SWF Header Format

Offset                        Value                   Meaning
----------------------------  ---------------------   ----------------------------
0x00                          0x46 = 'F'              Uncompressed
                              0x43 = 'C'              Compressed using ZLIB
                                                      (SWF 6 or later)

0x01                          0x57 = 'W'              Always 'W'

0x02                          0x53 = 'S'              Always 'S'

0x03                          0x06                    Version Number (SWF 6)
                              0x07                    Version Number (SWF 7)

0x04 - 0x07                   FileLength              FWS -> Entire file size in bytes.
                                                      CWS -> Indicate the decompressed file size
                                                             in bytes.


0x08 (bit[7:3])               nBits                   nBits need by the following four field

depend on nBits               Xmin(Signed Integer)    Xmin of Frame Size (Always 0)

depend on nBits               Xmax(Signed Integer)    Xmax of Frame Size

depend on nBits               Ymin(Signed Integer)    Ymin of Frame Size (Always 0)

depend on nBits               Ymax(Signed Integer)    Ymax of Frame Size

After Ymax (2 Bytes)          FrameRate (U16)         Desired playback rate in fps.

After FrameRate (2 Bytes)     FrameCount(U16)         Total number of frames in this SWF.