How to reverse 3D full frame?

[tommy2010]

Hi there,

Once in a while I run into this problem that when I do a backup of my 3D blu-ray in order to play it back on my Dune HD Base 3D, the eyes are reversed with me having to reverse them back either on Dune itself or the projector. The latest such film is the Edge of Tomorrow 3D. I did some googling and from what I understand the eyes can be reversed by opening the movie's playlist in a Hex editor and editing an entry but unfortunately I was not able to find more information about it. Have any of you tried it and if so can you walk me through on how to do it with the XVI32 Editor?

Just so it's clear I'm talking about reversing 3D MVC full frame and not 3D Side by Side.

Thanks

[Cornucopia]

MVC is encoded with 2 parts: the BASE stream (=2D AVC format) and the DEPENDENT stream. The BASE stream could be either the L or the R viewpoint (usually it is the L, but I guess it is possible for that to be not universal). The DEPENDENT stream consists of the visual differences between the L and R views. This is much like the motion differences of P or B frames compared to I frames (in fact, they're VERY, VERY similar, but the DEP view has NO I-frames).

I have not ever had the need to inspect the MVC stream to see where the metadata is that governs which viewpoint is the BASE one, so I can't really help you there. However, it might be similar to the HDMI SEI signalling data. That kind of thing is going to be hard to find, though, because I would expect it NOT to be coded in a human-readable form (such as L or R), but rather in a binary form (0, or 1). The only way to know for sure is to check either the official MVC specs or the documenation for a reference encoder (such as Nokia's). Or check with the developer of FRIM.

Scott

[ndjamena]

The flag is in the playlist I think, not the actual stream. If you've ripped it into an MKV and there's no option to reverse the viewpoints in your player then you're out of luck.

[Cornucopia]

I don't know why it would be in the playlist, as it is integral to the correct decoding of the image(s). Why do you think that it would be otherwise?

Scott

[ndjamena]

I read it on the MakeMKV forum, and they linked to a post on Doom9.

Mike seemed to believe it. I don't have a 3D TV, or a 3D Blu Ray player and the only 3D Blu Ray I have is "The Day of the Doctor". I haven't any actual experience with this. I can only repeat what I've heard.

[tommy2010]

@Scott Thank you for the reply even though it's a little too much for me to comprehend at this time. However, from what I gathered so far it appears as the 2D stream is being manipulated via the MVC stream for the 3D. I haven't tried transcoding the 2D stream yet but have added custom subtitles and audio streams, etc. without affecting 3D. My prediction is that even if I were to compress the 2D stream then as long as I mux it back up with the original film's MVC I'm still going get the movie in 3D though wonder if more cross talk will be visible as a result.

Anyways it does sound curious but the information I gathered thus far is that the eyes can be reversed within the playlist and if that's so then I very much would like to know how.

@ndjamena The only way I can play 3D full frame on Dune and it looks to be true for other devices as well is if it's a Bluray structure within an ISO. So I do have the original playlist for the film just don't know what to do in it to reverse the eyes if that's even possible. I attached the screen shot of the Edge of Tomorrow 3D playlist within the hex editor if anyone has any ideas. The information I found in another forum is as follows:

Hello, use for example (XVI32) hex editor, open * .mpls main, inside BDMV / PLAYLIST, replace @ ASCII hex value (40) to hex ​​(50) ASCII p. This reverses the eyes.

Based on the screenshot from the Edge of Tomorrow playlist, the quote makes no sense.

[ndjamena]

Here we go:

http://www.makemkv.com/forum2/viewtopic.php?f=1&t=7863&p=34013&hilit=left+right#p34013

That's all I know.

[tommy2010]

Hello again,

I came across something in another forum that I wanted to share with others looking for a solution to this issue, didn't have time to test it yet but strongly believe it will solve the problem. Anyways, the new tsmuxer has a setting under the Blu-ray tab for 3D "use base video stream for right eye". I believe this will create a flag in the final output to reverse the eyes for those 3D discs with the right eye as their base. I'll report back with findings when I try it out.

Thanks for your replies.

