1 files changed, 64 insertions, 0 deletions
diff --git a/api/video_codecs/sdp_video_format.cc b/api/video_codecs/sdp_video_format.cc
index f8901492ee..689c337ced 100644
--- a/api/video_codecs/sdp_video_format.cc
+++ b/api/video_codecs/sdp_video_format.cc
@@ -10,10 +10,57 @@
 
 #include "api/video_codecs/sdp_video_format.h"
 
+#include "absl/strings/match.h"
+#include "api/video_codecs/h264_profile_level_id.h"
+#include "api/video_codecs/video_codec.h"
+#include "api/video_codecs/vp9_profile.h"
+#include "rtc_base/checks.h"
 #include "rtc_base/strings/string_builder.h"
 
 namespace webrtc {
 
+namespace {
+
+std::string H264GetPacketizationModeOrDefault(
+    const SdpVideoFormat::Parameters& params) {
+  constexpr char kH264FmtpPacketizationMode[] = "packetization-mode";
+  const auto it = params.find(kH264FmtpPacketizationMode);
+  if (it != params.end()) {
+    return it->second;
+  }
+  // If packetization-mode is not present, default to "0".
+  // https://tools.ietf.org/html/rfc6184#section-6.2
+  return "0";
+}
+
+bool H264IsSamePacketizationMode(const SdpVideoFormat::Parameters& left,
+                                 const SdpVideoFormat::Parameters& right) {
+  return H264GetPacketizationModeOrDefault(left) ==
+         H264GetPacketizationModeOrDefault(right);
+}
+
+// Some (video) codecs are actually families of codecs and rely on parameters
+// to distinguish different incompatible family members.
+bool IsSameCodecSpecific(const SdpVideoFormat& format1,
+                         const SdpVideoFormat& format2) {
+  // The assumption when calling this function is that the two formats have the
+  // same name.
+  RTC_DCHECK(absl::EqualsIgnoreCase(format1.name, format2.name));
+
+  VideoCodecType codec_type = PayloadStringToCodecType(format1.name);
+  switch (codec_type) {
+    case kVideoCodecH264:
+      return H264IsSameProfile(format1.parameters, format2.parameters) &&
+             H264IsSamePacketizationMode(format1.parameters,
+                                         format2.parameters);
+    case kVideoCodecVP9:
+      return VP9IsSameProfile(format1.parameters, format2.parameters);
+    default:
+      return true;
+  }
+}
+}  // namespace
+
 SdpVideoFormat::SdpVideoFormat(const std::string& name) : name(name) {}
 
 SdpVideoFormat::SdpVideoFormat(const std::string& name,
@@ -37,6 +84,23 @@ std::string SdpVideoFormat::ToString() const {
   return builder.str();
 }
 
+bool SdpVideoFormat::IsSameCodec(const SdpVideoFormat& other) const {
+  // Two codecs are considered the same if the name matches (case insensitive)
+  // and certain codec-specific parameters match.
+  return absl::EqualsIgnoreCase(name, other.name) &&
+         IsSameCodecSpecific(*this, other);
+}
+
+bool SdpVideoFormat::IsCodecInList(
+    rtc::ArrayView<const webrtc::SdpVideoFormat> formats) const {
+  for (const auto& format : formats) {
+    if (IsSameCodec(format)) {
+      return true;
+    }
+  }
+  return false;
+}
+
 bool operator==(const SdpVideoFormat& a, const SdpVideoFormat& b) {
   return a.name == b.name && a.parameters == b.parameters;
 }