Brief notes about Bink

If you play a lot of games (or maybe not that much) andd are interested in watching their FMVs you should hear about Bink sooner or later.

This is rather widespread codec in games and it’s sad we still don’t have an opensource decoder for it.

Here are some facts about it:

  • Container format seems to inherit a lot from Smacker.
  • There are two different audio codecs differing by transform.
  • Bink video is mostly static Huffman coding + vector quantisation or DCT

So, why not reimplement it?
Here are some more details about video:

  1. It employs static Huffman coding – there are 16 predefined trees which are used to decode a lot of data — the only exceptions are block coefficients. Tree definitions include only tree number and how to reorder table of symbols for current data.
  2. Almost all values are coded in bundles for several blocks at once (usually for half of a frame)
  3. 8-bit values may be encoded as independent nibbles or high nibble may have context-dependent encoding when it’s encoded with a tree number equal to the last high nibble (so you need 16+1 trees for that but who cares).

The rest will be available as it goes.

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