hbrmt 2022-6: add header payload sizes

smpte/2022_6_hbrmt.h

@@ -41,6 +41,9 @@ extern "C"
 {
 #endif
 
+#define HBRMT_HEADER_SIZE 8 /* plus timestamp and extension */
+#define HBRMT_DATA_SIZE 1376
+
 /*
  * Reminder : High Bit Rate Media Payload Header
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