[ILUG-BOM] [OT] Some Technology Observations.

[Rony]

Hello All,

The Homi Bhabha Auditorium at TIFR is just like a cinema hall and it has 
a projector at the back just like a cinema projector but the difference 
is that it is a digital projector and for the first time I saw such a 
big cinema grade and screen size digital projector. Just as some TVs had 
come out with 3D vision where 2 images with different polarizations were 
interlaced and broadcast and then viewed through polarized specs, TIFR 
could also experiment with this technique and give 3D projection a try. 
Another use for the digital projector would be the future cinema 
concepts that the film industry is trying out. They plan to set up 
digital cinemas where the film is simultaneously released through 
broadband or satellite broadcasts in order to avoid piracy. It is also 
usefull for Movie On Demand systems where movies can be randomly 
selected for the particular session without waiting for the cans to arrive.

Another observation was that whenever every speaker wanted to start 
his/her presentation, it would take a few minutes to setup their laptops 
as they would be connected to the vga cable on stage. Instead of all 
this wiring, is it possible to use the wireless LAN to broadcast the 
video-out directly to the projector through a receiver interface? What 
would be needed is a small application ( which can become a default in 
future distros ) in the laptop that compresses the video-out and sends 
it out through the wLAN to the hall's internal computer which then sends 
it to the projector. So every speaker simply clicks the application 
button in the laptop to start broadcasting. This will also give total 
wireless freedom for the speakers to move with their laptops. A wLAN 
runs at 50 Mbps which means 6.25 MBytes per second which should be more 
than sufficient for compressed video streams and internet access together.

About 2 years ago I had also put forward a concept on this list, where a 
single projector is used to broadcast multiple images that can be 
selectively observed by different members of the audience. The projector 
would project image frames at high speeds. These images would be a 
combination of different video outputs from different sources. The 
members of the audience wear special LCD specs that work as a 
transparent window with a black LCD shutter. There are 2 or mode films 
being projected in multi frame sequences and the shutter in the glass 
opens only when its corresponding frame appears. So different people are 
simultaneously watching different movies in the same hall, using the 
same projector. Sound is wireless broadcast to individual headphones. 
Though this is far fetched for now, a small experiment can be carried 
out to watch at least 2 movies together. There are 2 video outputs 
available at a frame rate of 25 frames per second and each frame 
consisting of 2 fields interlaced together. So the video field frequency 
is 50 Hz. for each movie. The projector is running at 100 Hz. and it 
interlaces the 2 separate movie fields one after the other in a 
sequence. The glass shutter is yet to be developed, so a mechanical 
shutter can be used for experiments. It will be a fan blade type 
shutter, similar to the ones used in film projectors. 2 persons will 
individually view the screen through these shutters, but they will be 
phased to open only at their respective field projection and close 
during the other. So while person A is watching movie A, person B is 
watching movie B. Now if the 2 + 2 fields are polarized too, then during 
each frame session, 2 polarized fields are available. So now 4 people 
can watch 4 different movies using a combination of a shutter as well as 
polarized glasses, although with jitter. This can be reduced by 
increasing frame rate frequencies as technology advances.

Regards,

Rony.

		
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