What is 'Squeeze Mode' doing?

Pascal Parvex

Pascal Parvex

Well-known member
I did some research about the squeeze mode some cameras have, including the DVX100A. Somebody wrote in a newsgroup posting I found that the Sony 900 squeeze mode is just removing the upper and lower black bar and then interpolating, so you don't have to do it in post production. Is the DVX-100A doing the same? And why is an anamorphic adapter better?

Another question: I shoot in squeeze mode with my DVX100A and capture the footage with in-sync Blade. If I play the footage with Windows Media Player 9, it's correctly properly in 16:9 'out of the box'. But if I eport a segment of the original captured footage with Blade, to whether DV Cinema, DV NTSC or DV PAL, it's displayed as 4:3. Is there a way to set a flag before exporting that tells the Windows Media Player 9 (or other players) to stretch/display the video as 16:9 as it does with untouched footage? Is Blade just not able to handle the new squeeze mode on the A model? Because in Blade, for 16:9 display, you have to stretch the video windosw manually to get somthing like 16:9.

A final question: Is exporting a segment (with Blade) lossless or will I loose image quality, maybe even the progressive frame information?
 
Re: What is 'Squeeze Mode' doing?

Squeeze mode on the DVX is essentially doing the same thing as the XL-1. It's basically shooting in the letterbox mode, but stretching the image verically to get rid of the bars. So technically, it's lower rez than the 4x3 mode because it's using less of the chip area.

Anamorphic is superior because it uses all of the chip area to get the same anamorphic effect.
 
Re: What is 'Squeeze Mode' doing?

When you shoot in 16:9, your camcorder is cropping the top and bottom of your picture and then streches the widescreen aspect ratio onto 480 lines from 360 lines which means you're losing approximately 25% of your pixels.

The reason an anamorphic lens is so good is that it optically distorts the image before the CCD so that your camera receives all of the pixels, giving you maximum resolution.
 
Re: What is 'Squeeze Mode' doing?

Exactly.

Let's put it another way though. The squeeze mode takes the existing field of view, crops off 25%, and then stretches it to be an anamorphic widescreen image, like Eric said.

The anamorphic adapter optically takes a 33% wider image and optically squeezes it to fit on the full surface of the CCD.

So with squeeze mode, you're getting 100% of the width and 75% of the height, and using 75% of the CCD.

With the anamorphic adapter, you're getting 133% of the width and 100% of the height, and using 100% of the CCD.

Using the adapter has its own set of drawbacks, but for optical image clarity it's got significant advantages.
 
Re: What is 'Squeeze Mode' doing?

I was explaining this to someone last night. It occurred to me during the explanation that what throws EVERYONE off in understanding it is that it's called "squeeze" mode when really what it's doing is STRETCHING.
 
Re: What is 'Squeeze Mode' doing?

Indeed! The optical adapter does "squeezing", but the in-camera mode does "stretching"!

Oh well, file "squeeze" mode in there with SKIN DTL as misnamed DVX features...
 
Re: What is 'Squeeze Mode' doing?

While on this subject for the upteenth time :)

I remember someone mentioning that on the 16:9 mode records images onto the DV tapes differently than the normal mode. That is, if you cropped the top and bottom for the normal mode?

Is this true? If so, can someone direct me to some sort of source that explaines how it exactly writes to the medium?
 
Re: What is 'Squeeze Mode' doing?

Interesting. So an anamorphic lens gives you both: A 16:9 and a wider field of view.

Another question about squeezed footage: By displaying a squeezed source, are the pixels just rearranged or are parts of the image interpolated (for a second time, if the squeeeze mode is used, with no anamorphic lens)?
 
Re: What is 'Squeeze Mode' doing?

In squeeze mode the central 720x360 of the image is digitally stretched (and new pixels are created from interpolation) to fill the full 720x480 frame. It gets written to tape as 720x480, but those 480 lines are interpolated by stretching the central 360 lines up to fill 480.

16:9 mode gets written to tape identically to 4:3, except that there's a "widescreen" flag set in the data stream that tells the TV set to display the image as widescreen instead of 4:3.
 
