Compare only profile & tier when matching HEVC codec.

Level asymmetry is implicitly enabled for HEVC. When comparing two
codec params to see if they match, we only compare profile & tier,
similar as H.264.

Bug: chromium:41480904
Change-Id: I9e9debdf1b34f33986da9344b9fee14071b1ed60
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/363205
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Commit-Queue: Jianlin Qiu <jianlin.qiu@intel.com>
Cr-Commit-Position: refs/heads/main@{#43069}

api/video_codecs/h265_profile_tier_level.cc

@@ -285,6 +285,24 @@ bool H265IsSameProfileTierLevel(const CodecParameterMap& params1,
          ptl1->tier == ptl2->tier && ptl1->level == ptl2->level;
 }
 
+bool H265IsSameProfile(const CodecParameterMap& params1,
+                       const CodecParameterMap& params2) {
+  const std::optional<H265ProfileTierLevel> ptl1 =
+      ParseSdpForH265ProfileTierLevel(params1);
+  const std::optional<H265ProfileTierLevel> ptl2 =
+      ParseSdpForH265ProfileTierLevel(params2);
+  return ptl1 && ptl2 && ptl1->profile == ptl2->profile;
+}
+
+bool H265IsSameTier(const CodecParameterMap& params1,
+                    const CodecParameterMap& params2) {
+  const std::optional<H265ProfileTierLevel> ptl1 =
+      ParseSdpForH265ProfileTierLevel(params1);
+  const std::optional<H265ProfileTierLevel> ptl2 =
+      ParseSdpForH265ProfileTierLevel(params2);
+  return ptl1 && ptl2 && ptl1->tier == ptl2->tier;
+}
+
 std::optional<H265Level> GetSupportedH265Level(const Resolution& resolution,
                                                float max_fps) {
   int aligned_width =

api/video_codecs/h265_profile_tier_level.h

@@ -107,11 +107,21 @@ RTC_EXPORT std::optional<H265Level> GetSupportedH265Level(
 RTC_EXPORT std::optional<H265ProfileTierLevel> ParseSdpForH265ProfileTierLevel(
     const CodecParameterMap& params);
 
-// Returns true if the parameters have the same H265 profile or neither contains
+// Returns true if the parameters have the same H265 profile/tier/level or
-// an H265 profile, otherwise false.
+// neither contains an H265 profile/tier/level, otherwise false.
 RTC_EXPORT bool H265IsSameProfileTierLevel(const CodecParameterMap& params1,
                                            const CodecParameterMap& params2);
 
+// Returns true if the parameters have the same H265 profile, or neither
+// contains an H265 profile, otherwise false.
+RTC_EXPORT bool H265IsSameProfile(const CodecParameterMap& params1,
+                                  const CodecParameterMap& params2);
+
+// Returns true if the parameters have the same H265 tier, or neither
+// contains an H265 tier, otherwise false.
+RTC_EXPORT bool H265IsSameTier(const CodecParameterMap& params1,
+                               const CodecParameterMap& params2);
+
 }  // namespace webrtc
 
 #endif  // API_VIDEO_CODECS_H265_PROFILE_TIER_LEVEL_H_

api/video_codecs/sdp_video_format.cc

@@ -119,7 +119,8 @@ bool IsSameCodecSpecific(const std::string& name1,
              AV1IsSameLevelIdx(params1, params2);
 #ifdef RTC_ENABLE_H265
     case kVideoCodecH265:
-      return H265IsSameProfileTierLevel(params1, params2) &&
+      return H265IsSameProfile(params1, params2) &&
+             H265IsSameTier(params1, params2) &&
              IsSameH265TxMode(params1, params2);
 #endif
     default:

api/video_codecs/test/h265_profile_tier_level_unittest.cc

@@ -231,8 +231,9 @@ TEST(H265ProfileTierLevel, TestProfileTierLevelCompare) {
   params2.clear();
   params1["profile-id"] = "1";
   params2["profile-id"] = "1";
-  params1["level-id"] = "93";
+  params1["level-id"] = "180";
-  params2["level-id"] = "93";
+  // Level 3.1 is not allowed for tier 1.
+  params2["level-id"] = "180";
   params1["tier-flag"] = "0";
   params2["tier-flag"] = "1";
   EXPECT_FALSE(H265IsSameProfileTierLevel(params1, params2));
@@ -247,6 +248,114 @@ TEST(H265ProfileTierLevel, TestProfileTierLevelCompare) {
   EXPECT_FALSE(H265IsSameProfileTierLevel(params1, params2));
 }
 
