diff --git a/Source/WebCore/Modules/mediasource/MediaSource.cpp b/Source/WebCore/Modules/mediasource/MediaSource.cpp
index 3a64fa09667ff..8d6990ba843c0 100644
--- a/Source/WebCore/Modules/mediasource/MediaSource.cpp
+++ b/Source/WebCore/Modules/mediasource/MediaSource.cpp
@@ -248,7 +248,7 @@ void MediaSource::monitorSourceBuffers()
     // https://dvcs.w3.org/hg/html-media/raw-file/default/media-source/media-source.html#buffer-monitoring
 
     // Note, the behavior if activeSourceBuffers is empty is undefined.
-    if (!m_activeSourceBuffers) {
+    if (!m_activeSourceBuffers || m_activeSourceBuffers->length() == 0) {
         m_private->setReadyState(MediaPlayer::HaveNothing);
         return;
     }
diff --git a/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.cpp b/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.cpp
index 3104f3771b792..0b86dba8e315b 100644
--- a/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.cpp
+++ b/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.cpp
@@ -819,7 +819,7 @@ void MediaPlayerPrivateGStreamerMSE::durationChanged()
     if (m_mediaTimeDuration != previousDuration && m_mediaTimeDuration.isValid() && previousDuration.isValid()) {
         m_player->durationChanged();
         m_playbackPipeline->notifyDurationChanged();
-        m_mediaSource->durationChanged(m_mediaTimeDuration);
+        m_mediaSource->durationChanged(durationMediaTime());
     }
 }
 
@@ -2266,7 +2266,7 @@ void MediaSourceClientGStreamerMSE::durationChanged(const MediaTime& duration)
     ASSERT(WTF::isMainThread());
 
     TRACE_MEDIA_MESSAGE("duration: %f", duration.toFloat());
-    if (!duration.isValid() || duration.isPositiveInfinite() || duration.isNegativeInfinite())
+    if (!duration.isValid() || duration.isNegativeInfinite())
         return;
 
     m_duration = duration;
@@ -2391,15 +2391,19 @@ float MediaPlayerPrivateGStreamerMSE::maxTimeSeekable() const
         return 0.0f;
 
     LOG_MEDIA_MESSAGE("maxTimeSeekable");
-    float result = duration();
-    // infinite duration means live stream
-    if (isinf(result)) {
-        MediaTime maxBufferedTime = buffered()->maximumBufferedTime();
-        // Return the highest end time reported by the buffered attribute.
-        result = maxBufferedTime.isValid() ? maxBufferedTime.toFloat() : 0;
-    }
+    return durationMediaTime().toFloat();
+}
 
-    return result;
+MediaTime MediaPlayerPrivateGStreamerMSE::durationMediaTime() const
+{
+    // Infinite duration means live stream
+    if (!m_mediaTimeDuration.isPositiveInfinite())
+        return m_mediaTimeDuration;
+
+    MediaTime maxBufferedTime = buffered()->maximumBufferedTime();
+
+    // Return the highest end time reported by the buffered attribute
+    return maxBufferedTime.isValid() ? maxBufferedTime : MediaTime::zeroTime();
 }
 
 } // namespace WebCore
diff --git a/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.h b/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.h
index 9a2ac0ddebc7f..d8a61feb0b2db 100644
--- a/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.h
+++ b/Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamerMSE.h
@@ -62,7 +62,7 @@ class MediaPlayerPrivateGStreamerMSE : public MediaPlayerPrivateGStreamer {
     bool changePipelineState(GstState) override;
 
     void durationChanged() override;
-    MediaTime durationMediaTime() const override { return m_mediaTimeDuration; }
+    MediaTime durationMediaTime() const override;
     float duration() const override;
     float mediaTimeForTimeValue(float timeValue) const;
     void setRate(float) override;