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Bink — TA: Kingdoms Cutscene Video

From coreprime/kbot @ 0ab97bf · Edit on GitHub

Total Annihilation: Kingdoms replaced the original game's Smacker (.zrb) cinematics with RAD Game Tools' newer Bink codec, stored as .bik. The mission intros, faction briefings and outros all ship as Bink 1 files under movies/.

Extension Used by Notes
.bik TA: Kingdoms movies/*.bik RAD Bink 1. Signature BIK + a revision byte (BIKf in TA:K).

Bink is not Smacker — it is a separate, later codec with its own DCT-based video bitstream and its own audio (Bink Audio, DCT or RDFT). kbot parses the container header natively but delegates pixel decoding to FFmpeg, which ships a Bink 1 decoder (binkvideo, binkaudio_dct/binkaudio_rdft).

Tip

Try it yourself.

kbot bik info   movies/takmission14_ph.bik          # header summary
kbot bik to-mp4 movies/takmission14_ph.bik out.mp4  # decode to MP4 (requires ffmpeg)

From Go. Use formats/bik:

import "github.com/coreprime/kbot/formats/bik"

r, _ := bik.OpenReader("movies/takmission14_ph.bik")
defer r.Close()
fmt.Println(r.Width(), r.Height(), r.FrameCount(), r.FrameRate())
_ = bik.ConvertToMP4("movies/takmission14_ph.bik", "out.mp4")

What you'll find in a TA: Kingdoms install

$ ls $(kbot ctx path)/movies/*.bik
takmission01_ph.bik  takmission14_ph.bik  takx21_dh.bik  …
$ ls $(kbot ctx path)/movies/gui/*.bik
snort4.bik  snort6.bik  …          # tiny UI stingers, often a few KB

A typical mission cinematic is 640 × 350 at 15 fps with a single 16-bit stereo audio track (~22 kHz). The movies/gui/ clips are much smaller and sometimes have odd dimensions (e.g. 124 × 101) — see the gotcha below.

Header layout (Bink 1)

All fields are little-endian. kbot reads up to and including the audio-track tables; the per-frame index and compressed bitstream are left to FFmpeg.

typedef struct {
    char   Signature[4];   // 'B','I','K', revision  (revision 'f' in TA:K)
    uint32 FileSize;       // total file size minus 8
    uint32 Frames;         // video frame count
    uint32 LargestFrame;   // size in bytes of the biggest frame
    uint32 FramesCopy;     // duplicate frame count (ignored)
    uint32 Width;
    uint32 Height;
    uint32 FPSNum;         // frame rate numerator
    uint32 FPSDen;         // frame rate denominator
    uint32 VideoFlags;     // bit 0x00100000 = alpha plane, 0x00020000 = grayscale
    uint32 NumAudioTracks;
    // if NumAudioTracks > 0:
    uint32 AudioMaxSize[NumAudioTracks];   // per-track max packet (ignored)
    struct { uint16 SampleRate; uint16 Flags; } AudioInfo[NumAudioTracks];
    uint32 AudioTrackID[NumAudioTracks];
    // followed by:
    uint32 FrameOffsets[Frames + 1];       // LSB of each offset is the keyframe flag
} BinkHeader;

Frame rate

fps = FPSNum / FPSDen. TA:K cinematics use 15 / 1. Because it is a rational pair the value can be fractional, so kbot keeps it as a float.

Audio flags (the 16-bit Flags word)

Bit Meaning
0x4000 16-bit samples (else 8-bit)
0x2000 stereo (else mono)
0x1000 DCT codec (else RDFT)

Note

The SampleRate is the literal stored value — TA:K ships 22254 Hz, not a round 22050. kbot reports it verbatim.

Conversion is decode-only

kbot bik to-mp4 invokes FFmpeg:

ffmpeg -i in.bik \
       -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2" \
       -c:v libx264 -preset fast -crf 18 \
       -c:a aac -b:a 192k \
       -y out.mp4

There is no from-mp4: no open-source Bink encoder exists, and only RAD's proprietary tools produce .bik files. The same is true of Smacker in practice — stock FFmpeg has no Smacker encoder or muxer either (see Smacker/ZRB).

Warning

Odd dimensions. Several movies/gui/*.bik clips have dimensions that are not divisible by 2 (e.g. 124 × 101). H.264 with yuv420p requires even width and height, so the converter pads up to the next even size with a pad filter rather than rescaling — no pixels are resampled, a black edge row/column is added instead.

Gotchas

  • Bink is not Smacker. Don't point kbot zrb at a .bik (or kbot bik at a .zrb); the signatures and codecs differ entirely.
  • Bink 2 (KB2) is not supported. TA:K predates Bink 2, so every shipped file is Bink 1 (BIK*). kbot rejects KB2* with a clear error.
  • Encrypted Boneyards stingers. A handful of files under boneyards/metagame/*.bik (e.g. ftuimovie2.bik) carry the .bik extension but are not Bink containers — they are scrambled/obfuscated payloads for the online metagame UI. kbot rejects them as invalid rather than guessing.

See also

  • Smacker / ZRB — the original-TA cutscene format Bink replaced.
  • HPI — the wrapper archive that ships these files.