diff --git a/libavformat/dashenc.c b/libavformat/dashenc.c
index ca24015115..089a3e7b01 100644
--- a/libavformat/dashenc.c
+++ b/libavformat/dashenc.c
@@ -754,6 +754,16 @@ static int dash_flush(AVFormatContext *s, int final, int stream)
                     break;
             }
         }
+
+        if (!os->bit_rate) {
+            // calculate average bitrate of first segment
+            int64_t bitrate = (int64_t) range_length * 8 * AV_TIME_BASE / (os->max_pts - os->start_pts);
+            if (bitrate >= 0) {
+                os->bit_rate = bitrate;
+                snprintf(os->bandwidth_str, sizeof(os->bandwidth_str),
+                     " bandwidth=\"%d\"", os->bit_rate);
+            }
+        }
         add_segment(os, filename, os->start_pts, os->max_pts - os->start_pts, start_pos, range_length, index_length);
         av_log(s, AV_LOG_VERBOSE, "Representation %d media segment %d written to: %s\n", i, os->segment_index, full_path);
     }