Add intersection... functions to Configuration

lib/ex_webrtc/peer_connection/configuration.ex

@@ -163,7 +163,6 @@ defmodule ExWebRTC.PeerConnection.Configuration do
         }
 
   @enforce_keys [
-    :controlling_process,
     :ice_ip_filter,
     :audio_extensions,
     :video_extensions
@@ -486,41 +485,57 @@ defmodule ExWebRTC.PeerConnection.Configuration do
     %RTPCodecParameters{codec | payload_type: new_pt, rtcp_fbs: new_fbs, sdp_fmtp_line: new_fmtp}
   end
 
-  # @doc false
-  @spec supported_codec?(t(), RTPCodecParameters.t()) :: boolean()
-  def supported_codec?(config, codec) do
-    # This function doesn't check if rtcp-fb is supported.
-    # Instead, `supported_rtcp_fb?` has to be used to filter out
-    # rtcp-fb that are not supported.
-    # TODO: this function doesn't compare fmtp at all
-    Enum.any?(config.audio_codecs ++ config.video_codecs, fn supported_codec ->
-      # For the purposes of comparison, lowercase mime check
-      %{
-        supported_codec
-        | mime_type: String.downcase(supported_codec.mime_type),
-          rtcp_fbs: codec.rtcp_fbs,
-          sdp_fmtp_line: codec.sdp_fmtp_line
-      } == %{
-        codec
-        | mime_type: String.downcase(codec.mime_type)
-      }
+  @doc false
+  @spec intersect_codecs(t(), ExSDP.Media.t()) :: [RTPCodecParameters.t()]
+  def intersect_codecs(config, mline) do
+    # we assume that this function is called after
+    # the config was updated based on the remote SDP
+    # so the payload types should match
+    codecs = case mline.type do
+      :audio -> config.audio_codecs
+      :video -> config.video_codecs
+    end
+
+    mline
+    |> SDPUtils.get_rtp_codec_parameters()
+    |> Enum.flat_map(fn sdp_codec ->
+      codecs
+      |> Enum.find(&(
+        # as of now, we ignore sdp_fmtp_line
+        &1.mime_type == sdp_codec.mime_type and
+        &1.payload_type == sdp_codec.payload_type and
+        &1.clock_rate == sdp_codec.clock_rate and
+        &1.channels == sdp_codec.channels
+      ))
+      |> case do
+        nil -> []
+        other ->
+          fbs = Enum.filter(sdp_codec.rtcp_fbs, fn fb -> fb in other.rtcp_fbs end)
+          [%RTPCodecParameters{sdp_codec | rtcp_fbs: fbs}]
+      end
     end)
   end
 
-  # @doc false
-  # @spec supported_rtp_hdr_extension?(t(), Extmap.t(), :audio | :video) ::
-  #         boolean()
-  def supported_rtp_hdr_extension?(config, rtp_hdr_extension, media_type) do
-    supported_uris =
-      case media_type do
-        :audio -> Map.keys(config.audio_rtp_hdr_exts)
-        :video -> Map.keys(config.video_rtp_hdr_exts)
-      end
+  @doc false
+  @spec intersect_extensions(t(), ExSDP.Media.t()) :: [Extmap.t()]
+  def intersect_extensions(config, mline) do
+    extensions = case mline.type do
+      :audio -> config.audio_extensions
+      :video -> config.video_extensions
+    end
 
-    rtp_hdr_extension.uri in supported_uris
+    mline
+    |> ExSDP.get_attributes(Extmap)
+    |> Enum.flat_map(fn sdp_extension ->
+      extensions
+      |> Enum.find(&(
+        &1.id == sdp_extension.id and
+        &1.uri == sdp_extension.uri
+      ))
+      |> case do
+        nil -> []
+        _other -> [%Extmap{sdp_extension | direction: nil}]
+      end
+    end)
   end
-
-  # @doc false
-  # @spec supported_rtcp_fb?(t(), RTCPFeedback.t()) :: boolean()
-  def supported_rtcp_fb?(_config, _rtcp_fb), do: false
 end

test/ex_webrtc/peer_connection/configuration_test.exs

@@ -4,7 +4,7 @@ defmodule ExWebRTC.PeerConnection.ConfigurationTest do
   alias ExWebRTC.PeerConnection.Configuration
   alias ExWebRTC.RTPCodecParameters
 
-  alias ExSDP.Attribute.{Extmap, FMTP}
+  alias ExSDP.Attribute.{Extmap, FMTP, RTCPFeedback}
 
