Jean-Baptiste Kempf

point of comparison for when you actually do the reverse engineering, because you'll need to be bit exact, or in some cases, close to bit exact.

And then you open up your disassembler, use a lot of intuition to go and figure out, you know, where the DCT is, where's entropy coding, there is a kind of

Not a rule book, but there's always a pattern of some sort.

For example, GoToMeeting, you know it will be a lot of screen codec tools.

There's also different variants.

So often, I think it was GoToMeeting 4, 5.

2, 3, 4.

Of Cineform, yeah, at the time.

Cineform, nice.

Yeah, at the time before, actually led to the open sourcing of that work.

So in parallel to doing the binary side, you obviously have samples.

In many cases, you don't have many samples.

So you have to figure out what all the different flavors are.

And you may have a Cineform, for example, is actually a collection of different approaches and toolkits within that codec because often it grows naturally.

And the hard part is finding the sample that gets you kind of somewhere to start without having to implement 10 different other things.

So start there.

I think, thankfully, at the time, I found a sample by pure chance that had a lot of flat blocks.

It was animation.

So that really helped a lot because...

it wasn't using particularly complex coding tools, et cetera, and you could kind of get somewhere and then build up and build up until you figure, hey, here's a few bits here.