diff --git a/lib/rtp_h264/nal_formats/stap_a.ex b/lib/rtp_h264/nal_formats/stap_a.ex
index 4c93ff4..a5868e1 100644
--- a/lib/rtp_h264/nal_formats/stap_a.ex
+++ b/lib/rtp_h264/nal_formats/stap_a.ex
@@ -44,11 +44,11 @@ defmodule Membrane.RTP.H264.StapA do
   def aggregation_unit_size(nalu), do: byte_size(nalu) + 2
 
   @spec serialize([binary], 0..1, 0..3) :: binary
-  def serialize(payloads, reserved, nri) do
+  def serialize(payloads, f, nri) do
     payloads
     |> Enum.reverse()
     |> Enum.map(&<<byte_size(&1)::16, &1::binary>>)
     |> IO.iodata_to_binary()
-    |> NAL.Header.add_header(reserved, nri, NAL.Header.encode_type(:stap_a))
+    |> NAL.Header.add_header(f, nri, NAL.Header.encode_type(:stap_a))
   end
 end
diff --git a/lib/rtp_h264/nal_header.ex b/lib/rtp_h264/nal_header.ex
index 84b30f5..676c93e 100644
--- a/lib/rtp_h264/nal_header.ex
+++ b/lib/rtp_h264/nal_header.ex
@@ -78,8 +78,8 @@ defmodule Membrane.RTP.H264.NAL.Header do
   Adds NAL header to payload
   """
   @spec add_header(binary(), 0 | 1, nri(), type()) :: binary()
-  def add_header(payload, reserved, nri, type),
-    do: <<reserved::1, nri::2, type::5>> <> payload
+  def add_header(payload, f, nri, type),
+    do: <<f::1, nri::2, type::5>> <> payload
 
   @doc """
   Parses type stored in NAL Header
diff --git a/lib/rtp_h264/payloader.ex b/lib/rtp_h264/payloader.ex
index fdff232..5140b13 100644
--- a/lib/rtp_h264/payloader.ex
+++ b/lib/rtp_h264/payloader.ex
@@ -53,8 +53,7 @@ defmodule Membrane.RTP.H264.Payloader do
         pts: 0,
         dts: 0,
         metadata: nil,
-        nri: 0,
-        reserved: 0
+        nri: 0
       }
     ]
   end
@@ -115,7 +114,7 @@ defmodule Membrane.RTP.H264.Payloader do
     metadata_match? = !stap_acc.metadata || stap_acc.pts == buffer.pts
 
     if metadata_match? and size <= state.max_payload_size do
-      <<r::1, nri::2, _type::5, _rest::binary>> = buffer.payload
+      <<_f::1, nri::2, _type::5, _rest::binary>> = buffer.payload
 
       stap_acc = %{
         stap_acc
@@ -124,8 +123,7 @@ defmodule Membrane.RTP.H264.Payloader do
           metadata: stap_acc.metadata || buffer.metadata,
           pts: buffer.pts,
           dts: buffer.dts,
-          reserved: stap_acc.reserved * r,
-          nri: min(stap_acc.nri, nri)
+          nri: max(stap_acc.nri, nri)
       }
 
       {:accept, [], %{state | stap_acc: stap_acc}}
@@ -154,7 +152,7 @@ defmodule Membrane.RTP.H264.Payloader do
           ]
 
         payloads ->
-          payload = StapA.serialize(payloads, stap_acc.reserved, stap_acc.nri)
+          payload = StapA.serialize(payloads, 0, stap_acc.nri)
 
           [
             %Buffer{