This structure is a generic palette and it defines a color palette of up to 256 entries. This structure is used as part of the CODECVIDEOHEADER structure.
typedef struct _GENPAL {
  ULONG     ulStartIndex;  /*  Starting RGB index. */
  ULONG     ulNumColors;   /*  Number of following entries. */
  PRGB2     prgb2Entries;  /*  256 RGB entries. */
} GENPAL;
typedef   GENPAL   * PGENPAL ;