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  1. As PCs are started fading, and mobile devices are started taking over, I recently purchased a Samsung GALAXY Tab2 10.1 with following specs:

    Display
    -10.1" widescreen
    -1280x800 TFT

    Video
    Playback/ Recording: Full HD 1080p@30fps, HD@30fps

    Would it be sufficient to watch 4K (3840x2160p) videos?
    Last edited by enim; 4th Feb 2014 at 04:17.
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  2. Member Atak_Snajpera's Avatar
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    Really? 2160p video on 800p screen? It does not make sense at all. Besides I do not think that this toy will be able to decode 2160p HEVC
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  3. why not?
    I am wondering, How can it's 800p display can play 1080p videos? May be down scaling?
    I can appreciate more explanation, and...
    I would like to see some convincing concrete math here.

    -OR-
    What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?

    I had gone for 10.1" tablet b'coz any bigger tablet than this one is nothing but stupidity, as I already have most powerful laptop as a portable - mobile device atm.
    Last edited by enim; 4th Feb 2014 at 04:21.
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  4. My guess:
    - for UHD HEVC the tablet simply lacks the processing power for decoding (decoding and downsizing required)
    - UHD AVC might be possible depending on the cpu power and/or the hardware H.264 decoder chip
    Since you have a tablet how about simply testing and reporting back how it went?
    Simply upscaling a FullHD video and reencoding it to UHD should be a problem.
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  5. Originally posted by Atak_Snajpera
    Besides I do not think that this toy will be able to decode 2160p HEVC.
    Originally posted by Selur
    - for UHD HEVC the tablet simply lacks the processing power for decoding (decoding and downsizing required)
    - UHD AVC might be possible depending on the cpu power and/or the hardware H.264 decoder chip
    HEVC decoding is another issue to be considered seriously. Hopefully, it will be taken care by power processor chip and HEVC/H265/H264 decoder chip in unknown future.

    still I would ask...
    What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?
    I would like to see some convincing concrete math here.
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  6. What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?
    • there is no bare minimum resolution (other than 2x2) to display progressive MPEG-4 video, you can always scale down to the resolution of your display
    • the only thing I can think of which might be interesting is a minimum resolution which is required to see a difference between 4k and lower resolutions
      When you resize from 3840x2160 to 1280x720 you reduce the vertical and horizontal resolution each by a factor of 3, so you only have 1/9th of the pixels left. Depending on the quality of the resizer you will also loose quite a bit due additional to resizing artifacts.
      Speaking in SD terms, it's like watching a 720x480 clip on a 240x160 display.
      -> Will you see better quality if you watch a UHD or a full HD clip on a 720p screen? I would say it depends: a. on the used resizer (artifacts? gamma aware?) b. on the content itself. Do I think it will be a quality improvement which might be worth the additional processing power: No.

    I would like to see some convincing concrete math here.
    At least to me, it's not clear what that math should show.

    Cu Selur
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  7. Originally posted by Selur
    - for UHD HEVC the tablet simply lacks the processing power for decoding (decoding and downsizing required)
    - UHD AVC might be possible depending on the cpu power and/or the hardware H.264 decoder chip

    What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?
    there is no bare minimum resolution (other than 2x2) to display progressive MPEG-4 video, you can always scale down to the resolution of your display
    Whenever downscaling is required, fossking discarded DualCore also performs far better than expectations. I guess, discarded DualCore also have sufficient power to decode at-least 1080p HEVC.

    still I would ask...
    What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?
    I mean without DownScaling.

    I would like to see some convincing concrete math here. Developers are Well-come!
    There is some definite and finite math regarding PD - Pixel Density and Screen Size - without Down-Scaling.

    Just, now my better half asked me very polite and sweet,
    Honey, How about another Benz? I replied this time no more Benz, I have some French connections for 155m Howitzer too! I am still figuring out to save my ssa, just in case.
    Last edited by enim; 4th Feb 2014 at 05:15.
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  8. What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?
    Like I wrote before: 2x2 pixels, is the minimum resolution to display in progressive Yv12 content, since every video content can be downscaled to that resolution.

    If you want the math to calculate depending of the resolution if you could see the difference between a UHD and a 720p screen you might want to look at http://carltonbale.com/does-4k-resolution-matter/ and the corresponding excel sheet.

