16 bit Compression options - what compression is going on

[edb]

I'm messing around with getting my sprite collections to look good with 16 bit images.  I'm experimenting with different sprite collection
16 bit compression options and am comparing those result with saving out images from TexturePacker using its dithering options
(more info at this post http://forum.unity3d.com/threads/gradient-friendy-dither-options-for-rgba-16-asset-compression.272856/)

What exactly are the compression options Reduced 16 bit, Compressed, Dithered 16 bit Alpha, Dithered 16 bit No Alpha?  And how do they correspond to TexturePacker's settings?

My guesses:
 - Reduced 16 bit-->RGBA4444 linear
 - Dithered 16 bit Alpha-->RGBA4444 FloydSteinberg Alpha
 - Dithered 16 bit No Alpha-->RGBA4444 FloydSteinberg
 - Compressed --> Unity does its normal thing, whatever that is

Am I close?  Thanks!

[unikronsoftware]

Reduced 16 bit = RGBA4444
Dithered 16 bit alpha = floyd steinberg + alpha (RGBA4444)
Dithered 16 bit no alpha = floyd steinberg (RGB565). If you don't care about alpha use this, quality is a lot better.
Compressed = DXT / ETC / PVRTC / etc.

[edb]

Thanks for the info!