diff --git a/mythtv/libs/libmythtv/mpeg/mpegtables.cpp b/mythtv/libs/libmythtv/mpeg/mpegtables.cpp
index 94216f137da..90d08211253 100644
--- a/mythtv/libs/libmythtv/mpeg/mpegtables.cpp
+++ b/mythtv/libs/libmythtv/mpeg/mpegtables.cpp
@@ -717,24 +717,27 @@ uint ProgramMapTable::FindPIDs(uint           type,
 uint ProgramMapTable::FindUnusedPID(uint desired_pid)
 {
     uint pid = desired_pid;
-    while (FindPID(pid) >= 0)
+    if (pid >= MPEG_NULL_PID)
+        pid = 0x20;
+
+    while (FindPID(pid) != -1)
         pid += 0x10;
 
-    if (desired_pid <= 0x1fff)
+    if (pid < MPEG_NULL_PID)
         return pid;
 
     pid = desired_pid;
-    while (FindPID(desired_pid) >= 0)
-        desired_pid += 1;
+    while (FindPID(pid) != -1)
+        pid += 1;
 
-    if (desired_pid <= 0x1fff)
+    if (pid < MPEG_NULL_PID)
         return pid;
 
     pid = 0x20;
-    while (FindPID(desired_pid) >= 0)
-        desired_pid += 1;
+    while (FindPID(pid) != -1)
+        pid += 1;
 
-    return desired_pid & 0x1fff;
+    return pid & 0x1fff;
 }
 
 QString PSIPTable::toString(void) const
diff --git a/mythtv/libs/libmythtv/mpeg/mpegtables.h b/mythtv/libs/libmythtv/mpeg/mpegtables.h
index 82dde9115b8..4ff94017b9a 100644
--- a/mythtv/libs/libmythtv/mpeg/mpegtables.h
+++ b/mythtv/libs/libmythtv/mpeg/mpegtables.h
@@ -225,6 +225,10 @@ enum
     FREESAT_SI_PID     = 0x0f01,
     FREESAT_EIT_PID    = 0x0f02,
     FREESAT_ST_EIT_PID = 0x0f03,
+
+    /// The all-ones PID value 0x1FFF indicates a Null TS Packet
+    /// introduced to maintain a constant bit rate of a TS Multiplex.
+    MPEG_NULL_PID      = 0x1fff,
 };
 
 /** \class TableID