diff -up firefox-76.0.1/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp.old firefox-76.0.1/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp
--- firefox-76.0.1/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp.old	2020-05-13 14:28:26.556800474 +0200
+++ firefox-76.0.1/dom/media/platforms/ffmpeg/FFmpegVideoDecoder.cpp	2020-05-13 14:28:31.562768959 +0200
@@ -43,7 +43,7 @@ typedef int VAStatus;
 #endif
 
 // Use some extra HW frames for potential rendering lags.
-#define EXTRA_HW_FRAMES 6
+#define EXTRA_HW_FRAMES 20
 
 typedef mozilla::layers::Image Image;
 typedef mozilla::layers::PlanarYCbCrImage PlanarYCbCrImage;