SAN

• Company: LucasArts

SAN stands for Smush Animation Format. It is a full motion video format used in a number of different LucasArts games. What follows are some random notes based on examining files as well as decoders from versions of the ScummVM and Residual applications which are open source reimplementations of interpreters of some of the games that used SAN.

File Format

• a chunked multimedia format possibly with several variations
• multi-byte numbers are little endian (always?)
• no: the chunk lengths are big endian
• chunks are marked by FOURCCs; known FOURCCs:
  • ANIM
  • AHDR
  • FRME
  • NPAL
  • FOBJ
  • PSAD
  • TRES
  • XPAL
  • LACT
  • STOR
  • FTCH
  • SKIP
  • STRK
  • SMRK
  • SHDR
  • SDAT
  • SAUD
  • iMUS
  • FRMT
  • TEXT
  • REGN
  • STOP
  • MAP_
  • DATA
  • ETRS
• carries a payload comprised of different chunk types
• these chunk types are known:
  • codec 1
  • codec 37
  • codec 44
  • codec 47

Codec 1: RLE Encoding

• for each line in image height:
  • 16-bit number indicates encoded line size
  • while there are still encoded data bytes for this line:
    • next byte is code
    • length = code / 2 + 1
    • if bit 0 of code is set:
      • value = next byte
      • if value is 0:
        • skip (length) pixels in output
      • else:
        • put (value) in output (length) times
    • else:
      • for each count in length:
        • value = next byte
        • if value is 0:
          • skip pixel in output
        • else:
          • put value in output

Codec 37

• assign width and height
• assign bw as block width
• assign bh as block height
• codec must operate on 4x4 blocks
• assign pitch as block width * 4 (not the same as width necessarily since block width is rounded up to nearest multiple of 4)
• assign chunk size as size of input chunk - 14
• allocate a buffer with that size
• read chunk_size bytes into new buffer
• sequence number LE_16 @ chunk[2]
• decoded size is LE_32 @ chunk[4]
• maskflags = chunk[12]
• make table with pitch and chunk_buffer[1] as index:
  • index *= 255
  • if (index + 254 < sizeof(table) / 2)
    • assert error condition
  • for i = 0..255
    • j = (i + index) * 2
    • offsettable[i] = maketable_bytes[j+1] * pitch + maketable_bytes[j]
• if (chunk[0] == 0)
• else if (chunk[0] == 1)
  • "missing opcode codec47" (?)
• else if (chunk[0] == 2)
  • ...
• else if (chunk[0] == 3)
  • ...
• else if (chunk[0] == 4)
  • ...

Codec 44

• iterate through the encoded chunk from 0 to size - 14 (?):
  • size of encoded line = next LE_16 in chunk
  • while size is not 0:
    • count = next byte
    • pixel = next byte
    • put (pixel) in output (count) times
    • if size of line is not 0 at this point:
      • count = next LE_16 + 1
      • copy (count) pixels from encoded stream to output
  • at the end of line, output buffer rewinds by one pixel (?)

Codec 47

• chunk size = size of chunk passed in minus 14 bytes
• sequence number = first LE_16 of chunk
• encoded graphic data begins at chunk + 26
• the bytes at chunk[12] and chunk[13] serve as initializers for deltabufs[0] and [1] respectively

Games That Use SAN Files And Codecs They Use

• Rebel Assault
• Rebel Assualt II
• Rebel Assault II demo (video codec 37)
• Full Throttle (video codec 37)
• The Dig (video codec 37)
• The Curse Of Monkey Island (video codec 47)
• Outlaws
• Outlaws demo (video codec 47)
• Grim Fandango demo (video codec 47)
• Grim Fandango (video codec blocky16, audio codec VIMA)
• X-Wing Alliance
• Shadows of the Empire (PC)
• Star Wars Racer
• Star Wars DroidWorks
• Indiana Jones and the Infernal Machine
• Jedi Knight: Mysteries of the Sith
• Mortimer and the Riddles of the Medallion
• Making Magic CDROM (not a game but still uses smush)
• Escape From Monkey Island apparently has Smush headers but uses bink