Compression (1 Viewer)

[Alexander Kuch]

I know what V compression is, but I want to know if you have an analog sony 32 inch tv that has the feature and Im watching a widesreen movie and I turn the V compression on, does it fill the whole screen or add lines of resolution into the widescreen image? Maybe I have it all wrong but, someone please explain.

 

[Allan Jayne]

Turning on V-compression keeps all of the scan lines intact but repositions them to all occupy a 16:9 shaped space within the 4:3 screen. When the TV has V-compression, the DVD player TV shape choice should be left at 16:9.

V-compression should only be used for playing "anamorphic" or "16:9 enhanced" DVD's.

The finished anamorphic DVD picture will be about the same shape and size and sharper, compared with having the DVD player TV shape as 4:3 letterbox and the TV V-compression off, or having the DVD player in any mode playing the same program as a letterboxed non-anamorphic edition (if such an edition exists) and V-compression off.

Video hints:
http://members.aol.com/ajaynejr/video.htm

 

[Citizen87645]

This has also been called "raster collapse," which is more descriptive of what is happening.

"A raster is the series of scan lines used to create an image display. All of the lines that make up a frame of video form a raster."

 

[ChrisWiggles]

anal nitpicking: the video frame is within the larger raster, as there are scans and portions of scanlines that are active raster, but not active in the image (porches, blanking, retrace etc).

In any case, raster squeeze shrinks the V-size of the raster for the best display of an anamorphic source, utilizing all the active scanlines, rather than letterboxing it.