+/* BLOCK_FLAG_DISCONTINUITY: the content doesn't follow the last block, or is probably broken */
+#define BLOCK_FLAG_DISCONTINUITY 0x0001
+/* BLOCK_FLAG_TYPE_I: Intra frame */
+#define BLOCK_FLAG_TYPE_I 0x0002
+/* BLOCK_FLAG_TYPE_P: inter frame with backward reference only */
+#define BLOCK_FLAG_TYPE_P 0x0004
+/* BLOCK_FLAG_TYPE_B: inter frame with backward and forward reference */
+#define BLOCK_FLAG_TYPE_B 0x0008
+/* BLOCK_FLAG_TYPE_PB: for inter frame when you don't know the real type */
+#define BLOCK_FLAG_TYPE_PB 0x0010
+