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  1. I have found mixed information regarding this on internet;

    I also posted the question at the program site but I trust everyone here for their input, plus it is also more of a general question I had as you can technically do this with BDRB as well.

    There is a program that will place a UHD to Blu-ray on a standard BD50 disc. I understand a simple compress to get from the size of the UHD disc to a BD50 size but when it comes to the actual bitrate it is much higher for UHD titles and as we all know there is a bitrate 'cap' to non-UHD discs (well I suppose there is one for UHD as well but it is much higher)

    So does this higher bitrate then compromise the playback of the standard BD50 disc on a stand-alone BR player?

    The information I have found is mixed;

    1. Some sources state the additional bitrate cap is from the HVEC encoding and basically you can place that on a standard non-UHD 50gb BDR disc with no issue.

    2. While other information I found says the bitrate from the UHD title will exceed the cap placed on it by the player expecting a standard BDR disc and thus issues when placing that UHD title on a regular BDR (50gb) disc so likely playback issues.

    By standard disc I mean the Single\Dual layer 25\50gb discs and not the specific UHD BD66\BD100 discs.

    So I guess I am asking if there is anything special (other than layer sizing) about those BD-XL 66\100 discs that allow it to use the much higher bitrate of UHD or is simply the encoding method and the older SL\DL discs will be fine with it.
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  2. Member Cornucopia's Avatar
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    #2 is correct.

    Besides having different codec & resolution/gamut/dynrange, UHD BD discs allow for greater max bitrate (72, 123, or 144Mbps depending on disc layer & capacity type) than do 3D BD discs (48Mbps) or standard HD BD discs (40Mbps).

    Even if you change to former qualities to HD BD expectations (1920*1080, SDR709, AVC...), if you do not cap your max bitrate to under those expected by standard BD players, you have a Very good possibility of buffer underruns which exhibit skipping, stalling, freezing, maybe crashing. That's IF your BD authoring app even accepted the encode. Most will not if they aren't compliant - sometimes rencoding it again for you, sometimes just baulking.

    For it to be BD compliant, you also have to meet other encoding criteria like VBV buffer size. Best to just use a BD-compliant encoder, or and encoder that you can apply a BD-compliant encoding profile/template.



    Scott
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  3. Cornucopia, thank you for that.

    Well, that's interesting then - the program (DVDFab) keeps HDR10, resolution 3840x2160 etc. but can place that (albeit compressed of course) on a BD50 disc so at some point it is not only compressing the title but also capping the bitrate as well - to be fair they also offer BD66 & BD100 options as well, so that would be the BD-XL media.

    I had done a test using BDRB and it of course compressed it down as well but according to Mediainfo it has a 49.1 overall bitrate and 35.5 maximum overall bitrate, although I suppose Mediainfo doesn't show the peak bitrate number?

    So it would be interesting to see what the DVDFab version would do as far as it's bitrate.

    If the media wasn't so expensive I'd like to also test a BD-XL burned to just under 66gb (3 layers) to see if it'll play on my player as I also read that players can play a BD-XL disc as long as it is not all 4 layers.
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  4. Member Cornucopia's Avatar
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    What DVDFab is creating is a quasi-UHDBD. Which IS NOT STANDARDS-COMPLIANT. Partly because there is NO standard for home-burned UHD-BDs. But what you get is also NOT a standard BD, but an attempt at a UHD BD. That means, you won't know which player(s) will work with it. I am giving an educated guess when I say almost NO standard BD players would be able to play it, because even though they might support UHD resolutions AS FILES, they still do not support UHD BDs and that is a completely different logic & playback support path. Some, but more likely FEW, UHD BD players may support it. It wouldn't be universal because they are using non-standard media (for UHD standards), and we do not know how compliant DVDFab could have made their re-authoring app, since they would have to completely reverse- or re-engineer it. Considering their history, suffice it to say the Bluray Consortium would NOT grant them licenses for the real specs for authoring (BD or UHD BD).

    Caveat Emptor


    Scott
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  5. It seems you are thinking of DVDFab 'UHD Creator' there, and I am aware of those issues with that as far as authoring and I would agree that unless you are using a 'real' UHD authoring environment ($$$) any player would likely have issues with some sort of hybrid that it would be making.

    I was talking about their standard 'full disc copy' feature, much like BDRB it simply takes a full UHD disc and compresses it down to a BD50 sizing. The difference is that BDRB (other than to compress) will not touch the bitrate. The DVDFab copy 'should' I would think not only compress the size of the title to BD50 size but 'should' also then cap the bitrates some for compatibility.

