[EXPERIMENTAL] Generic stereo codec with index header sending single frames

api/video/video_frame_buffer.cc

Index: api/video/video_frame_buffer.cc
diff --git a/api/video/video_frame_buffer.cc b/api/video/video_frame_buffer.cc
index dd869f77475d0bd2a50f59302959a54e84012609..ddc558355d4b3e8f8c50ed7892b5ed9dd945d288 100644
--- a/api/video/video_frame_buffer.cc
+++ b/api/video/video_frame_buffer.cc
@@ -49,6 +49,18 @@ int I420BufferInterface::ChromaHeight() const {
   return (height() + 1) / 2;
 }
 
+bool I420BufferInterface::HasAlpha() const {
+  return DataA() != nullptr && StrideA() != 0;
+}
+
+const uint8_t* I420BufferInterface::DataA() const {
+  return nullptr;
+}
+
+int I420BufferInterface::StrideA() const {
+  return 0;
+}
+
 rtc::scoped_refptr<I420BufferInterface> I420BufferInterface::ToI420() {
   return this;
 }