[Cornucopia]

Think about this:

If my BASE view is supposed to be L, and it shows a circle in the center of the screen, and my DEPENDENT view says the motion/parallax vector is shifted over x pixels to the Left (or "-x" pixels) for the entirety of that circle, you would be getting that circle poking out of the window of the screen plane into viewer space.

If, however, the BASE view remains the same (still assumed to be L view), but the DEPENDENT view puts the motion/parallax vector at "x" pixels (notice the change in sign), that means the vector is shifted over to the Right for the entirety of that circle, which would give you the impression of that circle poking into the background/screen space. In other words, the change of the M/PV sign is the equivalent of the swap in the parallax, aka the swap in the eye view.

So, it looks like there could be up to 3 different places where this could be designated and/or determined: 1. In the userdata? of the AVC-encoded BASE view, 2. In the sign(s) of the M/PVs of the DEPENDENT view, or 3. In the metadata in the MPLS.

hmmm....

Scott

[ndjamena]

Since I doubt the MVC flag was part of the original Blu Ray spec, it makes no sense that you'd simply be able to open any random Blu Ray playlist and find a flag you can change to set it. If you didn't specifically add a field to add that flag to, I doubt it's there. Whatever example you found was most likely just someone's attempt to PROVE that there is a flag in the playlist that determines which eye is the base.

http://en.wikipedia.org/wiki/Multiview_Video_Coding

I think MVC may have more uses than simply showing 3D movies, it's essentially two video tracks in one. The playlist and the Blu Ray specs is probably the best place to designate what exactly should be done with each of the pictures the decoding process creates.

[ndjamena]

Cool, I just noticed MMG has a "Steroscopy" field in "format specific options", it looks as though whatever the thread on the MakeMKV forum was about was dealt with.

http://matroska.org/technical/specs/notes.html#3D



I'll have to save up for a 3D TV one day.

[jman98]

Mike seemed to believe it.

Oh well, that makes ALL the difference in the world if Mike believes it.

But seriously, would it have killed you to provide some context as to who exactly Mike is and why anybody would care what he thinks?

[ndjamena]

Mike seemed to believe it.

Oh well, that makes ALL the difference in the world if Mike believes it.

But seriously, would it have killed you to provide some context as to who exactly Mike is and why anybody would care what he thinks?

Sorry, Mike is the developer of MakeMKV and I assume he knows more about the Matroska Container than me.

One of the developers of Handbrake is on the MakeMKV forum, he's LibAV as well. Apparently there's something called #matroska on IRC that I'm not part of. Mosu and some other guy invented most of the Matroska system, apparently the tagging system is the other guys baby. Since I didn't recognise the name of the guy who invented the chapter system, I assume there's a third as well. I don't actually know how the people who maintain the Matroska system are organised, (I was going to finish with "but they must be" but...)

-Edit- And I should think he'd know more about meddling with Blu Ray internals than me too.

-Edit2- Sorry, I'm still stuck pondering PDRs suggestion that Mosu was doing all the Matroska stuff

[jman98]

Thank you for the explanation. I appreciate that.

[tommy2010]

Hi guys,

I tried experimenting in order to get the 3D eyes reversed with tsmuxer and unfortunately the process I thought that would work doesn't. The tsmuxer has the 3D option "Use base video stream for right eye" under the bluray tab but when checked it does absolutely nothing. I tried just importing the streams and checking this option as well as opening the playlist and checking this option also to no avail. As I mentioned before someone said of changing the hex value of 40 to 50 in the playlist using a hex editor but the playlist from Edge of Tomorrow 3D as an example does not contain the 40 value. Yet there must be a flag somewhere that tells the film how to play and I would appreciate it if someone has any ideas of what to try in order to change it from right to left.

Just wondering how does 3D in MKV work? Have found some old posts that suggest full frame 3D is not possible in MKV, is that still the case?


Thanks

[Cornucopia]

I won't comment on your use of tsmuxer, not fully knowing what you started with, what settings you chose, nor what you truly ended up with...

