3D MVC Option

[SiliconKid]

I just read fetef's post again and I think I misunderstood him the first time around.

What he's actually saying is:

1. New Samsung TVs can play MVC 3D properly if it's in an M2TS container using onboard decoding.

2. You can send an MVC 3D movie in an M2TS container to the TV via Plex without affecting the video streams if you use the "Direct" mode in Plex thereby avoiding any Transcoding completely.

3. He tried both the MVC versions (in an M2TS container) and the SBS versions (in MKV containers) of the SAME movies to compare results and found that the MVC versions were far better quality, which makes logical sense because they will be encoded at Full HD for both eyes, every frame. I misread this the first time round, sorry fetef.

[sinious]

Am I wrong in thinking a passive TV is forced to use half resolution (TAB/SBS/Interleave) and active is the only true way to have full HD for both eyes? I just want to make sure the full hd 3d format in discussion here doesn't concern me.

And I'd still love to know how that YouTube video triggers 3D on a TV that I linked. Perhaps LG wired in something proprietary *shrug*.

[docchris]

1) unless you have a 4k TV.... yes, passive TV is only half the vertical res

2) is it the youtube app built in the tv? in which case its just picking it up from youtube

[SiliconKid]

Am I wrong in thinking a passive TV is forced to use half resolution (TAB/SBS/Interleave) and active is the only true way to have full HD for both eyes? I just want to make sure the full hd 3d format in discussion here doesn't concern me.

And I'd still love to know how that YouTube video triggers 3D on a TV that I linked. Perhaps LG wired in something proprietary *shrug*.

1. The half resolution issue you are referring to is the whole issue of how much resolution each eye actually sees at any given point in time.

That's a completely separate issue from how much resolution is actually delivered to the TV in the first place.

Even with a Passive 3D TV the issue around MVC vs SBS / TAB is still very relevant because MVC delivers full resolution for each eye to the TV, whereas SBS or TAB only deliver HALF resolution for
each eye to the TV.

Which means that despite the fact that what your eye sees via passive glasses at any one point in time is effectively half resolution, the image that your are looking at is not half resolution to begin
with if the source is MVC, which means it's a better quality image to start with and will therefore still look better than SBS or TAB.

With SBS or TAB you are delivering a horizontally or vertically compressed image for each eye to the TV which has to then decompress those images and "stretch" the images to full resolution, and
in doing so it has to manufacture pixels that were never there to begin with.

With MVC, you get native full resolution and what is displayed is exactly what the TV received, nothing was manufactured.


2. The TV that automatically kicked into 3D for a YouTube video is probably one of those TVs that scans the image and automatically works out that it's an SBS or TAB 3D image.

[SiliconKid]

"And I'd still love to know how that YouTube video triggers 3D on a TV that I linked. Perhaps LG wired in something proprietary *shrug*."

I did some more research on this quickly because it interests me too and it seems like certain TVs, that have decent native decoding capabilities, recognise certain 3D file naming conventions and also look for a specific flag in the MKV file header and that's how they know to switch to 3D automatically.

The MKV header flags are:

'frame-packing 3' for SBS and 'frame-packing 4' for top/bottom.

The switch for MKVMerge is something like: --frame-packing=3

What's important to understand here though is that those TVs can only do that if you play the file on the TV itself using the TVs built in decoder.

You will notice that when people get that to work they are always plugging a flash drive or external hard drive straight into the TV and then the TV automatically figures out what mode to switch to.

In that case, streaming the media to the TV via something like Plex or XBMC is NOT going to work because the TV has no access to the file name, it only sees the video stream coming in over HDMI.

So there are basically a few different ways that 3D mode switching can occur with TVs:

1. The TV is able to scan the images it's displaying and detect that a frame actually contains 2 of the same image compressed horizontally or vertically (SBS or TAB) and will
then switch into the correct 3D mode accordingly. Generally only more expensive TV models can do this as far as I can tell.