    Guess I'll find out as I have a BDRB compressed version and I'll run the same full sized UHD through DVDFab Copy and see what the bitrates are for that one.
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  6. For future searchers; The disc I made compressing with BDRB to BD50 did play with no issue on my Samsung U8500 & Oppo 203 - However I only played about the first 15 minutes or so and that was fine, I didn't play through whole movie so if there were 'bitrate issues' later on I didn't find it yet, that is why the original question (I of course tossed the disc once I saw it played though).

    If you are wondering why to go through all of this; I have a Foreign UHD title with no subtitles and was inserting in an English subtitle track.
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    Originally Posted by Cornucopia View Post
    What DVDFab is creating is a quasi-UHDBD. Which IS NOT STANDARDS-COMPLIANT. Partly because there is NO standard for home-burned UHD-BDs. But what you get is also NOT a standard BD, but an attempt at a UHD BD. That means, you won't know which player(s) will work with it. I am giving an educated guess when I say almost NO standard BD players would be able to play it, because even though they might support UHD resolutions AS FILES, they still do not support UHD BDs and that is a completely different logic & playback support path. Some, but more likely FEW, UHD BD players may support it. It wouldn't be universal because they are using non-standard media (for UHD standards), and we do not know how compliant DVDFab could have made their re-authoring app, since they would have to completely reverse- or re-engineer it. Considering their history, suffice it to say the Bluray Consortium would NOT grant them licenses for the real specs for authoring (BD or UHD BD).

    Caveat Emptor


    Scott
    What is your opinion (if any) of DVDLogic BD Wizard, which is supposed to be a UHD authoring solution for home and small studio users? Link to info at developer website: https://www.dvd-logic.com/bd_wizard
    Last edited by usually_quiet; 22nd Apr 2021 at 18:04. Reason: wrong product name
    Ignore list: hello_hello, tried, TechLord, Snoopy329
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  8. Member Cornucopia's Avatar
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    I haven't worked with their more recent stuff, but back in the day knew well of their DVD authoring. That I would put at 4th tier (1st=Scenarist, 2nd=Maestro, DVDCreator, DVDStudioPro, 3rd=Encore, DVDArchitect, a few others). So good but not great.
    Since then, they have grown and fixed many bugs, and acquired other assets esp. BD, so I would expect their rep to have improved. I know from minor exposure that BluDisc Studio is quite good for the price, but it still isn't on par w Scenarist, or Sony's, or a few other high echelon products.

    I am going to say they may have "cheated", because they already have higher-end BD toolsets, and so they already know the full BD spec pretty well. I am betting this tech trickled down to the lower products, even though they have much reduced feature set.
    This could sort of include the UHD BD tools. However, as we both know, without a legit published UHDBD R/RE standard, they are going on assumptions that the future burnable spec will closely match the pressed spec.
    But I give them much higher marks than DVDFab (unless Fab has a trick up their sleeve based on gray market IP sources).

    Still, one should proceed with caution.
    Also, I still consider their stuff to not really be "consumer" but rather prosumer/semipro/small business, as per their literature and price points.

    Scott
    Last edited by Cornucopia; 22nd Apr 2021 at 23:48.
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  9. Just to bring this to a somewhat close for anyone looking for this info;

    Cornucopia was correct way at the top mentioning exceeding the bitrate that the BD-50 disc was capable of.

    The test disc I made played absolutely fine for quite a while but when it hit the 1hr mark it skipped\froze\stuttered - I checked the bitrate of those sections where the issue was and they exceeded about 58Mbps to 66Mbps - the highest up to that point is about 49Mbps to 53Mbps so not bad there but it definately choked at that much higher bitrate.

    Also note that this was a test disc that I made and used super crappy Ridata DL media for as I didn't want to waste a test on my good media so potentially the better media (Verbatim\Panasonic MID-MEI) and at a slower burn speed (I did it at 6x) might get you more leeway? Not sure about it as I'm not going to test that theory.

    So there you go; if anyone plans on taking this route not only will you need to compress for size (somewhat depending on title of course) but you'll also need to account for bitrate spikes and cap that as well, Premiere (latest versions) is able to do that while keeping HDR intact - but no way around encoding the original some unfortunately.
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  10. I suggest doing .mp4 file on disc/usb until powerdirector or tmpgenc come out with 4k BD solutions. All the work arounds I've seen have issues on various players and various BD-r brands. Or drop major cash on the pro software then output to .iso and burn to disc.
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