diff --git a/webrtc/config.cc b/webrtc/config.cc
index 70bd87068d..357f636704 100644
--- a/webrtc/config.cc
+++ b/webrtc/config.cc
@@ -39,13 +39,13 @@ std::string VideoStream::ToString() const {
   ss << ", max_bitrate_bps:" << max_bitrate_bps;
   ss << ", max_qp: " << max_qp;
 
-  ss << ", temporal_layer_thresholds_bps: {";
+  ss << ", temporal_layer_thresholds_bps: [";
   for (size_t i = 0; i < temporal_layer_thresholds_bps.size(); ++i) {
     ss << temporal_layer_thresholds_bps[i];
     if (i != temporal_layer_thresholds_bps.size() - 1)
-      ss << "}, {";
+      ss << ", ";
   }
-  ss << '}';
+  ss << ']';
 
   ss << '}';
   return ss.str();
@@ -54,13 +54,13 @@ std::string VideoStream::ToString() const {
 std::string VideoEncoderConfig::ToString() const {
   std::stringstream ss;
 
-  ss << "{streams: {";
+  ss << "{streams: [";
   for (size_t i = 0; i < streams.size(); ++i) {
     ss << streams[i].ToString();
     if (i != streams.size() - 1)
-      ss << "}, {";
+      ss << ", ";
   }
-  ss << '}';
+  ss << ']';
   ss << ", content_type: ";
   switch (content_type) {
     case kRealtimeVideo: