Req [3D] DLP Projector and RPi2 - frame-sequential
#1
I just want create separated topic to find users who wants this rpi2 features and see how much users want this features (and possibilities to donate developers).
I hope that I didn't break the rules of forum. Thanks.

I already asked.Here is our story.

@ivota - my request, first question.
3D Ready DLP Projector can only receive 120Hz frame sequential format video to achieve 3D effect, so 2D and
3D format (SBS-H/TAB/FP) video can't be view in 3D ready DLP projector at 3D mode.

@popcornmix - developer answer
It may be possible from a hardware point of view, but as I don't have a display that supports frame-sequential 3D it's hard to add support for it.
Also as most 3D TV's support do support half-SBS, half-TAB or frame-packed 3D output, supporting another less common format will be low priority.
It is on my list of things I'd like to look into, but no promises of when it will happen.
Reply
#2
I've looked through the HDMI 1.4 spec and there is no reference to "frame sequential".
It does describe Frame packing, Field alternative, Line alternative, Side by side (full), L+depth, L+depth +Gfx + Gfx-depth, Top and bottom, Side by side (half), Top and bottom (half).

So I need to know if "frame sequential" is something outside of the hdmi spec, or just another name for one of the official 3D formats.

A link to the projector manual that describes "frame sequential", or any other information that describes the standard would be useful.
Reply
#3
Frame sequential = Page flipping (page-flip)

Image

Frame sequential, also occasionally called page-flip, is in some ways the simplest of the 3D formats. A frame sequential signal is a full resolution picture sent at 120 frames per second to the display. The frames alternate in sequence, so the display receives a left eye frame, then a right eye frame, then a left eye frame, and so on. This is simple because the projector itself does not need to do any decoding of the source; it just needs to be capable of accepting a 120Hz signal. Correspondingly, this format requires a lot of bandwidth, since it is essentially sending a full resolution signal at 60 frames per second for each eye. This is double the bandwidth of a comparable 2D signal.

In the world of projectors, frame sequential is an important format. Today's inexpensive DLP projectors that are touted as "3D Ready" accept only frame sequential 3D. And at this writing, their 3D capability is limited to a maximum of 1280x720 resolution.

Full text look here: http://www.projectorcentral.com/what_doe...y_mean.htm


Quote:A link to the projector manual that describes "frame sequential", or any other information that describes the standard would be useful.

On HDMI 1.3 you wont be able to do 120hz@1080p but 120hz@720p should work.
http://www.eurosell.it/repository/imgart...925001.pdf
Reply
#4
(2015-06-01, 15:17)ivota Wrote: Frame sequential, also occasionally called page-flip, is in some ways the simplest of the 3D formats. A frame sequential signal is a full resolution picture sent at 120 frames per second to the display. The frames alternate in sequence, so the display receives a left eye frame, then a right eye frame, then a left eye frame, and so on. This is simple because the projector itself does not need to do any decoding of the source; it just needs to be capable of accepting a 120Hz signal. Correspondingly, this format requires a lot of bandwidth, since it is essentially sending a full resolution signal at 60 frames per second for each eye. This is double the bandwidth of a comparable 2D signal.

Any idea how projector determines which frame is left and which is right?

I can't believe it just counts frames from start of day, as it typically takes many frames for a sink to lock on to a hdmi signal when the clock changes (hence the couple of seconds time taken when switching) and it would mean hotplugging or even switching inputs wouldn't be possible without potentially flipping left/right eyes.
Reply
#5
Quote:Any idea how projector determines which frame is left and which is right?
maybe, manualy by pressing Button on glasses

Image

3D glasses for DLP-Link Ready projector has a button (for power on/off, same button also used for sync picture--->possible switching L and R ).
If picture on screen no 3D, I once press button on glasses and picture become 3d.

Quote:The Digital Light Processing (DLP) 3D ready projectors use the built-in DLP LINK technology to synchronise the active shutter glasses with the display. You just need to switch on the glasses and stay within approximately 5 metres from the screen, and DLP LINK will automatically make the synchronisation, without any need for configuration or extra devices.
Reply
#6
When you drive the projector from windows with working page flipping, can you try switching AV input (if projector supports more than one input) or just unplugging and replugging HDMI lead.
Is the left/right eye order always consistent or does it sometimes flip?
(That is important to know as if it's always correct it suggests there some other left/right signalling going on that I need to know about).

Can you run Pi in 720p120 mode with Kodi connected to projector now?
Do you get an image on display? Play a 2D movie.
Do the glasses lock on to signal and behave as though you were watching a 3D movie (i.e. LCD shutters flickering and movie visible at usual brightness of a 3D movie)?
Obviously you won't get a 3D effect, but I want to know if the projector is treating this as a 3D signal. (Again if it doesn't then it suggests some signalling is required).
Reply
#7
Quote:When you drive the projector from windows with working page flipping, can you try switching AV input (if projector supports more than one input) or just unplugging and replugging HDMI lead.
Is the left/right eye order always consistent or does it sometimes flip?
(That is important to know as if it's always correct it suggests there some other left/right signalling going on that I need to know about).

