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Old 3rd December 2019, 18:14   #29021  |  Link
jdobbs
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Thought I'd share an interesting point I discovered. I recently got a UHD television and have been experimenting with playback with different 2160p files. Then I decided to disable 4K upscaling on my Sony UBP-X800 so I could make sure I am really getting UHD.

I was a little shocked to find that many of the reencoded UHD MKV/MP4 files weren't actually playing in UHD -- they were playing in 1080p and were being upscaled. Some experimenting showed that only the files I'd reencoded with BD-RB (ALTERNATE mode), or original BD files, were actually playing in true 2160p. My guess is that the player requires the files to be encoded with settings that are uhd-bd compatible (which BD-RB does via X265) and many downloads are not encoded that way.

Just thought I'd pass that on as food for thought. It may be peculiar to my player, I don't know, but I think there are possibly people out there who think they are getting 2160p output when they are actually only getting 1080p upscaled to 2160p on reencoded MKV/MP4 UHD files.
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Old 3rd December 2019, 18:23   #29022  |  Link
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Sometimes the gains are even bigger. Going from an 8 core Ryzen 1700x to a 12 core Ryzen 3900 I got a 2X speed boost with only 50% more cores, something to do with optimizations for AVX instruction sets.
That's pretty cool.
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Old 3rd December 2019, 19:53   #29023  |  Link
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Thanks jdobbs & Ch3vr0n ;-)
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Old 4th December 2019, 07:37   #29024  |  Link
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Originally Posted by jdobbs View Post
[...]but I think there are possibly people out there who think they are getting 2160p output when they are actually only getting 1080p upscaled to 2160p on downloaded UHD files.
Are you saying that some 2160p files are being reduced to 1080p by your player before being sent to the display? If so, that player, IMHO, is seriously flawed.
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Old 4th December 2019, 11:22   #29025  |  Link
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I rebuilt a concert blu-ray which had 720 x 480i mpeg 2 source with a 16:9 display aspect ratio. I noticed that the rebuilt version has small black bars at the top and bottom and the picture was of reduced height (slightly squashed) compared to the original. When I used the hidden option show_encoder=1, x264 reported the following: "lav [info]: 720x480i 32:27 @ 30000/101 fps (cfr)"
I could see that bd-rb was then telling x264 to use SAR=40/33 when doing the re-code, which I believe is the cause of this problem. Is there a way of forcing bd-rb to preserve the original SAR value?
Is your source a DVD? 32:27 = 1.1852 is the 'Generic' PAR of anamorph 16:9 NTSC DVDs. It is an assumption because the true PAR of DVDs/mpeg2 cannot be read from the video stream. The DVD could also have been authored using the ITU PAR of 1.212954 for 16:9. We simply don't know.
BD-RB uses the mpeg4 SAR of 40:33 = 1.212121... for x264 16:9 anamorph 720x480 encoding. It is AVC/mpeg4/blu-ray compliant and a very close approximation to the ITU PAR of 1.212945, but exhibits the well known aspect ratio difference of 2.3% compared to the 'Generic' PAR of 1.1852. This slight difference is normally not even noticed. As far as I remember you can't change the SAR in BD-RB to avoid non-compliant mpeg4/AVC video.

Thinking about it and hoping I remembered all this correctly, I am now wondering why BD-RB added top and bottom borders rather than left and right 8 pixels each. Did your original already come with any borders? Did you resize? What is your playback scenario? Does your player/TV add the top/bottom borders rather than BD-RB? Does your player read the SAR or force 16:9 DAR playback?
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Old 4th December 2019, 12:37   #29026  |  Link
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Originally Posted by jdobbs View Post
Thought I'd share an interesting point I discovered. I recently got a UHD television and have been experimenting with playback with different 2160p files. Then I decided to disable 4K upscaling on my Sony UBP-X800 so I could make sure I am really getting UHD.

I was a little shocked to find that many of the reencoded MKV/MP4 UHD files weren't actually playing in UHD -- they were playing in 1080p and were being upscaled. Some experimenting showed that only the files I'd reencoded with BD-RB (ALTERNATE mode), or original BD files, were actually playing in true 2160p. My guess is that the player requires the files to be encoded with settings that are uhd-bd compatible (which BD-RB does via X265) and many downloads are not encoded that way.

Just thought I'd pass that on as food for thought. It may be peculiar to my player, I don't know, but I think there are possibly people out there who think they are getting 2160p output when they are actually only getting 1080p upscaled to 2160p on reencoded MKV/MP4 UHD files.
what does mediainfo say about the file you are trying to play ? does it report the file as 1080p ??
also what is the file size of said 2160p file ?

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Old 4th December 2019, 15:31   #29027  |  Link
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Are you saying that some 2160p files are being reduced to 1080p by your player before being sent to the display? If so, that player, IMHO, is seriously flawed.
I'd say it's more likely that the source is seriously flawed. Players have built-in downscaling to cover being attached to non-UHD monitors and other non-compliance issues.
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Old 4th December 2019, 15:35   #29028  |  Link
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what does mediainfo say about the file you are trying to play ? does it report the file as 1080p ??
also what is the file size of said 2160p file ?
No. It is UHD. But, some of them, at least, aren't 3840x2160. For example one that I'm looking at now is 3840x1600. So there may be more to it than just the encoding parameters.

[Edit] In fact, several of the files I've looked at (that I had previously tested) are actually 3840x1600, which seems to be a fairly common format for reencoded MKV/MP4 files (even though the file title says "2160p"). In the end it may turn out to be the non-compliant sizing that is the real issue. But the original point is still valid. People may think they are watching these in UHD when they are actually simply watching an upscaled representation of it from a picture that was downscaled to 1080p. I know that is true at least on my Sony player, I can't speak for other units.
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Old 4th December 2019, 15:52   #29029  |  Link
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... People may think they are watching these in UHD when they are actually simply watching an upscaled representation of it from a picture that was downscaled to 1080p.....
LOL, who cares as long as people are happy with placebos
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Old 4th December 2019, 17:20   #29030  |  Link
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Placebos work. That's the reason so many "natural cures" are sold.