2. You play a 3D BluRay in which case pretty much every 3D TV will automatically switch to 3D because a special flag is transmitted to the TV in the EDID packet sent to the TV
over HDMI from the BluRay player.

3. Some kind of software connects to the TV via a network connection and remotely switches the TV into a specific 3D mode (3D enabler plugin for XBMC and Samsung TVs can do this).

This will obviously only work for TVs with network adapters that allow themselves to be remote controlled over a network connection.

4. If you play a file on the TV itself using the TVs only built in media file decoder and player it's possible for certain 3D TVs to detect what 3D mode it should switch to based on
the name of the file itself and certain file naming conventions.

Things like this may work:

TestFile.3d.sbs.mkv
TestFile.hsbs.mkv
TestFile.htab.mkv

And many other variations which may differ depending on the TV brand.

OR

The "frame-packing" flag in the MKV header

'frame-packing 3' for SBS and 'frame-packing 4' for top/bottom.

The switch for MKVMerge is something like: --frame-packing=3

[sinious]

SiliconKid ~

That's a completely separate issue from how much resolution is actually delivered to the TV

That's a bit confusing for me being I'm assuming at 1920x1080(p) @ 24fps I'm getting exactly 24 frames, half of each is dedicated to a specific eye. How is it possible, on a non-4k TV, to get a full frame for each eye in passive using MVC? For that to even make sense to me, you'd need to double the frame rate and literally shoot 48FPS, showing a full left, then full right, or interleaving at the same speed.

I think what you're getting at is SBS/TAB already has the resolution reduced so it requires stretching/inventing pixels to fill the frame. In contrast, MVC is being reduced from full resolution to half before being displayed. I can assume that might be easier on a decoder and/or the pixels chosen to display would be more choice than an upscale algorithm may produce. Ultimately, both ways, you have the same number of pixels being shown.

I didn't give it much thought but I grabbed a 240hz display. I was hoping this was going to compensate in some way by allowing me to run faster content to make up for the quality.

Thanks for the tip on the MKV headers. I'm a programmer so I know exactly what you mean by it matters if the TV is handed the data in a stream (HDML/software decoded/etc) or if it's a file the TV actually has access to (filename, raw header and metadata, etc). What doesn't make sense is why some player like XBMC or ANY player would receive an EDID handshake and not pass it on. That's what's blowing my mind. How hard is that to really do?

[rant]
*load video in player* -> *figures out 3d* -> *ignores sending any semblance of that data to the TV willingly*.. That's very poor programming. 3D is still squarely in the niche category, but it's really disappointing all these players would ignore something widely available from phones, tablets, laptops, handheld gaming, TVs and projectors.
[/rant]

I'll try the --frame-packing=4 method, thanks for that great tip!

[SiliconKid]

I think what you're getting at is SBS/TAB already has the resolution reduced so it requires stretching/inventing pixels to fill the frame. In contrast, MVC is being reduced from full resolution to half before being displayed. I can assume that might be easier on a decoder and/or the pixels chosen to display would be more choice than an upscale algorithm may produce. Ultimately, both ways, you have the same number of pixels being shown.

1. Correct, that's exactly what I was getting at. The upscaling will never give you a picture of the same quality as the original source material, so even if Passive only effectively gives you half res per
eye on viewing, the MVC source material still gives a better result comparatively, which is why the BluRay 3D version of a movie played from an actual BluRay player WILL look better than an SBS
encode of the same movie played via XBMC or Plex for example, on the same Passive 3D TV.

[rant]
*load video in player* -> *figures out 3d* -> *ignores sending any semblance of that data to the TV willingly*.. That's very poor programming. 3D is still squarely in the niche category, but it's really disappointing all these players would ignore something widely available from phones, tablets, laptops, handheld gaming, TVs and projectors.
[/rant]

2. From what I've read there are 2 issues with the whole EDID thing:

a. Yes, it is very difficult to modify the EDID packet apparently.

b. Even if you do manage to figure out how to modify the EDID package on-the-fly, I don't think that the HDMI standard itself supports separate flags for SBS and TAB, which means you still can't
actually signal to the TV to switch into the correct 3D mode because all you will end up doing is setting the 3D flag used by Blu-Ray players, which actually players that Frame Sequential 3D is on
the way. Which would help for MVC 3D, but not for SBS or TAB.

