@ruario Thank you so much!

After compiling and installing ffmpeg on my computer, are there any additional libraries that I need to change in order for Opera to be able to play html5 videos? Do I need to change libffmpegsumo.so? Or should that be enough?

Even though I installed ffmpeg (v. 2.4.1), Opera cannot play h.264 videos. Does this mean I should install an earlier version of ffmpeg, like v. 2.3?