How the films are projected?

[manigandan srinivasan]

How a projector works can some one explain in detail ?

i have many doubts about projection and its result.

1.how sound and image are synced in projection ?

2.we shot earlier silent pictures in 14-20fps,after sound came we been shooting film in 24fps for 90 yrs almost.But,According to edison theroy 50 frames is needed to eye not sense "vision flickr".How is this problem over come in projection when we have shot only half of the frames needed to avoid vision flickr?

Pls clear this doubts in simple terms :)

[Bruce Greene]

The projector has a shutter that flashes each frame 3 times

[Brian Drysdale]

There was a recent thread more or less on this subject

 

http://www.cinematography.com/index.php?showtopic=52943&st=0&p=356446&hl=projector&fromsearch=1entry356446

 

BTW You need to use your full real name, it's one of the forum rules.

[manigandan srinivasan]

My name is manigandan sundaram :).Thanks for your answer . i posted topic abt "E.V" give ur valuable answers there it will be very useful for me

[David Mullen ASC]

Modern sound projectors have a dual-bladed shutter so that each frame is flashed twice, so 48 flashes for 24 fps. In the silent era when the projected rates were lower, many projected had triple-bladed shutters to flash each frame three times.

 

There are many sound-on-film formats, the classic one is variable area optical sound. See:

http://en.wikipedia.org/wiki/Movie_projector#Analog_Optical_Sound

 

For systems where the sound is run separately, like DTS, I believe time code is used to keep the sound in sync with the print. See:

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

[Hal Smith]

Yes, DTS uses an optical time code track on the film located between the picture image on a print and its analog sound track. That track is read into a controller that syncs the sound being played off of dedicated CD players. The time code track contains an ID code that tells the system which print or trailer is playing in the projector. An advantage of DTS is that multiple language versions of a film can all use the same print distributed with different CD's for each language.

 

Dolby Digital (SRD) uses an optical digital code located between the print's sprocket holes.

 

Sony SDDS uses an optical digital code located outside the sprocket holes.

 

All of the above plus the analog variable area soundtrack are located in different areas outside the picture area of the print. As a result, a print can have all four systems, analog optical, SRD, SDDS, and DTS, on it. Each system's information is located around twenty frames offset from the picture itself to allow for the fact that their readers are not located exactly where the picture aperture is located. That offset is standardized for each system.

 

Image of a print with all four systems on it.

[Jock Blakley]

Each system's information is located around twenty frames offset from the picture itself to allow for the fact that their readers are not located exactly where the picture aperture is located. That offset is standardized for each system.

 

Not the case for DTS - it's printed with no offset from the frame to which it is synchronised. Instead the installer measures the offset between the gate the reader and then programs the DTS playback unit to simulate the offset.

[Brad Grimmett]

My name is manigandan sundaram

OK great. Now please change your user name to your full name. It's one of the rules here.

[manigandan srinivasan]

Thank you for answers yes am using full name from now :)