This may be a bit of a tangent, but I'll give it a quick whirl...
1.66:1 is in that awkward ratio BETWEEN TV sizes.
Films were made in many ratios, going back throughout the history of the medium. The most common are:
1.33:1 (true 4x3 full frame)
1.66:1
1.78:1 (or 1.77:1 which is true 16x9)
1.85:1
2.35:1
There are many other ratios used, particularly in the 1950s and '60s when they were experimenting with wide screen film to compete with television.
TV sets are made in only two different screen ratios:
4x3 (which is closest to 1.33:1)
16x9 (which is closest to 1.78:1)
In order to make the movies fit into these two TV sizes, the film ratio either has to be cropped off or letterboxed to maintain its full image.
For wide screen (16x9) TVs the DVD format decided to take advantage of the horizontal information available on their 480 screen lines and instead of creating the "black bars" that everyone is familiar with on the video (basically losing around 1/3 of the available video image just for those bars, they decided to allow an "anamorphic" image to be encoded on the DVD. But when an anamorphic image is displayed on standard 4x3 TV sets, the DVD player itself generates those black bars so that the image doesn't look stretched out vertically (long, skinny heads, etc).
Most movies made today are either 1.85:1 or 2.35:1, both being wide screen formats, and nearly all the studios now do the anamorphic transfers (aka "enhanced for 16x9 TV sets"). They look much better on HDTVs.
And with old movies (pre mid-1950s) the ratio is 4x3 (1.33:1) and they play full frame on standard TVs.
But some movies of that era, and even a few more recent ones, use the 1.66:1 ratio, and that creates a problem for the DVD world, and for "purist" DVD consumers. If they just do a 4x3 letterboxed image, with the small black bars at the top and bottom, they get complaints that the image is softer, not as detailed, and DVD fans wonder why they didn't make it anamorphic/enhanced? But if they do the "16x9 enhanced" image on a 1.66:1 film, they will actually CUT OFF a bit of the visual information on the top and bottom in order to make the anamorphic image display correctly. Then consumers yell that some of the image seems to be missing on certain shots, etc. And they're right.
Disney has taken a lot of crap for this both ways. Lately they've been choosing to do the 16x9 enhanced image on their 1.66:1 movies, which means some of the top and bottom are missing, and the black bars generated on your TV set are actually in the 1.78:1 ratio. That would explain why sometimes the bars look bigger on certain DVDs you have with this ratio.
"A Little Night Music" was done without "16x9 enhancement," which means they're not cutting off any of the top/bottom ratio on your screen... so the black bars look smaller and there's more screen image vertically. But this is the true, correct, and full picture image for that in-between ratio.
*sits down*
A long-winded tangent, but that's the complete explanation for the "Black Bar Blues."
"Jaws is the Citizen Kane of movies."
blocked: logan2, Diamonds3, Hamilton22