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Old 4th December 2019, 11:22   #29021  |  Link
Sharc
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Originally Posted by Alleycat View Post
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   #29022  |  Link
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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 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 ?

Last edited by jdobbs; 7th December 2019 at 15:26.
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Old 4th December 2019, 15:31   #29023  |  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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Last edited by jdobbs; 4th December 2019 at 15:38.
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Old 4th December 2019, 15:35   #29024  |  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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Last edited by jdobbs; 7th December 2019 at 15:28.
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Old 4th December 2019, 15:52   #29025  |  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   #29026  |  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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Last edited by jdobbs; 4th December 2019 at 17:26.
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Old 4th December 2019, 17:25   #29027  |  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.

Last edited by jdobbs; 7th December 2019 at 15:29.
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Old 4th December 2019, 19:20   #29028  |  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   #29029  |  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   #29030  |  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?

Last edited by Glarioo; 5th December 2019 at 22:32.
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Old 6th December 2019, 01:12   #29031  |  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 6th December 2019, 01:39   #29032  |  Link
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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 6th December 2019, 11:55   #29033  |  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 6th December 2019, 20:07   #29034  |  Link
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Just reencode an 1920x808 file an the result was 1920x1080. Thanks jdobbs.
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Old 7th December 2019, 04:49   #29035  |  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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Old 7th December 2019, 19:03   #29036  |  Link
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LOL, who cares as long as people are happy with placebos
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Originally Posted by jdobbs View Post
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.
The body can do its own healing very, very well without intervention. I saw much of this so far. But there are times when intervention is required. I can also still see some differences in upscaling from DVD to 720P, but it's becoming more challenging when it's happening with hardware.

I still adore 1080P, but I don't really embrace the 4K thing as so many. Yes, video looks larger, from my phone, yes, outside video of events and nature are really sweet that way. But movies and T.V. shows where there are a lot of makeup and and all that...acne, and stuff...I don't see any reason for that to be really huge. Now, you present Mars photos that large, and other pictures of our planets...I'm alllllllll in! I want to see all that very clearly. I guess it's a "catch 22" to me. Hmm..
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Old 8th December 2019, 05:48   #29037  |  Link
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@Alleycat: Are the original BD discs dual layer 50GB? If so, are you trying to get each one to fit on a 25GB disc?
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Old 8th December 2019, 22:08   #29038  |  Link
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Yes, the 3 original discs are BD50. I was simply creating a backup of each onto 3 separate 25GB discs. The SD video files inside the m2ts containers are mpeg-2.
When starting the x264 encoder, the first line shows "lav [info]: 720x480i 32:27 @ 30000/1001 fps (cfr)". If you import the same file into Handbrake, the dimensions tab shows: "Source 720x480, PAR 32/27".
Those references to 32:27 made me suspect the black bars on the BDRB copy were caused by the SAR 40:33 in BDRB's x264 command line. I found that if I used SAR 32:27, or if I just omitted the SAR parameter completely, both scenarios produced video identical to the source, with no black bars.
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Old 9th December 2019, 03:09   #29039  |  Link
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The SAR of 40:33 is based upon a 704x480 video. With NTSC analog conversion to digital, 8 pixels are removed from each side of the 720 video to get you the 704 video. But, if the 16 total pixels are not removed, you end up with the situation you found yourself in. You could have added an AVISynth plugin command to crop 8 pixels off each side and you should have come up with the correct result [crop(8,0,-8,0)].

The reason for doing the cropping is that in correctly digitized video, there are about 8 pixels of vertical black on each side of the video. By removing it, you get video out to each side, without any annoying vertical black bars.
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Old 11th December 2019, 03:27   #29040  |  Link
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Thanks for your suggestion re cropping. I gave it a try and found that it did indeed remove the bars. The bars had been at the top and bottom, not the sides, but cropping 8 pixels from each side made them disappear. Compared with the original, the height of the picture was now the same, with no part of the original frame missing. The width of the picture was very slightly stretched, with a very small part of each side cropped. Viewed in isolation, I probably would not have noticed, so that's preferable to the black bars.

What I can't figure out is this: If I get BD-RB to convert it from SD to 1080, there are no bars, and nothing is cropped from the edges.

Also, given that the source disc has the SAR of 32:27, does that mean the original BD is not compliant? Or it is allowed for MPEG-2 on BD but not AVC?
That may explain why they stuck with MPEG-2 coding on the original.
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