I do that, play 3d movie then switch AV inpunts (VGA, VGA1, S-video, then back to HDMI)...3D continue works, no problem.

Quote:Can you run Pi in 720p120 mode with Kodi connected to projector now?
Do you get an image on display? Play a 2D movie
.

Yes I can run Pi in 720p120 mode with Kodi connected to projector.
But, first I configure config.txt and add this line. (according this http://raspberrypi.stackexchange.com/tag...g.txt/info)

###720p 120 Hz
hdmi_group=1
hdmi_mode=47

Image

Now I am going to test this.
Quote:Play a 2D movie.
Do the glasses lock on to signal and behave as though you were watching a 3D movie (i.e. LCD shutters flickering and movie visible at usual brightness of a 3D movie)?
Obviously you won't get a 3D effect, but I want to know if the projector is treating this as a 3D signal. (Again if it doesn't then it suggests some signalling is required).
Reply
#8
Quote:Can you run Pi in 720p120 mode with Kodi connected to projector now?
Do you get an image on display? Play a 2D movie.
Do the glasses lock on to signal and behave as though you were watching a 3D movie (i.e. LCD shutters flickering and movie visible at usual brightness of a 3D movie)?
Obviously you won't get a 3D effect, but I want to know if the projector is treating this as a 3D signal. (Again if it doesn't then it suggests some signalling is required)
.

Here is screenshots. Source from USB stick : The.Hobbit.The.Battle.of.the.Five.Armies.3D.H-SBS.2014.720p.
Quote:LCD shutters flickering and movie visible at usual brightness of a 3D movie
I didn't see differences.

Image

Image

Image

Image

Image

Image

Image

Image

Image

Image

Image

Image
Reply
#9
Image

Image

Image

Image

Image

Image
Reply
#10
(2015-06-01, 18:26)ivota Wrote: Here is screenshots. Source from USB stick : The.Hobbit.The.Battle.of.the.Five.Armies.3D.H-SBS.2014.720p.

I'm more interested in playing a 2D movie in a 720p120 mode.
Use the projector and wear the glasses. Do the glasses behave exactly as they do when correctly watching a 3D video?
(i.e. with the shutters flickering)?
Reply
#11
Quote:I'm more interested in playing a 2D movie in a 720p120 mode.
Use the projector and wear the glasses. Do the glasses behave exactly as they do when correctly watching a 3D video?
(i.e. with the shutters flickering)?

I didn't see 3d effect. Video looks as 2D video.
But, I see that picture changes dark- bright-dark-bright... when I wear the glasses, every 10 sec (but not always, I didn't count seconds, some times seems 15 or 5 sec.
Reply
#12
(2015-06-01, 18:40)ivota Wrote: I didn't see 3d effect. But, I see that picture changes dark- bright-dark-bright... when I wear the glasses, every 10 sec (but not always, I didn't count seconds, some times seems 15 or 5 sec.

But if you watch the same 2D movie with the 3D player on windows (Daum Potplayer?) do the glasses behave the same way?

I need to know if the 720p120 signal we output is correct and all that needs doing is alternating left/right image every 8.33ms,
or whether there is some signalling needed to indicate we are in a 3D mode and whether we are outputting left or right image.

Picture going dark/bright every 10 seconds doesn't sound good to me.
With your current setup, it should be behaving exactly like playing a 3D movie that happens to have no depth (i.e. left image == right image).
If that case is not behaving as expected there is no point adding frame sequential support (which is just alternating left/right images) as it will behave the same way.
Reply
#13
Quote:Picture going dark/bright every 10 seconds doesn't sound good to me.

I think that glasses trying to do something.

Quote:But if you watch the same 2D movie with the 3D player on windows (Daum Potplayer?) do the glasses behave the same way?

Can you confirm, Play 2d movie on kodi pi2, enable 3d in kodi player, put glasses, look symptoms?
Reply
#14
(2015-06-01, 19:45)ivota Wrote: Can you confirm, Play 2d movie on kodi pi2, enable 3d in kodi player, put glasses, look symptoms?

No. Don't enable 3D at all.
I want to know what happens when you play a 2D movie in 2D mode from Kodi on the Pi at 720p120 and display with projector and wear the 3D glasses.
I would hope that the shutters will flicker evenly and you will see the odd frames through one eye and the even frames through the other eye.
As it's just a 2D movie the left and right views will be almost identical so it should look just like watching the 2D movie.

The key part of this test is that you should see a watchable movie through each eye of glasses.
If you are seeing it dim every ten seconds, then something wrong is happening.

I would hope what you see through the glasses will be exactly the same as when watching from windows PC using the 3D player with a 2D movie (in 720p120 mode).
Reply
#15
Openelec, kodi player, 2d movie, 3d disable = No flickering. look just like watching the 2D movie. I see clear screen, always.
Reply

Logout Mark Read Team Forum Stats Members Help
[3D] DLP Projector and RPi2 - frame-sequential1