+#ifdef ALLOW_NOCHROMA
+#define CHROMA h->sps.chroma_format_idc
+#else
+#define CHROMA 1
+#endif
+
+#define EXTENDED_SAR 255
+
+#define MB_TYPE_REF0 MB_TYPE_ACPRED //dirty but it fits in 16 bit
+#define MB_TYPE_8x8DCT 0x01000000
+#define IS_REF0(a) ((a) & MB_TYPE_REF0)
+#define IS_8x8DCT(a) ((a) & MB_TYPE_8x8DCT)
+
+/* NAL unit types */
+enum {
+ NAL_SLICE=1,
+ NAL_DPA,
+ NAL_DPB,
+ NAL_DPC,
+ NAL_IDR_SLICE,
+ NAL_SEI,
+ NAL_SPS,
+ NAL_PPS,
+ NAL_AUD,
+ NAL_END_SEQUENCE,
+ NAL_END_STREAM,
+ NAL_FILLER_DATA,
+ NAL_SPS_EXT,
+ NAL_AUXILIARY_SLICE=19
+};
+
+/**
+ * SEI message types
+ */
+typedef enum {
+ SEI_BUFFERING_PERIOD = 0, ///< buffering period (H.264, D.1.1)
+ SEI_TYPE_PIC_TIMING = 1, ///< picture timing
+ SEI_TYPE_USER_DATA_UNREGISTERED = 5, ///< unregistered user data
+ SEI_TYPE_RECOVERY_POINT = 6 ///< recovery point (frame # to decoder sync)
+} SEI_Type;
+
+/**
+ * pic_struct in picture timing SEI message
+ */
+typedef enum {
+ SEI_PIC_STRUCT_FRAME = 0, ///< 0: %frame
+ SEI_PIC_STRUCT_TOP_FIELD = 1, ///< 1: top field
+ SEI_PIC_STRUCT_BOTTOM_FIELD = 2, ///< 2: bottom field
+ SEI_PIC_STRUCT_TOP_BOTTOM = 3, ///< 3: top field, bottom field, in that order
+ SEI_PIC_STRUCT_BOTTOM_TOP = 4, ///< 4: bottom field, top field, in that order
+ SEI_PIC_STRUCT_TOP_BOTTOM_TOP = 5, ///< 5: top field, bottom field, top field repeated, in that order
+ SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM = 6, ///< 6: bottom field, top field, bottom field repeated, in that order
+ SEI_PIC_STRUCT_FRAME_DOUBLING = 7, ///< 7: %frame doubling
+ SEI_PIC_STRUCT_FRAME_TRIPLING = 8 ///< 8: %frame tripling
+} SEI_PicStructType;
+