   @mid_uri "urn:ietf:params:rtp-hdrext:sdes:mid"
   @twcc_uri "http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01"
@@ -51,10 +51,9 @@ defmodule ExWebRTC.PeerConnection.ConfigurationTest do
 
   describe "from_options!/1" do
     test "with everything turned off" do
-      self = self()
 
       options = [
-        controlling_process: self,
+        controlling_process: self(),
         ice_servers: [],
         ice_transport_policy: :all,
         ice_ip_filter: fn _ -> true end,
@@ -68,7 +67,6 @@ defmodule ExWebRTC.PeerConnection.ConfigurationTest do
       config = Configuration.from_options!(options)
 
       assert %Configuration{
-               controlling_process: ^self,
                ice_servers: [],
                ice_transport_policy: :all,
                audio_codecs: [],
@@ -149,7 +147,6 @@ defmodule ExWebRTC.PeerConnection.ConfigurationTest do
       end)
     end
 
-    @tag :wip
     test "with defaults" do
       config = Configuration.from_options!([])
 
@@ -345,4 +342,90 @@ defmodule ExWebRTC.PeerConnection.ConfigurationTest do
       assert pt not in [100, 101, 96, 110]
     end
   end
+
+  test "intersect_codecs/2" do
+    og_config = Configuration.from_options!([
+      audio_codecs: [%{@opus_codec | payload_type: 111}],
+      video_codecs: [%{@h264_codec | payload_type: 112}, %{@vp8_codec | payload_type: 113}],
+      feedbacks: [%{type: :all, feedback: :pli}],
+      features: [:inbound_rtx]
+    ])
+
+    sdp =
+      """
+      m=audio 9 UDP/TLS/RTP/SAVPF 0
+      a=rtpmap:111 opus/48000/2
+      a=rtcp-fb:111 transport-cc
+      m=video 9 UDP/TLS/RTP/SAVPF 1
+      a=rtpmap:112 H264/90000
+      a=rtcp-fb:112 transport-cc
+      a=rtcp-fb:112 nack pli
+      a=rtpmap:115 rtx/90000
+      a=fmtp:115 apt=112
+      a=rtpmap:113 VP8/90000
+      a=rtcp-fb:113 transport-cc
+      a=rtpmap:117 VP9/90000
+      a=rtpmap:119 rtx/90000
+      a=fmtp:119 apt=117
+      """
+      |> ExSDP.parse!()
+
+    config = Configuration.update(og_config, sdp)
+
+    audio_mline = Enum.find(sdp.media, &(&1.type == :audio))
+
+    # opus should not contain any RTCP feedbacks (SDP contains TWCC, but the config does not)
+    assert [opus] = Configuration.intersect_codecs(config, audio_mline)
+    assert %RTPCodecParameters{mime_type: "audio/opus", payload_type: 111, rtcp_fbs: []} = opus
+
+    video_mline = Enum.find(sdp.media, &(&1.type == :video))
+    assert {[h264_rtx], [h264, vp8]} =
+      config
+      |> Configuration.intersect_codecs(video_mline)
+      |> Enum.split_with(&String.ends_with?(&1.mime_type, "/rtx"))
+
+    # h264 has PLI, but VP8 does not, none of the codecs has TWCC, there's no VP9 in the SDP at all
+    assert %RTPCodecParameters{mime_type: "video/VP8", payload_type: 113, rtcp_fbs: []} = vp8
+    assert %RTPCodecParameters{
+      mime_type: "video/H264",
+      payload_type: 112,
+      rtcp_fbs: [%RTCPFeedback{pt: 112, feedback_type: :pli}]
+    } = h264
+    assert %RTPCodecParameters{
+      mime_type: "video/rtx",
+      payload_type: 115,
+      rtcp_fbs: [],
+      sdp_fmtp_line: %FMTP{pt: 115, apt: 112}
+    } = h264_rtx
+  end
+
+  test "intersect_extensions/2" do
+    og_config = Configuration.from_options!([
+      header_extensions: [%{type: :all, uri: @mid_uri}, %{type: :video, uri: @twcc_uri}],
+      features: []
+    ])
+
+    sdp =
+      """
+      m=audio 9 UDP/TLS/RTP/SAVPF 0
+      a=extmap:14 urn:ietf:params:rtp-hdrext:sdes:mid
+      a=extmap:10 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
+      a=rtpmap:111 opus/48000/2
+      m=video 9 UDP/TLS/RTP/SAVPF 1
+      a=extmap:5 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
+      a=extmap:10 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
+      a=rtpmap:112 H264/90000
+      """
+      |> ExSDP.parse!()
+
+    config = Configuration.update(og_config, sdp)
+
+    audio_mline = Enum.find(sdp.media, &(&1.type == :audio))
+    assert [mid] = Configuration.intersect_extensions(config, audio_mline)
+    assert %Extmap{id: 14, uri: @mid_uri} = mid
+
+    video_mline = Enum.find(sdp.media, &(&1.type == :video))
+    assert [twcc] = Configuration.intersect_extensions(config, video_mline)
+    assert %Extmap{id: 5, uri: @twcc_uri} = twcc
+  end
 end