[sinious]

SiliconKid ~

Interesting, so the spec is so unformalized I can expect that 3D bluray discs won't even trigger the correct passive mode, they'll just have enough information to trip the TVs 3D function and I'll see the same menu come up with SBS/TAB/Interleave/patchy weird things/etc and I need to choose the mode every time. Ugh!

[yadarant]
I feel like 3D is running on the same development path of things like web standards. It's taken over 20 years to get a <video> tag. I can only imagine how many revisions of 3D there will be, further giving players and TVs a good reason to never mature the spec.

Now we have 4K TVs and who knows what kind of tricks they're going to pull so that's going to confuse the spec even more.
[/yadarant]

At least my TVs remote acts as a wireless mouse on the screen so it's only as painful as 3D Button->Hover on SBS->Select... And it sounds like I better get used to it.

Thanks for all the great info!

[docchris]

Interesting, so the spec is so unformalized I can expect that 3D bluray discs won't even trigger the correct passive mode, they'll just have enough information to trip the TVs 3D function and I'll see the same menu come up with SBS/TAB/Interleave/patchy weird things/etc and I need to choose the mode every time. Ugh!

I dont understand what you mean???

You put a bluray in your bluray player... it tells the TV this is a 3d signal... and then the tv changes into whatever 3D mode it is capable of displaying (be that passive or active)

There is no confusion there???

[docchris]

dont forget that the TV is being fed a 3D signal in that case....

this is NOT the same as TAB/SBS or any of that other crap which is a 2D signal...

the TV knows exactly what to do with a 3D HDMI Signal

[SiliconKid]

@sinious:

3D BluRay discs will trigger the correct frame sequential mode on the TV and you shouldn't have to manually intervene at all.

It's the other modes that are the problem. As far as I know the EDID signalling will ONLY trigger the frame sequential mode, there is no support for the other half modes.

The HDMI standard only cares about the BluRay 3D standard, it doesn't care about all the other weird and wonderful 3D encoding schemes that don't deliver Full HD to each eye.

[sinious]

docchris ~

I'm not saying the bluray player won't trigger 3D (my cable box does that just fine, I know it can be done). I just needed SiliconKid's extra information to finally wrap my head around it.

SiliconKid~

Ok so the source is sending full 3D at the TV. It then becomes the TVs job to convert that full 3D signal into what it supports itself. As in, my TV is taking full 3D frames and is squishing them down however I tell it to. Due to having both full frames for each eye, at that point I should be able to choose any 3D mode I want for display, correct?

What got me terribly confused was my cable box (Verizon FIOS (Quantom)) forces SBS. I have no settings in my cable box to adjust. I choose any 3D content on demand and my TV fires up SBS. Thing is, if I change it to any other mode, the 3D looks all out of wack.

Here's what I don't understand about FIOS. Why can't I set my TV to any other setting than SBS and still have it work? If what I mentioned above, "a TV can interpolate a full 3D source into TAB/SBS/etc, then I should be able to choose my preferred mode. Maybe I'm thinking too much like a programmer (overanalyzing) but my first assumption is FIOS is reducing bandwidth by forcing 2D SBS so they never need to send more than a standard HD signal.

That also makes me wonder, do 'active' TVs support SBS/TAB/etc? If not then that would mean FIOS either wouldn't work with those sets, or FIOS can send full HD, but is detecting that my set is passive (somehow) and is optimizing the stream for it.

Now I have more questions than answers hehe

[docchris]

As in, my TV is taking full 3D frames and is squishing them down however I tell it to. Due to having both full frames for each eye, at that point I should be able to choose any 3D mode I want for display, correct?

