Add support for more scalability modes (1.5:1 resolution ratio).

Added modes:
- S2T1h
- S2T2h
- S2T3h
- S3T1h
- S3T2h
- S3T3h

Bug: webrtc:13960
Change-Id: I618a30c68b0ce1609847ee33a2298fe8fa0720c9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/273664
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Åsa Persson <asapersson@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37968}

api/video_codecs/scalability_mode.cc

@@ -62,16 +62,28 @@ absl::string_view ScalabilityModeToString(ScalabilityMode scalability_mode) {
       return "L3T3_KEY";
     case ScalabilityMode::kS2T1:
       return "S2T1";
+    case ScalabilityMode::kS2T1h:
+      return "S2T1h";
     case ScalabilityMode::kS2T2:
       return "S2T2";
+    case ScalabilityMode::kS2T2h:
+      return "S2T2h";
     case ScalabilityMode::kS2T3:
       return "S2T3";
+    case ScalabilityMode::kS2T3h:
+      return "S2T3h";
     case ScalabilityMode::kS3T1:
       return "S3T1";
+    case ScalabilityMode::kS3T1h:
+      return "S3T1h";
     case ScalabilityMode::kS3T2:
       return "S3T2";
+    case ScalabilityMode::kS3T2h:
+      return "S3T2h";
     case ScalabilityMode::kS3T3:
       return "S3T3";
+    case ScalabilityMode::kS3T3h:
+      return "S3T3h";
   }
   RTC_CHECK_NOTREACHED();
 }

api/video_codecs/scalability_mode.h

@@ -48,11 +48,17 @@ enum class ScalabilityMode : uint8_t {
   kL3T3h,
   kL3T3_KEY,
   kS2T1,
+  kS2T1h,
   kS2T2,
+  kS2T2h,
   kS2T3,
+  kS2T3h,
   kS3T1,
+  kS3T1h,
   kS3T2,
+  kS3T2h,
   kS3T3,
+  kS3T3h,
 };
 
 inline constexpr ScalabilityMode kAllScalabilityModes[] = {
@@ -80,11 +86,17 @@ inline constexpr ScalabilityMode kAllScalabilityModes[] = {
     ScalabilityMode::kL3T3h,
     ScalabilityMode::kL3T3_KEY,
     ScalabilityMode::kS2T1,
+    ScalabilityMode::kS2T1h,
     ScalabilityMode::kS2T2,
+    ScalabilityMode::kS2T2h,
     ScalabilityMode::kS2T3,
+    ScalabilityMode::kS2T3h,
     ScalabilityMode::kS3T1,
+    ScalabilityMode::kS3T1h,
     ScalabilityMode::kS3T2,
+    ScalabilityMode::kS3T2h,
     ScalabilityMode::kS3T3,
+    ScalabilityMode::kS3T3h,
     // clang-format on
 };