I'm gonna assume when you say "how does 3D in MKV work", you mean how can various 3D types be stored and flagged, right?
This link: http://www.matroska.org/technical/specs/notes.html#3D explains the options.
In a nutshell, you have a choice between FrameCompatible formats and ServiceCompatible formats.
Frame-compatible means that the 3D signal has been made to FIT into a standard 2D-compatible Frame, either through arranging SbS, TaB, FrameAlternating, etc or by matrixing the color into Anaglyph. The file doesn't have any special decoding and/or bitrate requirements and can work in regular 2D pipelines, but it is not directly 2D Backwards-compatible.
Service-compatible means the use of enhanced, stereo3D-aware decoding and the use of extended coding: MVC or Dual-stream/track muxing, etc. Service-compatible formats require an enhanced decoder for the 3D to work, otherwise only a 2D version is decoded. But this also makes this format intrinsicly directly 2D Backwards-compatible.

Yes, fullframe 3D is possible in MKV and any (every!) other major container format. Whether fullframe 3D is acceptable or not really depends on the design of the player/editor application and the bandwidth limitations.

Scott

[tommy2010]

Hi Scott,

To clarify with the tsmuxer no matter what I do I always get the eyes flipped and have to use my Dune player to reverse which is a solution but an annoying one considering that only a select few discs are based on the right eye. Yes the Dune player decodes MVC and it's what I prefer as opposed to the SBS, etc.

I started researching more about MKV because correct me if I'm wrong but it seems that you can configure what the 3D output will be and based on what eye as the base. Having said I am wondering about demuxing the film from the disc with two separate streams left/right, outputting a MKV with the left eye as its base ( will it be StereoMode: 13 both eyes laced in one Block (left eye is first) or...? ), and finally muxing the MKV into a Bluray ISO using tsmuxer so that my Dune can play it as a 3D disc. Is that possible? If I were to get the streams separate for both eyes is there a way to get them back as the h264 video stream/MVC and if so how to I go about it? It appears that I can get the two separate streams by demuxing with Eac3to but then what?

Forgive me for being a such a newb but info for 3D is very scarce and outdated for the most part so I'm trying to find as much as I can myself and hoping that someone that knows better will help me fill in the blanks.

Thank you for your patience.

PS: I also found that there is a bug with the tsmuxer and 3d planes for subtitles. When played back the subtitles get cut off and every second line or so don't appear at all. To get around this I placed my subs as srt in the ISO folder which works but have to rely on the player for positioning and color. Have you heard anything in regards to the 3d planes for subtitles and if there is a fix for this problem, perhaps only certain planes are buggy? So far I only used 3d plane 1.

[ndjamena]

Have you tried making a straight rip of you original disc, without modification and playing that back on your dune?

Is it possible your Dune player simply assumes which image is left and which is right and doesn't actually read what the playlist says?

[tommy2010]

@ndjamena I'm using DVDFab for backup and have to look into whether or not I can dump the entire disc to HDD. I never much cared for the menus and special features so I always only dump the main movie. Most discs use the left eye as their base and so Dune plays it as intended but a select few usually from 20th century Fox are based on the right eye that I have to flip. This is not just Dune, I read about others with different devices that experience the same thing and with the same discs. So as someone mentioned this most likely has to do with how the disc was authored.

[ndjamena]

I know MakeMKV WILL do a straight rip in "backup" mode, I can't imagine why DVDFab wouldn't be able to do the same.

Stereoscopic player was playing MVC 3D videos long before anyone realised there was something in the playlist that determined left and right. It's highly unlikely they were the only ones fooled.

[Cornucopia]

One can always do a rip -> demux -> decode to 2 views -> re-encode to MVC -> mux to MKV (or 3DBD). But this is a waste of time as well as (probably) a big loss in quality.

I honestly think it has something to do with your process...

Scott

[Cornucopia]

This seems like it might have some clues to a possible solution: see NAL & VID info https://tools.ietf.org/html/draft-ietf-payload-rtp-mvc-02
(yes, it's to do with RTP, but the elements involved should still be valid)

Scott

[tommy2010]

Hi Scott,

I'll examine the info you provided more closely but at a quick glance it appears like info for those that deal with software for MVC encoding which is beyond my comprehension.

If it were a problem with my process then every 3D film I ever backed up would be wrong and not just a select few and not to mention the same few that everybody else has the same problem with.