NO!

your tv is being sent Full 3D frames, yes

but what choice do you think you have?

your tv only has one 3D display mode - whether thats active shutter, or passive/interleaved, or polarised (for some projectors) even!

it converts the incoming full 3d frames from the HDMI cable.. into whatever pattern of light your tv happens to output

SBS/TAB doenst apply here.. those are ways of converting a 2d picture (comprised of two frames) into you TV's 3d output

[docchris]

"a TV can interpolate a full 3D source into TAB/SBS/etc"

that bit is what is a total misunderstanding!!

TAB / SBS is the SOURCE..

your tv cannot take in full 3d frame packing.. and then display a 2d SBS from it! thats ridiculous, what would be the point???

and yes, my active tv supports SBS and TAB as INPUTS...

it takes the 2D HDMI signal, comprised of a TAB / SBS 2d picture.. and then displays that in its active 3D picture

[SiliconKid]

@sinious:

You are confusing the source with the actual display of the 3D movie, the 2 things are related but not the same thing.

1. The terms we are throwing around, like SBS, TAB and Frame Sequential are the ENCODING methods used to package the 3D, they are not a display method.

2. A 3D TV only really has one way to display a 3D movie. It first needs to do some decoding on whatever 3D encoded material you throw at it to get to a point where it has a stream of full frames for
both eyes that it can then display appropriately.

3. You cannot randomly switch between different 3D modes on your TV for the SAME source material. 3D source will be encoded 1 specific way and you WILL need to put your TV into the right 3D
decoding mode to see proper 3D.

4. Cable providers decide on a specific 3D encoding format and then broadcast all of their 3D content in that 1 format.

You were correct in assuming that they will typically choose Half-SBS or Half-TAB because:

a. Those formats require the same number of transmission frames and therefore exactly the same bandwidth to transmit as the 2D equivalent of the same movie.

b. Because those formats package both the left and right eye frame into a single normal frame, there is nothing special required to transmit those frames.

No special equipment is needed and nothing in the broadcast chain changes at all.


5. The source you send to the TV can be 1 of 2 things:

a. Full HD both eyes - BluRay disc or MVC MKV or M2TS file.

MVC MKV or M2TS can give you the exact same quality as a BluRay disc but is not currently well supported by players.

b. Half-SBS / Half-TAB type formats where frames are compressed and effectively half the resolution of the original source material (BluRay disc that was ripped) is now being delivered to the TV for each eye.

The "Half" is important because you also get Full-SBS and Full-TAB formats where there is no compression of frames and the frames transmitted are massive double sized frames,
but in practice that's very uncommon and most equipment out there doesn't know how to handle that.

Half-SBS is the most popular format in download circles, followed by Half-TAB.

6. Active 3D TVs support exactly the same things that Passive 3D TVs support, the encoding formats have nothing to do with it.

The difference between Active and Passive 3D is:

a. The technology employed to deliver the picture to your eyes.

b. Active will always deliver a full resolution frame to each eye whereas Passive technically only delivers half a frame to each eye at a time, but there are massive debates about
whether your eye even notices the loss of resolution with Passive.

I have an Active 3D Samsung TV and personally I think it's better than Passive, but that's just me.

7. "a TV can interpolate a full 3D source into TAB/SBS/etc"

I actually don't really know what that means, but as far as I'm concerned that's wrong. A 3D TV needs to be told what kind of 3D source material it is being handed so that it knows how to
decode that source properly.

You would never send 3D BluRay source which is Frame Sequential to a TV and then put the TV in SBS decoding mode because that makes absolutely no sense.

So in summary:

3D Source Material (video file or BluRay disc) is encoded in a certain way ---->
3D source is sent to TV. Can be over HDMI cable from media player or cable box or from local Flash drive or Hard drive plugged into USB port on TV ---->
TV needs to know what it's receiving so it can decode properly (EDID packet tells it for BluRay, you tell it with remote control for SBS / TAB etc.) --->
TV decodes source and extracts full resolution frames for both eyes. For BluRay and MVC they arrive that way, for Half-SBS/TAB some decompression is required --->
TV displays decoded 3D movie using ONE standard display method.