minor fix in calculate bitrate

modules/highgui/src/cap_ffmpeg_impl_v2.hpp

@@ -985,9 +985,9 @@ static AVStream *icv_add_video_stream_FFMPEG(AVFormatContext *oc,
 
     /* put sample parameters */
     unsigned long long lbit_rate = static_cast<unsigned long long>(bitrate);
-    lbit_rate += (bitrate / 4);
+    lbit_rate += (bitrate / 2);
     lbit_rate = std::min(lbit_rate, static_cast<unsigned long long>(std::numeric_limits<int>::max()));
-    c->bit_rate = bitrate;
+    c->bit_rate = lbit_rate;
 
     // took advice from
     // http://ffmpeg-users.933282.n4.nabble.com/warning-clipping-1-dct-coefficients-to-127-127-td934297.html
@@ -1466,7 +1466,7 @@ void CvVideoWriter_FFMPEG::close()
         }
 
         unsigned long long lbit_rate = static_cast<unsigned long long>(c->bit_rate);
-        lbit_rate += (bitrate / 4);
+        lbit_rate += (bitrate / 2);
         lbit_rate = std::min(lbit_rate, static_cast<unsigned long long>(std::numeric_limits<int>::max()));
         c->bit_rate_tolerance = static_cast<int>(lbit_rate);