add tests, fix depayloader

Author: brzep

lib/ex_webrtc/rtp/h264/depayloader.ex

@@ -42,7 +42,7 @@ defmodule ExWebRTC.RTP.Depayloader.H264 do
         Resetting depayloader state. Payload: #{inspect(packet.payload)}.\
         """)
 
-        {:ok, %{depayloader | current_nal: nil, current_timestamp: nil}}
+        {nil, %{depayloader | current_timestamp: nil, fu_parser_acc: nil}}
     end
   end
 
@@ -58,27 +58,27 @@ defmodule ExWebRTC.RTP.Depayloader.H264 do
          {header, payload}
        ) do
     if fu_parser_acc != nil and current_timestamp != packet.timestamp do
-      {:error, "Invalid timestamp inside FU-A"}
-
-      Logger.debug("""
+      Logger.warning("""
       Received packet with FU-A type payload that is not a start of Fragmentation Unit with timestamp \
       different than last start and without finishing the previous FU. Dropping FU.\
       """)
-    end
 
-    case FU.parse(payload, fu_parser_acc || %FU{}) do
-      {:ok, {data, type}} ->
-        data = NAL.Header.add_header(data, 0, header.nal_ref_idc, type)
+      {:error, "Invalid timestamp inside FU-A"}
+    else
+      case FU.parse(payload, fu_parser_acc || %FU{}) do
+        {:ok, {data, type}} ->
+          data = NAL.Header.add_header(data, 0, header.nal_ref_idc, type)
 
-        {:ok,
-         {prefix_annexb(data),
-          %__MODULE__{current_timestamp: packet.timestamp, fu_parser_acc: nil}}}
+          {:ok,
+           {prefix_annexb(data),
+            %__MODULE__{current_timestamp: packet.timestamp, fu_parser_acc: nil}}}
 
-      {:incomplete, fu} ->
-        {:ok, {nil, %__MODULE__{fu_parser_acc: fu}}}
+        {:incomplete, fu} ->
+          {:ok, {nil, %__MODULE__{fu_parser_acc: fu, current_timestamp: packet.timestamp}}}
 
-      {:error, _reason} = error ->
-        error
+        {:error, _reason} = error ->
+          error
+      end
     end
   end
 
@@ -90,11 +90,11 @@ defmodule ExWebRTC.RTP.Depayloader.H264 do
   end
 
   defp handle_unit_type(unsupported_type, _depayloader, _packet, _nal) do
-    {:error, "Unsupported nal type #{unsupported_type}"}
-
-    Logger.debug("""
-      Received packet with unsupported NAL type. Supported types are: Single NALU, STAP-A, FU-A. Dropping packet.
+    Logger.warning("""
+      Received packet with unsupported NAL type: #{unsupported_type}. Supported types are: Single NALU, STAP-A, FU-A. Dropping packet.
     """)
+
+    {:error, "Unsupported nal type #{unsupported_type}"}
   end
 
   defp prefix_annexb(nal) do

test/ex_webrtc/rtp/h264/depayloader_test.exs

@@ -0,0 +1,83 @@
+defmodule ExWebRTC.RTP.H264.DepayloaderTest do
+  use ExUnit.Case, async: true
+
+  alias ExWebRTC.RTP.Depayloader
+
+  test "depayload/2" do
+    payload_stapa = <<56, 0, 1, 128, 0, 1, 129>>
+    payload_stapa_out = <<0, 0, 0, 1, 128, 0, 0, 0, 1, 129>>
+
+    payload_fuas = <<60, 133, 128>>
+    payload_fua = <<60, 5, 129>>
+    payload_fuae = <<60, 69, 130>>
+    payload_fua_out = <<0, 0, 0, 1, 37, 128, 129, 130>>
+
+    payload_single = <<53, 131>>
+    payload_single_out = <<0, 0, 0, 1, 131>>
+
+    # reserved NALu types (22, 23, 30, 31)
+    payloads_nalu_reserved = [<<55, 131>>, <<56, 131>>, <<62, 131>>, <<63, 131>>]
+    # malformed STAP-A payload. First NAL should be 1-byte long, but is 2-bytes long
+    payload_invalid = <<56, 0, 1, 128, 12, 0, 1, 129>>
+
+    depayloader = Depayloader.H264.new()
+
+    # Single NAL Unit 
+    packet = ExRTP.Packet.new(payload_single, timestamp: 123)
+
+    assert {^payload_single_out, %{current_timestamp: 123, fu_parser_acc: nil}} =
+             Depayloader.H264.depayload(depayloader, packet)
+
+    # STAP-A NAL
+    packet = ExRTP.Packet.new(payload_stapa, timestamp: 123)
+
+    assert {^payload_stapa_out, %{current_timestamp: 123, fu_parser_acc: nil}} =
+             Depayloader.H264.depayload(depayloader, packet)
+
+    # FU-A NAL
+    packet1 = ExRTP.Packet.new(payload_fuas, timestamp: 10)
+    packet2 = ExRTP.Packet.new(payload_fua, timestamp: 10)
+    packet3 = ExRTP.Packet.new(payload_fuae, timestamp: 10)
+
+    {bin, depayloader} = Depayloader.H264.depayload(depayloader, packet1)
+
+    assert {nil, %{current_timestamp: 10, fu_parser_acc: %{data: [<<128>>]}}} =
+             {bin, depayloader}
+
+    {bin, depayloader} = Depayloader.H264.depayload(depayloader, packet2)
+
+    assert {nil, %{current_timestamp: 10, fu_parser_acc: %{data: [<<129>>, <<128>>]}}} =
+             {bin, depayloader}
+
+    assert {^payload_fua_out, %{current_timestamp: 10, fu_parser_acc: nil}} =
+             Depayloader.H264.depayload(depayloader, packet3)
+
+    # Colliding timestamps in one FU-A
+    packet1 = ExRTP.Packet.new(payload_fuas, timestamp: 10)
+    packet2 = ExRTP.Packet.new(payload_fua, timestamp: 11)
+
+    {bin, depayloader} = Depayloader.H264.depayload(depayloader, packet1)
+
+    assert {nil, %{current_timestamp: 10, fu_parser_acc: %{data: [<<128>>]}}} =
+             {bin, depayloader}
+
+    {bin, depayloader} = Depayloader.H264.depayload(depayloader, packet2)
+
+    assert {nil, %{current_timestamp: nil, fu_parser_acc: nil}} =
+             {bin, depayloader}
+
+    # Check all reserved NAL types
+    Enum.map(payloads_nalu_reserved, fn payload ->
+      packet = ExRTP.Packet.new(payload, timestamp: 123)
+
+      assert {nil, %{current_timestamp: nil, fu_parser_acc: nil}} =
+               Depayloader.H264.depayload(depayloader, packet)
+    end)
+
+    # Check malformed NAL
+    packet = ExRTP.Packet.new(payload_invalid, timestamp: 123)
+
+    assert {nil, %{current_timestamp: nil, fu_parser_acc: nil}} =
+             Depayloader.H264.depayload(depayloader, packet)
+  end
+end