AESDK AE中层类型的3种取得方式

enum {
    AEGP_ObjectType_NONE = -1,
    AEGP_ObjectType_AV,            /* Includes all pre-AE 5.0 layer types (audio or video source, including adjustment layers)    */
    AEGP_ObjectType_LIGHT,
    AEGP_ObjectType_CAMERA,
    AEGP_ObjectType_TEXT,
    AEGP_ObjectType_VECTOR,

    AEGP_ObjectType_NUM_TYPES
};
typedef A_long AEGP_ObjectType;

enum {
    AEGP_ItemType_NONE,
    AEGP_ItemType_FOLDER,
    AEGP_ItemType_COMP,
    AEGP_ItemType_SOLID_defunct,    // as of AE6, solids are now just AEGP_ItemType_FOOTAGE with AEGP_FootageSignature_SOLID
    AEGP_ItemType_FOOTAGE,
    AEGP_ItemType_NUM_TYPES1
};
typedef A_short AEGP_ItemType;