diff --git a/lib/flv_tag.cpp b/lib/flv_tag.cpp
index 9d6edf09..0f85ffcf 100644
--- a/lib/flv_tag.cpp
+++ b/lib/flv_tag.cpp
@@ -930,24 +930,38 @@ JSON::Value FLV::Tag::toJSON(DTSC::Meta & metadata){
     if (tmp){
       if (tmp->getContentP("width")){
         metadata.tracks[1].width = (long long int)tmp->getContentP("width")->NumValue();
+      }else{
+        metadata.tracks[1].width = 0;
       }
       if (tmp->getContentP("height")){
         metadata.tracks[1].height = (long long int)tmp->getContentP("height")->NumValue();
+      }else{
+        metadata.tracks[1].height = 0;
       }
       if (tmp->getContentP("framerate")){
         metadata.tracks[1].fpks = (long long int)(tmp->getContentP("framerate")->NumValue() * 1000.0);
+      }else{
+        metadata.tracks[1].fpks = 0;
       }
       if (tmp->getContentP("videodatarate")){
         metadata.tracks[1].bps = (long long int)(tmp->getContentP("videodatarate")->NumValue() * 1024) / 8;
+      }else{
+        metadata.tracks[1].bps = 0;
       }
       if (tmp->getContentP("audiodatarate")){
         metadata.tracks[2].bps = (long long int)(tmp->getContentP("audiodatarate")->NumValue() * 1024) / 8;
+      }else{
+        metadata.tracks[2].bps = 0;
       }
       if (tmp->getContentP("audiosamplerate")){
         metadata.tracks[2].rate = (long long int)tmp->getContentP("audiosamplerate")->NumValue();
+      }else{
+        metadata.tracks[2].rate = 0;
       }
       if (tmp->getContentP("audiosamplesize")){
         metadata.tracks[2].size = (long long int)tmp->getContentP("audiosamplesize")->NumValue();
+      }else{
+        metadata.tracks[2].size = 0;
       }
       if (tmp->getContentP("stereo")){
         if (tmp->getContentP("stereo")->NumValue() == 1){
@@ -955,6 +969,8 @@ JSON::Value FLV::Tag::toJSON(DTSC::Meta & metadata){
         }else{
           metadata.tracks[2].channels = 1;
         }
+      }else{
+        metadata.tracks[2].channels = 1;
       }
       for (int i = 0; i < tmp->hasContent(); ++i){
         if (tmp->getContentP(i)->Indice() == "videocodecid" || tmp->getContentP(i)->Indice() == "audiocodecid" || tmp->getContentP(i)->Indice() == "width" || tmp->getContentP(i)->Indice() == "height" || tmp->getContentP(i)->Indice() == "framerate" || tmp->getContentP(i)->Indice() == "videodatarate" || tmp->getContentP(i)->Indice() == "audiodatarate" || tmp->getContentP(i)->Indice() == "audiosamplerate" || tmp->getContentP(i)->Indice() == "audiosamplesize" || tmp->getContentP(i)->Indice() == "audiochannels"){