diff --git a/src/AvTranscoder/properties/VideoProperties.cpp b/src/AvTranscoder/properties/VideoProperties.cpp
index 9d8e2378..97b8f4e1 100644
--- a/src/AvTranscoder/properties/VideoProperties.cpp
+++ b/src/AvTranscoder/properties/VideoProperties.cpp
@@ -432,7 +432,12 @@ int VideoProperties::getLevel() const
 
 float VideoProperties::getFps() const
 {
-    return av_q2d(_formatContext->streams[_streamIndex]->avg_frame_rate);
+    if(! _formatContext)
+        throw std::runtime_error("unknown format context");
+
+    if(_formatContext->streams[_streamIndex]->avg_frame_rate.den)
+        return av_q2d(_formatContext->streams[_streamIndex]->avg_frame_rate);
+    return av_q2d(av_inv_q(getTimeBase()));
 }
 
 float VideoProperties::getDuration() const
diff --git a/src/AvTranscoder/properties/VideoProperties.hpp b/src/AvTranscoder/properties/VideoProperties.hpp
index a5a2c9a6..27b6d0c5 100644
--- a/src/AvTranscoder/properties/VideoProperties.hpp
+++ b/src/AvTranscoder/properties/VideoProperties.hpp
@@ -64,6 +64,7 @@ class AvExport VideoProperties : public StreamProperties
 
     /**
      * @brief Corresponds to the 'fps' returned by ffprobe.
+     * @note If the average framerate is not defined in the format, return the tbn.
      * fps = the average framerate that has come from the AVStream
      * tbn = the time base in AVStream that has come from the AVStream
      * tbc = the time base in AVCodecContext for the codec used for a particular stream