I'll take of a couple of these and reencode them with the borders that bring it up to 2160. I suspect that will fix the issue.

I have to say... I'm pretty impressed with the UHD blu-rays I've been watching since getting my UHD TV. It's more noticable than I thought it would be (on some discs, not all). Some of the reviews I read say that most people won't see the difference between HD and UHD from a normal viewing distance. But to me it looks more crisp (from about 10 feet where I usually watch).

But then again... there's always the placebo effect.
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Old 4th December 2019, 17:25   #29031  |  Link
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NIn fact, several of the files I've looked at (that I had previously tested) are actually 3840x1600, which seems to be a fairly common format for reencoded files (even though the file title says "2160p").
Well, that explains it. Many of the groups have it in their little heads that removing the letterbox bars from widescreen videos will reduce the file size. While it is true that it will, it obviously causes issues like this.

If I play a MKV file thru my Samsung and if it is 1920x800, the player will add the letterbox bars. But, if I author the file onto a BD, the player will vertically expand the video to fill the screen. Those cropped videos are a PITA.
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Old 4th December 2019, 19:20   #29032  |  Link
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If I play a MKV file thru my Samsung and if it is 1920x800, the player will add the letterbox bars. But, if I author the file onto a BD, the player will vertically expand the video to fill the screen. Those cropped videos are a PITA.
Indeed.... It's a shame that the Blu-ray 'HD' disc format does not support 'cropped' video. And even a bigger shame that the Blu-ray 'UHD' disc format followed suit
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Old 4th December 2019, 20:40   #29033  |  Link
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I have to say... I'm pretty impressed with the UHD blu-rays I've been watching since getting my UHD TV. It's more noticable than I thought it would be (on some discs, not all). Some of the reviews I read say that most people won't see the difference between HD and UHD from a normal viewing distance. But to me it looks more crisp (from about 10 feet where I usually watch).
I totally agree... I had an UHD TV before, but with the new one UHD sources look even better ... WAY better. You can already see it during the first few seconds when the Warner Bros Logo turns up, for example.
And at 5 feet even the blindest will see a difference
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Old 5th December 2019, 22:28   #29034  |  Link
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I'll take of a couple of these and reencode them with the borders that bring it up to 2160. I suspect that will fix the issue.

How do you do that?
Adding "black bars" to cropped videos?

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Old Yesterday, 01:12   #29035  |  Link
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How do you do that?
Adding "black bars" to cropped videos?
With AVISynth and one of the many available plugins that do many different kinds of video processing.
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Old Yesterday, 01:39   #29036  |  Link
jdobbs
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How do you do that?
Adding "black bars" to cropped videos?
Use BD-RB to import and reencode. It adds them automatically.
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Old Yesterday, 11:55   #29037  |  Link
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Use BD-RB to import and reencode. It adds them automatically.
Thanks.
And use alternate output?
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Old Yesterday, 20:07   #29038  |  Link
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Just reencode an 1920x808 file an the result was 1920x1080. Thanks jdobbs.
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Old Today, 04:49   #29039  |  Link
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Originally Posted by Sharc View Post
Is your source a DVD? 32:27 = 1.1852 is the 'Generic' PAR of anamorph 16:9 NTSC DVDs. It is an assumption because the true PAR of DVDs/mpeg2 cannot be read from the video stream. The DVD could also have been authored using the ITU PAR of 1.212954 for 16:9. We simply don't know.
BD-RB uses the mpeg4 SAR of 40:33 = 1.212121... for x264 16:9 anamorph 720x480 encoding. It is AVC/mpeg4/blu-ray compliant and a very close approximation to the ITU PAR of 1.212945, but exhibits the well known aspect ratio difference of 2.3% compared to the 'Generic' PAR of 1.1852. This slight difference is normally not even noticed. As far as I remember you can't change the SAR in BD-RB to avoid non-compliant mpeg4/AVC video.

Thinking about it and hoping I remembered all this correctly, I am now wondering why BD-RB added top and bottom borders rather than left and right 8 pixels each. Did your original already come with any borders? Did you resize? What is your playback scenario? Does your player/TV add the top/bottom borders rather than BD-RB? Does your player read the SAR or force 16:9 DAR playback?
Thanks for replying, Sharc. The source was "Out of Season" by the band Marillion. It's a triple disc set which was originally released on DVD, but now is out on Blu-Ray to take advantage of the higher quality sound. The small black bars only appeared on the rebuilt copy. Funnily enough I did try upscaling to 1080 and found there were no black bars. But this introduced a different problem: When using the pop-up menu, if I hovered the mouse over a chapter near the top of the page, it highlighted and activated one several lines below!
So I decided to keep it at 720x480, but the only way I could get a perfect copy was to grab the output of lastcmd.txt after each pass and manually recode each affected file in x264 replacing --sar 40:33 with --sar 32:27, then remuxing to m2ts myself. I then replaced the files created by BDRB with my own, which obviously broke the chapters. I fixed this by getting BDRB to rebuild the copy containing the replaced files, this time with no encoding of the video (as the file sizes were now correct for BD25). All menus and chapters work fine and the video is identical to the original. I've no idea if the new copy is blu-ray compliant, but it works perfectly on both the PS4 and in J River media centre. Obviously this was a very laborious way of doing a 3 disc set, but I could find no other method, and wondered if I could have done anything to make BDRB work automatically with these discs.
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