+TEST(H265ProfileTierLevel, TestProfileCompare) {
+  CodecParameterMap params1;
+  CodecParameterMap params2;
+
+  // None of profile-id/tier-flag/level-id is specified,
+  EXPECT_TRUE(H265IsSameProfile(params1, params2));
+
+  // Same non-empty PTL
+  params1["profile-id"] = "1";
+  params1["tier-flag"] = "0";
+  params1["level-id"] = "120";
+  params2["profile-id"] = "1";
+  params2["tier-flag"] = "0";
+  params2["level-id"] = "120";
+  EXPECT_TRUE(H265IsSameProfile(params1, params2));
+
+  // Different profiles.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "2";
+  EXPECT_FALSE(H265IsSameProfile(params1, params2));
+
+  // Different levels. We do not compare HEVC levels.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "1";
+  params1["level-id"] = "93";
+  params2["level-id"] = "183";
+  EXPECT_TRUE(H265IsSameProfile(params1, params2));
+
+  // Different tiers.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "1";
+  params1["level-id"] = "180";
+  // level 3.1 is not allowed for tier 1.
+  params2["level-id"] = "180";
+  params1["tier-flag"] = "0";
+  params2["tier-flag"] = "1";
+  EXPECT_TRUE(H265IsSameProfile(params1, params2));
+
+  // One of the CodecParameterMap is invalid.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "1";
+  params1["tier-flag"] = "0";
+  params2["tier-flag"] = "4";
+  EXPECT_FALSE(H265IsSameProfile(params1, params2));
+}
+
+TEST(H265ProfileTierLevel, TestTierCompare) {
+  CodecParameterMap params1;
+  CodecParameterMap params2;
+
+  // None of profile-id/tier-flag/level-id is specified,
+  EXPECT_TRUE(H265IsSameTier(params1, params2));
+
+  // Same non-empty PTL
+  params1["profile-id"] = "1";
+  params1["tier-flag"] = "0";
+  params1["level-id"] = "120";
+  params2["profile-id"] = "1";
+  params2["tier-flag"] = "0";
+  params2["level-id"] = "120";
+  EXPECT_TRUE(H265IsSameTier(params1, params2));
+
+  // Different profiles.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "2";
+  EXPECT_TRUE(H265IsSameTier(params1, params2));
+
+  // Different levels. We do not compare HEVC levels.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "1";
+  params1["level-id"] = "93";
+  params2["level-id"] = "183";
+  EXPECT_TRUE(H265IsSameTier(params1, params2));
+
+  // Different tiers.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "1";
+  params1["level-id"] = "180";
+  // level 3.1 is not allowed for tier 1.
+  params2["level-id"] = "180";
+  params1["tier-flag"] = "0";
+  params2["tier-flag"] = "1";
+  EXPECT_FALSE(H265IsSameTier(params1, params2));
+
+  // One of the CodecParameterMap is invalid.
+  params1.clear();
+  params2.clear();
+  params1["profile-id"] = "1";
+  params2["profile-id"] = "1";
+  params1["tier-flag"] = "0";
+  params2["tier-flag"] = "4";
+  EXPECT_FALSE(H265IsSameTier(params1, params2));
+}
+
 TEST(H265ProfileTierLevel, TestGetSupportedH265Level) {
   // Test with 720p at 30fps
   Resolution r{.width = 1280, .height = 720};

api/video_codecs/test/sdp_video_format_unittest.cc

@@ -92,7 +92,7 @@ TEST(SdpVideoFormatTest, SameCodecNameDifferentParameters) {
   EXPECT_FALSE(Sdp("H265").IsSameCodec(Sdp(
       "H265",
       Params{{"profile-id", "1"}, {"tier-flag", "1"}, {"level-id", "93"}})));
-  EXPECT_FALSE(Sdp("H265").IsSameCodec(Sdp(
+  EXPECT_TRUE(Sdp("H265").IsSameCodec(Sdp(
       "H265",
       Params{{"profile-id", "1"}, {"tier-flag", "0"}, {"level-id", "90"}})));
   EXPECT_FALSE(
@@ -107,7 +107,7 @@ TEST(SdpVideoFormatTest, SameCodecNameDifferentParameters) {
           .IsSameCodec(Sdp("H265", Params{{"profile-id", "1"},
                                           {"tier-flag", "0"},
                                           {"level-id", "120"}})));
-  EXPECT_FALSE(
+  EXPECT_TRUE(
       Sdp("H265",
           Params{{"profile-id", "1"}, {"tier-flag", "0"}, {"level-id", "93"}})
           .IsSameCodec(Sdp("H265", Params{{"profile-id", "1"},

media/base/codec.cc

@@ -122,7 +122,8 @@ bool IsSameCodecSpecific(const std::string& name1,
            AV1IsSameLevelIdx(params1, params2);
 #ifdef RTC_ENABLE_H265
   if (either_name_matches(kH265CodecName)) {
-    return webrtc::H265IsSameProfileTierLevel(params1, params2) &&
+    return webrtc::H265IsSameProfile(params1, params2) &&
+           webrtc::H265IsSameTier(params1, params2) &&
            IsSameH265TxMode(params1, params2);
   }
 #endif

media/base/codec_unittest.cc

@@ -420,8 +420,8 @@ TEST(CodecTest, TestH265CodecMatches) {
     Codec c_level_id_4 = cricket::CreateVideoCodec(95, cricket::kH265CodecName);
     c_level_id_4.params[cricket::kH265FmtpLevelId] = kLevel4;
 
-    // Does not match since different level-ids are specified.
+    // Matches since we ignore level-id when matching H.265 codecs.
-    EXPECT_FALSE(c_ptl_blank.Matches(c_level_id_4));
+    EXPECT_TRUE(c_ptl_blank.Matches(c_level_id_4));
   }
 
   {

media/engine/webrtc_video_engine.cc

@@ -1031,6 +1031,8 @@ std::vector<VideoCodecSettings> WebRtcVideoSendChannel::SelectSendVideoCodecs(
       // following the spec in https://tools.ietf.org/html/rfc6184#section-8.2.2
       // since we should limit the encode level to the lower of local and remote
       // level when level asymmetry is not allowed.
+      // For H.265, the level asymmetry is implicitly allowed. We need to make
+      // sure the encode level is set to the remote offered level.
       if (format_it->IsSameCodec(
               {remote_codec.codec.name, remote_codec.codec.params})) {
         encoders.push_back(remote_codec);