    -> Since I assume that either you are just trolling or we are simply talking past each other, I excuse myself from this thread, since for me it doesn't seem to have a point.

    If the question really was: would a 720p screen be able to display the full potential of UHD content, the answer is no, simply because you throw away 8/9th of all pixels.
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  9. Member Atak_Snajpera's Avatar
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    What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?
    It all depends how far you will be sitting from display. For example oculus rift (first prototype) has 1280x720 screen and it looks really bad(massive pixelation). However regular tv with the same resolution looks ok because you normally watch tv from certain distance (let's say 2m - 3m)
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  10. Yup:
    a. to see the full potential of a video with the resolution XxY your display at least needs to have the same resolution.
    (otherwise you are loosing pixel which always means you potentially loose information)
    b. if you are farther away from the display the calculations I linked to above (post #8) are interesting
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  11. Pixel Per Inch PPI = SQRT(w^2+h^2)/di
    where w is width resolution in pixel.
    h is height resolution in pixel.
    di is diagonal size in inch.
    at 96dpi screen size comes to 45.893899 inches.
    at 75dpi screen size comes to 58.744191 inches.

    It is no longer that I can carry at all.

    When it comes finally to down scaling, i do not see any naked eyes difference between 720p and 1080p on 10.1" inch tablet, and I do not care the differences seen by software analysis. -or- may be I can notice some minute differences, if I can find technology to get into the inside of tablet and watch the screen from the back.

    I just called my French connections - a friends, and they already shipped it 155mm already.


    ---------------------------------------------------------------------------------------------------------------------------------------------
    When it comes to video, there are tons of goofs and bloops.... OOOoooppps!
    Last edited by enim; 4th Feb 2014 at 06:05.
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  12. Ah, what you are looking for might be http://www.scss.com.au/family/andrew/camera/resolution
    btw. your Samsung GALAXY Tab2 with 10.1" and 720p should have 145 dpi.
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  13. your Samsung GALAXY Tab2 with 10.1" and 720p should have 145 dpi.
    For 4K (3840x2160p) contents it comes to 436.2192dpi approximately, I doubt that tablet cpu can ever process 436.2192dpi in next 20 years to come without down scaling. and, by that time tablet might be faded by some other new techno invention.

    My better half just said that fossking tablet will be returned tomorrow.
    Last edited by enim; 4th Feb 2014 at 06:23.
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  14. Member Atak_Snajpera's Avatar
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    Today's high-end smartphones have already 1440p screens with enough cpu power. (http://www.digitaltrends.com/mobile/vivo-xplay-3s-launched-with-worlds-first-1440p-sma...phone-display/) In 2015 probably we will even see 2160p displays in 5''
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  15. It would be really awesome to watch 4K videos on 4 inch screen.
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  16. yup, 437dpi definitly isn't the problem, 25601440 in 5.5" (534dpi) is already possible:
    To put that into perspective, the human-perceptible limit at a 12-inch distance is only around 300 PPI. That's not to say anything above 300 is a waste; hold the phone closer and you'll need a higher PPI to see an unpixelated image. 538 PPI, however, is just insane.
    source: http://arstechnica.com/gadgets/2013/08/smartphone-display-wars-go-to-ludicrous-speed-2...in-5-5-inches/
    and simply not on the market.
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  17. Thanks to Atak & Selur for informative links, which led me in other directions of some fine tunning. I will check in details and see if it works.
    I hope for the best.

    Thanx!
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  18. It is all about power,..., so far:

    Samsung Galaxy Note 10.1 will play 4k video with MX player. I decoded 4k from Sony FDR AX1 original footage, 3840x2160 with x264, settings on default, ref 3, I got average 34Mbit bitrate, peak something over 40Mbit but I think set buffer to about that limit. It played the video but it was stuttering, that stutter makes it unwatchable, something like 3-5 frames per second.

