skips on.

Eug Wanker · Feb 28, 2006, 10:05 AM

Originally Posted by mduell

Bitrate is independent of resolution and framerate.

Yes I know. However, you asked what bitrate I was playing so I told you (along with the frame rate and resolution).

Which media player were you using? On my Windows/PM box I can play movies flawlessly in VLC that Quicktime chokes and skips on.

QuickTime 7

I'm not sure why you bring up QuickTime on Windows, since I was playing the stuff back only on Macs.

QuickTime on OS X ≠ QuickTime on Windows.

I generally don't use VLC on OS X, because it's got a clunky interface, and it's irrelevant to most people trying to playback QT video. I do keep it as a backup though.

iREZ · Mar 2, 2006, 10:16 PM

i bought the 17" iMac two days ago...i cant wait for this wed!!!