encoder: get stream info parameters

Change-Id: I5f8fb9802290974a9cc74f535ff22365b56e50c6

src/media/media_encoder.cpp

@@ -636,4 +636,18 @@ MediaEncoder::getStreamCount() const
         return 0;
 }
 
+MediaStream
+MediaEncoder::getStream(const std::string& name, int streamIdx) const
+{
+    // if streamIdx is negative, use currentStreamIdx_
+    if (streamIdx < 0)
+        streamIdx = currentStreamIdx_;
+    // make sure streamIdx is valid
+    if (getStreamCount() <= 0 || streamIdx < 0 || encoders_.size() < (unsigned)(streamIdx + 1))
+        return {};
+    auto enc = encoders_[streamIdx];
+    // TODO set firstTimestamp
+    return MediaStream(name, enc);
+}
+
 } // namespace ring

src/media/media_encoder.h

@@ -32,6 +32,7 @@
 #include "media_buffer.h"
 #include "media_codec.h"
 #include "media_device.h"
+#include "media_stream.h"
 
 #include <map>
 #include <memory>
@@ -97,6 +98,7 @@ public:
     bool useCodec(const AccountCodecInfo* codec) const noexcept;
 
     unsigned getStreamCount() const;
+    MediaStream getStream(const std::string& name, int streamIdx = -1) const;
 
 private:
     NON_COPYABLE(MediaEncoder);