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Patbil10

macrumors newbie
Original poster
Jan 19, 2015
27
0
Hi guys, I just got my new 5K iMac, (first ever since I've been a Windows PC guy forever) and I'm really loving it. You guys know where to download uncompressed 4K demo videos ?

The samples downloaded so far must have been compressed/modified because they look almost identical in quality when played on my PC. The monitor on the Windows system is a recent Dell IPS 23" with max resolution of 1920x1080.

Just not sure I've seen "real 4K" on my iMac yet...

Thanks :)
 

handsome pete

macrumors 68000
Aug 15, 2008
1,725
259
Hi guys, I just got my new 5K iMac, (first ever since I've been a Windows PC guy forever) and I'm really loving it. You guys know where to download uncompressed 4K demo videos ?

The samples downloaded so far must have been compressed/modified because they look almost identical in quality when played on my PC. The monitor on the Windows system is a recent Dell IPS 23" with max resolution of 1920x1080.

Just not sure I've seen "real 4K" on my iMac yet...

Thanks :)

Uncompressed? Are you sure you know what you're asking for with that?
 

Patbil10

macrumors newbie
Original poster
Jan 19, 2015
27
0
Uncompressed? Are you sure you know what you're asking for with that?

I'm asking for real 4K video that wasn't converted to lower res. Perhaps I'm not expressing myself correctly here.... if not, please enlighten me. :)
 

Nermal

Moderator
Staff member
Dec 7, 2002
20,664
4,086
New Zealand
Uncompressed 24-bit 4k is 637 MB/second, if I've done my calculations correctly. You don't want uncompressed, you just want "less compressed" :)

There is a (compressed) 3.75k copy of "Sintel" available here as a starting point (the 4.2 GB file).
 

Patbil10

macrumors newbie
Original poster
Jan 19, 2015
27
0
Uncompressed 24-bit 4k is 637 MB/second, if I've done my calculations correctly. You don't want uncompressed, you just want "less compressed" :)

There is a (compressed) 3.75k copy of "Sintel" available here as a starting point (the 4.2 GB file).

Thanks for explaining. :) Since I played the same "4K" vid sample on my Windows machine, I was a little surprised it looked that good. I was expecting a night/day difference in quality VS my new iMac.
 

handsome pete

macrumors 68000
Aug 15, 2008
1,725
259
I'm asking for real 4K video that wasn't converted to lower res. Perhaps I'm not expressing myself correctly here.... if not, please enlighten me. :)

Nermal pointed out the file size dilemma of uncompressed.

I think you're confusing compression with resolution. They are independent of each other.

Resolution is the size of your video (pixel width and height), with the common HD ones being 720, 1080, 2K, and 4K.

Compression is the process of decreasing a video's file size through algorithms that essentially remove detail that you don't really see anyway (to a certain degree). Obviously the more you compress, the more noticeable the quality drop gets. When talking compression, you're talking about different codecs (h264, mpeg4, proRes, etc.).

So when videos are often compressed, they can be downsampled (resolution-wise) as an additional step to decrease file size. But it's not what we usually think of when we talk about compression.
 

Patbil10

macrumors newbie
Original poster
Jan 19, 2015
27
0
Nermal pointed out the file size dilemma of uncompressed.

I think you're confusing compression with resolution. They are independent of each other.

Resolution is the size of your video (pixel width and height), with the common HD ones being 720, 1080, 2K, and 4K.

Compression is the process of decreasing a video's file size through algorithms that essentially remove detail that you don't really see anyway (to a certain degree). Obviously the more you compress, the more noticeable the quality drop gets. When talking compression, you're talking about different codecs (h264, mpeg4, proRes, etc.).

So when videos are often compressed, they can be downsampled (resolution-wise) as an additional step to decrease file size. But it's not what we usually think of when we talk about compression.

Wow ! Thanks, now I totally understand. I guess I'm looking for full res 4K to view on my iMac. :D Not easy to find.... :(
 

joema2

macrumors 68000
Sep 3, 2013
1,645
864
...looking for full res 4K to view on my iMac. :D Not easy to find.... :(

There is tons of 4k stuff on Vimeo, much of which can be downloaded. However I think you must sign up for Vimeo for 4k download. Here is one example:

https://vimeo.com/93003441

Vimeo just added 4k streaming but to enable this requires the content provider to re-upload their 4k material. I don't know how to identify those videos.

However here is one that is supposedly 4k streaming: https://vimeo.com/115541651
 
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