screen resolution

Question

Level 1

63 points

screen resolution

Hi,

I've been meaning to check here about this for a while now. I noticed a big difference in video quality when I saw both a DVD and an iTunes TV show played on my sister MacBook compared to my iMac.
They both play crystal clear on the MacBook, but the video is grainy on my iMac.
Any ideas?

Thanks.

iMac G4, Mac OS X (10.4.11), 2.16 GHz Intel Core 2 Duo

Posted on Dec 5, 2008 1:45 PM

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Answer 1

Dec 5, 2008 3:22 PM in response to NeddySeagoon

What size is your iMac's screen (in inches) and what resolution are you using (in System Preferences Displays pane)?

For the iMac's built-in screen, the native resolution should be the one at the bottom of the list (the highest one). If you have a lower resolution selected, it will not be as sharp.

Also, since the iMac's screen is physically larger with more pixels, it may look more "grainy" simply because the image is blown up to a larger size.

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Answer 2

NeddySeagoon Author

Level 1

63 points

Dec 5, 2008 4:17 PM in response to NeddySeagoon

Thanks for the response.

In System Preferences/Display COLOR is set to iMac and DISPLAY is 1680 x 1050.

The screen size is 20 inches.

Cheers.

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Answer 3

Dec 5, 2008 4:31 PM in response to NeddySeagoon

So, that is the optimum (native) resolution. My guess for your "issue" is that if you are displaying the video full screen, you are blowing up the video image to a much larger size in the iMac. Also, the MacBook pixels are smaller (more pixels per inch) compared to your iMac's screen.

Therefore, since the video has a fixed number of pixels, the same video file will look sharper on the MacBook screen, if using full screen on both Macs. For a fair comparison, view it at +Actual Size+ (under the View menu in most playback programs) on both Macs. It may still look a little smaller (and sharper) on the MacBook (because of the smaller pixels), but it should look mostly the same on both Macs.

If that's not the case, something else is going on. Please post back.

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Answer 4

NeddySeagoon Author

Level 1

63 points

Dec 5, 2008 4:53 PM in response to Kenichi Watanabe

Yes. that would explain an iTunes video. (would the HD version of a show improve that?)

But a DVD is meant for playback on a mucher larger screen than an iMac.

Thanks.

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Answer 5

Dec 5, 2008 5:16 PM in response to NeddySeagoon

A DVD is higher res than standard def, but it's not high def (HD). Just do a +View - Actual Size+ in DVD Player while playing the DVD on your iMac, and that's how many pixels it really takes (probably about one-quarter of your screen).

Some HDTV's may have much larger screen size, but the pixels are also bigger. A high-end "1080p" HDTV has a resolution of 1920×1080, even if it has a 52-inch screen. Your 20-inch iMac screen at 1680x1050 almost has as many pixels. Plus modern DVD players and HDTV's use other tricks to make the image look sharper.

If you downloaded an HD video file, it will definitely make a difference. You can use Apple's QuickTime movie trailers web site to try it out.

http://www.apple.com/trailers/

Note: The 720p files download much faster than the 1080p files, and look almost as good on my iMac's screen when you give the +full screen+ command.

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Answer 6

NeddySeagoon Author

Level 1

63 points

Dec 5, 2008 6:41 PM in response to Kenichi Watanabe

Hi again,

actually the HD trailers were one of the things bothering me because whether at fullscreen or half size they look much better than the iTunes shows. Is this because they are made for an iMac (so to speak) and the videos on iTunes are intended for iPods?? But I just put the HD STAR TREK trailer next to some iTunes vids and put both to half size and they both had perfect video quality.
To be honest I would have said my iTunes was perfect on full screen prior to seeing them on the MacBook. I probably am just nit picking.
Been a while since I watched a DVD on the Mac aso I'll check one out tomorrow.
But there are SD and HD versions of some shows on iTunes now. I read that if you purchase the HD version that both HD and SD download simultaneously. The SD is meant for iPod and the HD version is meant for Mac and Apple TV. So does that mean that the HD will look better in full screen mode?

Thanks for taking the time to answer all this.

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Answer 7

Dec 5, 2008 7:16 PM in response to NeddySeagoon

iTunes uses QuickTime, so the same content should look identical.

HD is much higher resolution than +iPod resolution+. The max resolution playable on an iPod is 640x480. It may even be lower for a particular download, because a typical iPod screen is only at 320x240, I believe. So if you download something that is at "iPod" resolution, it may really be low res compared to something that is HD. HD can be as high as 1920x1080.

The standard def shows and movies downloaded through the iTunes Store is typically 640x480. An iPod can play that resolution. If you want to look at something that is HD and free in iTunes, there are quite a few HD podcasts that you can download at no cost.

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