[RTC-190] Add support for sprop-parameter-sets (#31)

* [RTC-190] Add support for sprop-parameter-sets * Fixes after review
membraneframework · Mar 27, 2023 · 900ee4c · 900ee4c
1 parent f62c0bb
commit 900ee4c
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diff --git a/lib/ex_sdp/attribute/fmtp.ex b/lib/ex_sdp/attribute/fmtp.ex
@@ -29,6 +29,7 @@ defmodule ExSDP.Attribute.FMTP do
                 :max_fs,
                 :max_dpb,
                 :max_br,
+                :sprop_parameter_sets,
                 # OPUS
                 :maxaveragebitrate,
                 :maxplaybackrate,
@@ -64,6 +65,7 @@ defmodule ExSDP.Attribute.FMTP do
           max_br: non_neg_integer() | nil,
           level_asymmetry_allowed: boolean() | nil,
           packetization_mode: non_neg_integer() | nil,
+          sprop_parameter_sets: %{sps: binary(), pps: binary()} | nil,
           # OPUS
           maxaveragebitrate: non_neg_integer() | nil,
           maxplaybackrate: non_neg_integer() | nil,
@@ -100,7 +102,12 @@ defmodule ExSDP.Attribute.FMTP do
   Reason of parsing failure.
   """
   @type reason ::
-          :invalid_fmtp | :invalid_pt | :string_nan | :string_not_hex | :string_not_0_nor_1
+          :invalid_fmtp
+          | :invalid_pt
+          | :invalid_sprop_parameter_sets
+          | :string_nan
+          | :string_not_hex
+          | :string_not_0_nor_1
 
   @spec parse(binary()) :: {:ok, t()} | {:error, reason()}
   def parse(fmtp) do
@@ -141,6 +148,11 @@ defmodule ExSDP.Attribute.FMTP do
          do: {rest, %{fmtp | packetization_mode: value}}
   end
 
+  defp parse_param(["sprop-parameter-sets=" <> sprop_parameter_sets | rest], fmtp) do
+    with {:ok, value} <- Utils.parse_sprop_parameter_sets(sprop_parameter_sets),
+         do: {rest, %{fmtp | sprop_parameter_sets: value}}
+  end
+
   defp parse_param(["max-mbps=" <> max_mbps | rest], fmtp) do
     with {:ok, value} <- Utils.parse_numeric_string(max_mbps),
          do: {rest, %{fmtp | max_mbps: value}}
@@ -306,6 +318,7 @@ defimpl String.Chars, for: ExSDP.Attribute.FMTP do
         Serializer.maybe_serialize("max-br", fmtp.max_br),
         Serializer.maybe_serialize("level-asymmetry-allowed", fmtp.level_asymmetry_allowed),
         Serializer.maybe_serialize("packetization-mode", fmtp.packetization_mode),
+        Serializer.maybe_serialize("sprop-parameter-sets", fmtp.sprop_parameter_sets),
         # OPUS
         Serializer.maybe_serialize("maxaveragebitrate", fmtp.maxaveragebitrate),
         Serializer.maybe_serialize("maxplaybackrate", fmtp.maxplaybackrate),

diff --git a/lib/ex_sdp/serializer.ex b/lib/ex_sdp/serializer.ex
@@ -35,6 +35,10 @@ defmodule ExSDP.Serializer do
   def maybe_serialize(type, true), do: "#{type}=1"
   def maybe_serialize(type, false), do: "#{type}=0"
   def maybe_serialize("dtmf-tones", value), do: "#{value}"
+
+  def maybe_serialize("sprop-parameter-sets", %{sps: sps, pps: pps}),
+    do: "sprop-parameter-sets=#{Base.encode64(sps)},#{Base.encode64(pps)}"
+
   def maybe_serialize(type, {key, value}), do: "#{type}=#{key}:#{value}"
   def maybe_serialize(type, value), do: "#{type}=#{value}"
 

diff --git a/lib/ex_sdp/utils.ex b/lib/ex_sdp/utils.ex
@@ -40,4 +40,27 @@ defmodule ExSDP.Utils do
       _string_not_0_nor_1 -> {:error, :string_not_0_nor_1}
     end
   end
+
+  @spec parse_sprop_parameter_sets(binary) ::
+          {:error, :invalid_sprop_parameter_sets} | {:ok, %{sps: binary, pps: binary}}
+  def parse_sprop_parameter_sets(string) do
+    result =
+      String.split(string, ",", parts: 2)
+      |> Enum.zip([:sps, :pps])
+      |> Map.new(fn {encoded, type} ->
+        decoded =
+          case Base.decode64(encoded) do
+            {:ok, decoded} -> decoded
+            :error -> nil
+          end
+
+        {type, decoded}
+      end)
+
+    if Map.get(result, :sps) && Map.get(result, :pps) do
+      {:ok, result}
+    else
+      {:error, :invalid_sprop_parameter_sets}
+    end
+  end
 end
diff --git a/test/ex_sdp/attribute/fmtp_test.exs b/test/ex_sdp/attribute/fmtp_test.exs
@@ -84,6 +84,26 @@ defmodule ExSDP.Attribute.FMTPTest do
       assert {:ok, expected} == FMTP.parse(fmtp)
     end
 
+    test "parses fmtp with sprop-parameter-sets parameters" do
+      fmtp =
+        "105 profile-level-id=64001f; packetization-mode=1; " <>
+          "sprop-parameter-sets=Z2QAH62EAQwgCGEAQwgCGEAQwgCEO1AoAt03AQEBQAAA+gAAOpgh,aO4xshs="
+
+      expected = %FMTP{
+        pt: 105,
+        profile_level_id: 0x64001F,
+        packetization_mode: 1,
+        sprop_parameter_sets: %{
+          sps:
+            <<103, 100, 0, 31, 173, 132, 1, 12, 32, 8, 97, 0, 67, 8, 2, 24, 64, 16, 194, 0, 132,
+              59, 80, 40, 2, 221, 55, 1, 1, 1, 64, 0, 0, 250, 0, 0, 58, 152, 33>>,
+          pps: <<104, 238, 49, 178, 27>>
+        }
+      }
+
+      assert {:ok, expected} == FMTP.parse(fmtp)
+    end
+
     test "returns an error when DTMF tone is too big" do
       fmtp = "100 0-15,256"
       assert {:error, :invalid_dtmf_tones} = FMTP.parse(fmtp)
@@ -139,5 +159,22 @@ defmodule ExSDP.Attribute.FMTPTest do
 
       assert "#{fmtp}" == expected
     end
+
+    test "serializes FMTP with sprop-parameter-sets" do
+      expected =
+        "fmtp:96 profile-level-id=420029;packetization-mode=1;sprop-parameter-sets=Z0IAKeKQFAe2AtwEBAaQeJEV,aM48gA=="
+
+      fmtp = %FMTP{
+        pt: 96,
+        packetization_mode: 1,
+        profile_level_id: 0x420029,
+        sprop_parameter_sets: %{
+          sps: <<103, 66, 0, 41, 226, 144, 20, 7, 182, 2, 220, 4, 4, 6, 144, 120, 145, 21>>,
+          pps: <<104, 206, 60, 128>>
+        }
+      }
+
+      assert "#{fmtp}" == expected
+    end
   end
 end