Re: Image Delta Compression

In comp.compression Marton Anka <marton at 03am dot com> wrote:
> A good analogy would be screenshots: let's say you're writing an email and
> you take screenshot, then take another one in 30 seconds. The difference
> would usually be very small - only a few lines added, and no parts of the
> image would move. However, you could also scroll the contents of the email
> by two lines up between the two screenshots, in which case you'd have a fair
> amount of movement to handle. Or you could drag the window you're writing
> the email in 5 pixels up and 10 to the left - again, motion to detect.

  Some time earlier this year, someone was doing work on using delta 
compression for X windows... I don't know if this is at all related to what 
you're doing (I never read the details) but you might like to look for/at 
his work.
  I suspect that the best approach will be rather similar to MPEG: Split the 
screen into small (16x16?) blocks, align them against the previous image, 
and then delta compress.

Colin Percival