The process of demuxing and then muxing back up yes it will take time but considering that there is no transcoding involved there shouldn't be any quality loss. Besides I still maintain that it's a flag issue that someone out there must know how to change.

I'm very baffled how there is no information about this considering that this is not an isolated nor hardware specific issue and believe that to those who fully understand the 3D MVC format this probably is a very simple fix.

[ndjamena]

Until you make an unaltered, 1:1 rip of your Blu Ray and test it on your Dune player any further discussion is a waste of time. If the people who made the device didn't know the flag existed then they'd just assume the most common form of 3D (ie the only one they'd ever seen) was the standard. There's no point in changing a flag if the player can't read the thing.

To the people who REALLY understand 3D MVC, the simple fix is to watch the damn movie from the original disc on a blu ray player.

[Cornucopia]

Maybe you misunderstood: my post #21 mentioned what you can do to verify & avoid wrong-eye-view but it does so at the expense of quality loss due to re-encoding. Simple demux from M2TS/SIFF -> remux to MKV actually would SAVE time and quality, but doesn't affect a change in the (intended?) viewpoint.

There's not NO info, there's just "secret" info (read $$$ buy-in), but there's plenty of it. I would think an extensive analysis of extant MVC samples off of 3DBDs would lead one in the right direction, I'm just not prepared to attempt that right now.

Remember what I was saying earlier, it might not just be a flag issue. I cited 3 places where information could affect the outcome, and one could even be at odds with another.

Example:
Movie 1 uses Left Eye=Base stream (listed either in the playlist flag somewhere or in the encode somewhere), and has Dependent stream showing negative signed difference (left-shifting) vectors giving negative parallax.
Movie 2 uses Right Eye=Base stream, and has Dependent stream showing positive signed difference (right-shifting) vectors giving negative parallax.

Both movies show (correctly & appropriately) 2 views going to their corresponding eyes and showing image which pops out of the screen!
If a software only expects one variation of this, it will screw up on the other.

Also, I'm not convinced that the Main stream (the 2D AVC portion) does NOT have a flag in the encoding. It is fairly inconsequential to add an additional header which designates the stream eye-view but because it is not standard AVC is IGNORED by standard 2D decoders. Just like one can add on custom user metadata (in a sense that's what this is).

Scott

[tommy2010]

@ndjamena: Since you so strongly insist I will do a dump of the full disc and test it out. But don't see how this will make any difference unless there are instructions for how the disc should play hidden inside the menus.

The designers of Dune must have been aware of the issue hence they built in a real-time function to flip the eyes right into the player which is conveniently switchable with a single button on the remote. Furthermore, even the 3D projectors like by Panasonic have that functionality. So, obviously they anticipated that some media will have their eyes crossed and provided the functionality so that we wouldn't have to wear the glasses upside down.

[Cornucopia]

That was designed in because there are some formats which have NO facility to designate the difference.

Scott

[Cornucopia]

This seems to have some good info: http://www.ist-sea.eu/Public/SEA_D3.2_HHI_FF_20090129.pdf.

Scott

[ndjamena]

@ndjamena: Since you so strongly insist I will do a dump of the full disc and test it out. But don't see how this will make any difference unless there are instructions for how the disc should play hidden inside the menus.

The designers of Dune must have been aware of the issue hence they built in a real-time function to flip the eyes right into the player which is conveniently switchable with a single button on the remote. Furthermore, even the 3D projectors like by Panasonic have that functionality. So, obviously they anticipated that some media will have their eyes crossed and provided the functionality so that we wouldn't have to wear the glasses upside down.

The mpls files contain all the info to play titles, if your dune player is playing a BD rip it should be displaying titles taken from the mpls files for playback. If it's just playing the m2ts files directly then it shouldn't be. When you rip out just a title from a disc whatever program you're using must modify the mpls file somehow, if it's removed the 3d mode then a straight rip should correct it, if it hasn't then it's your dune player that's the problem. Unless it's java that's setting the 3D mode. In any case, I don't see why a setting to switch left and right is proof that Dune properly reads the 3d mode field.

[Cornucopia]

I agree.

Scott