So, this FOSDEM certain Vittorio gave a talk about reverse engineering codecs, all materials are here. Here are my thoughts about it.
First of all, I gave a talk about similar topic once at VDD 12, it was my first and last public talk. Of course it was a fail and there was no single question asked (and mind you, VDD attendants are usually know multimedia much deeper than ordinary FOSDEM visitor). So I think it takes a lot of courage to give such talk so Vittorio did a good job here.
Now to the remarks about the presentation itself.
He calls himself a pupil of Kostya (slide 2) â€” the name is not rare so I don’t know which Kostya he meant. Definitely not me as he’s yet to show any signs he has learned something from me.
Slide 6 mentions examples of rip-off codecs and gets it wrong too. Real had some licensed codecs, RealVideo 2 is a licensed Intel rip-off of H.263 (and surprisingly Real had even one original codec, lossless audio one). Oh, and the VP family starts with VP3, before that it was Duck TrueMotion 1/2.
Categories mentioned on the next slide are rather random subsets of all video codecs out there. I’ve REd several codecs that do not belong to either category (one of them was used in Hedgewars clones called Worms BTW).
TDSC part of the talk is remarkable for two things: 5-line tool (slide 16) is something I write from heart when I’m too lazy to find the previous version of it and it actually took less time to RE it than to talk about how it was done (the main issue there was to call JPEG decoder inside TDSC decoder).
As for Canopus HQX â€” I’ve written about it years ago. Beside the profile-specific tables there’s actual decoding to be done (you know, VLCs, DCT, that kind of stuff). But large tables in binary specification fend off reverse engineers quite often.
So, it was a good introductory talk but I haven’t missed anything by not attending it.