CODECOPEN

This structure contains information that is used to open a CODEC. It describes the source and destination data format, as well as control and CODEC-specific information to indicate the operation of the CODEC. This structure is used on the MMIOM_CODEC_OPEN message.

typedef struct _CODECOPEN {
  ULONG     ulFlags;      /*  Commands to CODEC Proc. */
  PVOID     pControlHdr;  /*  CODEC control parameters. */
  PVOID     pSrcHdr;      /*  Source header. */
  PVOID     pDstHdr;      /*  Destination header. */
  PVOID     pOtherInfo;   /*  Pointer to MMVIDEOPEN. */
} CODECOPEN;

typedef   CODECOPEN   * PCODECOPEN ;

ulFlags (ULONG)

Contains commands to the CODEC Proc. Flags are the same as the ulCapsFlags field defined in the CODECINIFILEINFO structure. For example, if the flags CODEC_8_BIT_COLOR and CODEC_DECOMPRESS are specified, the returned instance handle will support decompression into 256 colors.

pControlHdr (PVOID)

Contains the control parameters for compression or decompression. The file I/O procedure must propagate this control information to the CODEC Proc at CODEC initialization. The information is CODEC specific, for example, Huffman parameters. If NULL, the default is assumed.

pSrcHdr (PVOID)

Contains the source header for video compression or decompression. For video, it is CODECVIDEOHEADER. See the CODECVIDEOHEADER structure for detailed information.

pDstHdr (PVOID)

Contains the destination header for compression or decompression. For video, it is CODECVIDEOHEADER.

Note: Fields not used in the structure must be set to NULL. See the CODECVIDEOHEADER structure for detailed information.

pOtherInfo (PVOID)

For video, this points to the MMVIDEOOPEN structure. This field is only used if the CODEC has the CODEC_DATA_CONSTRAINT capability specified in the ulCapsFlags field of CODECINIFILEINFO.