Re: What is 'Squeeze Mode' doing?


If so, then why would anyone use the 16:9 widescreen mode, as you'd be able to crop to the exact position in post?

Unless you plan never to post process the material you've shot?
 
Re: What is 'Squeeze Mode' doing?

Are you asking "why would someone use squeeze mode" or "why would someone use letterbox mode"?
 
Re: What is 'Squeeze Mode' doing?


I'm asking why anyone would use the letterbox mode when you can shoot in normal mode and crop it in post? That is, unless you plan not to post process your video.
 
Re: What is 'Squeeze Mode' doing?

A lot of people don't seem to like letterbox. I use it fairly frequently, if for no other reason than as a composition aid. Yes you can mask and tape off your viewfinder etc., but that just seems a) silly and b) amateurish. Shooting in letterbox just shows you what you're going to get, and if you're releasing on 4:3 (like TV commercials, etc.) then it just seems to make a lot more sense. Yes you can add bars in post, and if you really want to you could add those same bars over the letterbox bars, so you don't lose anything by having shot in letterbox. And yes, if you shoot full-frame with some translucent mask then you could theoretically reposition your shot in post, but a) I've never had to do that, b) I don't want to go doing that, I'd rather finish the footage and move on, and c) I like to get it right the first time, not rely on some crutch of "I can fix it later". It's discipline that's beaten into you by cutting your teeth on Super 8 and on 35mm on an Eyemo, where you get 25 seconds before the spring runs out, and about 60 seconds before you have to re-load (with a $50 roll of film!)

For 4:3 release with a widescreen look, I use letterbox all the time.

For 16:9 release, I use a 100 with the anamorphic adapter. If I had a 100A and didn't have the anamorphic adapter, I'd probably use squeeze mode and call it a day, even though I believe the anamorphic would add substantially to the picture quality for larger screens. The anamorphic involves several compromises, whereas squeeze mode involves only one compromise. But for large-screen stuff, it's anamorphic adapter all the way...
 
Re: What is 'Squeeze Mode' doing?

Barry, I couldn't agree with you more. My personal read on this issue is that 16:9 is going to be upon us in very short order. Why? Because the major manufactors are going to be phasing out 4:3. The prices on HD sets are dropping like flys, while the quality gets better and better all the time.

I just purchased a 30inch HDTV CTR for $850 at Sams Club that has incrediable picture quality. Clients that watch material shot and edited 16:9 have a very difficult time watching 4:3 after that. I now offer my clients their final project in either 4:3 or Widescreen or both.
 
Re: What is 'Squeeze Mode' doing?

correct me if i am wrong but doesn't shooting with squeeze mode crop the footage BEFORE compression, hence being able to dedicate more information to the 360 lines actually being used and not waste anything that would be in the letterboxing anyway?
 
Re: What is 'Squeeze Mode' doing?

Everything that happens to a DV signal happens before compression. Compression is the very last thing that happens. So all gamma corrections, letterboxing, squeezing, stretching, white balance shifts, ANYTHING that happens to the signal, happens before compression.

So yes, there is the potential for slightly higher quality in both squeeze mode and letterbox mode (saving compression on the black bars). I haven't found a test yet that shows a significant difference between them, but it certainly seems that the potential is there.
 
Re: What is 'Squeeze Mode' doing?

Compared with 4:3 footage, 16:9 squeezed looks better. I don't exactly know why, seems the interpolation algorithm for Squeeze Mode is quite sophisticated. Because of this I'll stick to the Squeeze Mode for now; 4:3 has more resolution, but it does not look better, even inferior. Maybe it's because the human eye is used to see 'in Widescreen'.
 
Re: What is 'Squeeze Mode' doing?

Dedicate more information to the 360 lines...
what does that mean exactly?


correct me if i am wrong but doesn't shooting with squeeze mode crop the footage BEFORE compression, hence being able to dedicate more information to the 360 lines actually being used and not waste anything that would be in the letterboxing anyway?
 
Re: What is 'Squeeze Mode' doing?

and large screens include what....only cinema screens...or large format tvs also ...say 42 or 50".
 
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