This page is based on the document 'Description of the Bink File Format' by Mike Melanson at http://multimedia.cx/bink-format.txt.
- Extenstions: bik
- Company: RAD Game Tools
- Samples: http://samples.mplayerhq.hu/game-formats/bink/, countless video games
Bink files are multimedia files used in a variety of video games, both on personal computers platforms and video game consoles. The files act as containers for data compressed with the proprietary Bink video and audio codecs. Bink multimedia files are known to bear the .bik extension.
This description is known to be incomplete.
All multi-byte numbers are stored in little endian format.
Bink files commence with a 44-byte header which is laid out as follows. Audio information follows the main header. If there are zero audio tracks, then the headers are omitted.
bytes 0-2 file signature ('BIK') byte 3 Bink Video codec revision (0x62, 0x66, 0x67, 0x68, 0x69; b,f,g,h,i respectively) bytes 4-7 file size not including the first 8 bytes bytes 8-11 number of frames bytes 12-15 largest frame size in bytes bytes 16-19 number of frames again? bytes 20-23 video width (less than or equal to 32767) bytes 24-27 video height (less than or equal to 32767) bytes 28-31 video frames per second dividend bytes 32-35 video frames per second divider bytes 36-39 video flags bits 28-31: width and height scaling 1 = 2x height doubled 2 = 2x height interlaced 3 = 2x width doubled 4 = 2x width and height-doubled 5 = 2x width and height-interlaced bytes 40-43 number of audio tracks (less than or equal to 256) for each audio track two bytes unknown two bytes audio channels (1 or 2). Not authoritative, see flags below. for each audio track two bytes audio sample rate (Hz) two bytes flags bit 15: unknown (observed in some samples) bit 14: unknown (observed in some samples) bit 13: stereo flag bit 12: Bink Audio algorithm 1 = use Bink Audio DCT 0 = use Bink Audio FFT for each audio track four bytes unknown
The audio track flags are similar to those defined for the Smacker AudioRate flags.
Following the header is a frame index table. The number of entries in the table is equal to the number of frames specified in the header. Each entry consists of a 32-bit absolute offset for that frame. There is no length information provided in the table, so the length of a sample is implicitly the difference between frame offsets, and the size of the file (for the very last frame). The absolute offset for the first entry in the table is often, but not always, offset by -1. Data for the first frame always begins immediately after the table, so the first entry in the table can be considered redundant.
Each frame contains (optional) audio and video data. Bytes 12-15 (largest frame size) probably exist to provide the playback application with the largest single buffer it will have to allocate. The layout of each frame is as follows:
for each audio track four bytes length of audio packet (bytes) plus four bytes. A value of zero indicates no audio is present for this track. four bytes number of samples in packet variable length Bink Audio packet variable length Bink Video packet
Bink data can be contained in exe files. To find where to start decoding search in the file for one of 4 id's:
'fKIB' 'gKIB' 'hKIB' 'iKIB'
Note that this is BIK value is in machine order (therefore appears backwards for x86 binaries).
Revision b is found in Heroes of Might and Magic 3, but is not supported by any of the tools published by RAD Game Tools.