    Original was a bit harder to play. With streaming you cut down another frame or two per second.
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  19. It played the video but it was stuttering, that stutter makes it unwatchable, something like 3-5 frames per second.
    I ran into same problem while trying to play very High-Q 4K sample. At present Galaxy specs are under:

    Display
    -10.1" widescreen
    -1280x800 TFT
    -150 PPI

    As I stated before it requires 436.2192 PPI instead of 150 PPI plus powerful processor with very large amount of memory, and ofcource powerful and efficient decoder chip.
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  20. Yes,
    but I'm not sure how resolution has much to do with it, except that it is harder to decode. Any player is just an app that is trying to play video and render it on screen. It will make it in time or it will not. And that app will support that high resolution or not. So it is more like what app will do thi and that, not model of that tablet. There is no watchdog that will halt playback because of resolution or difficult profile, it just depends on app - player that does playback. Those little gadgets are becoming a computers, not narrow designed boxes.

    For example I was asked to check Hi10 profile playability so I might as well used it now for further explanation:
    players (apps) behave differently playing back Hi10, HD and SD (mind you easy settings no that crazy settings you might find on web). One might try that build in video player and say , Samsung Galaxy Note 10.1 does not support Hi10 profile. But, MX player manages, with a bug, nevertheless it will play it. SD version OK, HD heavy stutter, but both with a bug that creates artifacts in picture, in highlights. VLC played SD Hi10 resolution OK, so one might enjoy SD Hi10 and will say Samsung Galaxy Note 10.1 supports Hi10 video . But trying to play Hi10 HD video , it will freeze.

    Now, that model is one year old, so it might be even other story with latest model. I think personally it is kind of nightmare a bit if shopping to figure out what year model it is what. A price might give you a hinch but anyway ...
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  21. I guess, latest is Tab Pro 12.2" with quad core with 247.4486 PPI, still there is a long long way to go!
    Processing Power, Amount of Memory, and Decoder Capacity play vital role for smooth playback of any video.
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  22. Member
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    It makes no fakking sense to ask the question " What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?" phrased in that way. I've seen stuff where they actually did crunch the numbers, and it's completely meaningless to as that without considering the viewing distance.

    With 1080p video, at the median viewing distance of 9 feet, and with normal 20/20 vision, you need at least a 70" screen to be able to actually see all the detail.

    With 2160p I forget what the screen size is exactly (should have bookmarked it), but it was much, much bigger. It'd take up most of the wall.

    I don't think you'd be able to see the detail on a 10 inch screen even with your nose pressed against it.

    And as others said, it's silly to even think such a machine would play it passably anyway.
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  23. Member
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    Originally Posted by Hoser Rob View Post
    It makes no fakking sense to ask the question " What would be the bare minimum screen size for viewing true 4K (3840x2160p) videos?" phrased in that way. I've seen stuff where they actually did crunch the numbers, and it's completely meaningless to as that without considering the viewing distance.

    With 1080p video, at the median viewing distance of 9 feet, and with normal 20/20 vision, you need at least a 70" screen to be able to actually see all the detail.

    With 2160p I forget what the screen size is exactly (should have bookmarked it), but it was much, much bigger. It'd take up most of the wall.

    I don't think you'd be able to see the detail on a 10 inch screen even with your nose pressed against it.
    I don't think the point is to see "all the detail". I'm guessing that enim has techno lust and rather than accepting the reality that 4k is too pricy at this time, he's trying to get into it on the cheap via a tablet without realizing that currently this is not an option.
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  24. HoserRob - That oled display on 4k camcorder (well I presume it is oled) has no 4k resolution or has it? So like that camcorder display that tablet is just meant to play it. It makes little sense to render 4k on 10". But I'm sure it will be crucial point of propaganda to sell 2015 Apple iPad.
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  25. Originally posted by Hoser Rob
    I've seen stuff where they actually did crunch the numbers, and it's completely meaningless to as that without considering the viewing distance.

    With 1080p video, at the median viewing distance of 9 feet, and with normal 20/20 vision, you need at least a 70" screen to be able to actually see all the detail.

    I don't think you'd be able to see the detail on a 10 inch screen even with your nose pressed against it.

    it's silly to even think such a machine [EXPENSIVE TOYS] would play it passably anyway.


    Originally posted by jman98
    I don't think the point is to see "all the detail".

    Originally posted by _AL_
    It makes little sense to render 4k on 10". But I'm sure it will be crucial point of propaganda to sell 2015 Apple iPad.
    -Concluded!

    Tks everyone.
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