diff --git a/ctf/org.eclipse.tracecompass.ctf.core/src/org/eclipse/tracecompass/ctf/core/trace/CTFTrace.java b/ctf/org.eclipse.tracecompass.ctf.core/src/org/eclipse/tracecompass/ctf/core/trace/CTFTrace.java
index 14555ae18a..f50c9a69dd 100644
--- a/ctf/org.eclipse.tracecompass.ctf.core/src/org/eclipse/tracecompass/ctf/core/trace/CTFTrace.java
+++ b/ctf/org.eclipse.tracecompass.ctf.core/src/org/eclipse/tracecompass/ctf/core/trace/CTFTrace.java
@@ -616,7 +616,7 @@ private StreamInputPacketIndex createIndex(File streamFile, ICTFStream stream) t
                         // skip packet as the position must be invalid.
                         continue;
                     }
-                    ByteBuffer byteBuffer = SafeMappedByteBuffer.map(fc, MapMode.READ_ONLY, (packetPosition + getPacketHeader().getMaximumSize()) / Byte.SIZE, packetContextDecl.getMaximumSize());
+                    ByteBuffer byteBuffer = SafeMappedByteBuffer.map(fc, MapMode.READ_ONLY, (packetPosition + getPacketHeader().getMaximumSize()) / Byte.SIZE, packetContextDecl.getMaximumSize() / Byte.SIZE);
                     BitBuffer bitBuffer = new BitBuffer(byteBuffer);
                     StructDefinition packetContextFromStream = packetContextDecl.createDefinition(this, ILexicalScope.PACKET_HEADER, bitBuffer);