sudo apt-add-repository ppa:samrog131/ppa
sudo apt-get update
sudo apt-get install ffmpeg-real
sudo ln -sf /opt/ffmpeg/bin/ffmpeg /usr/bin/ffmpeg

See http://linuxg.net/how-to-install-ffmpeg-2-4-2-on-ubuntu-14-04-linux-mint-17-elementary-os-0-3-deepin-2014-and-other-ubuntu-14-04-derivatives/

Does not pla some MP4 videos correctly (sound speed to slow!).

Is Opera considering supporting libav also?

I'm just asking because in distributions like Ubuntu that have switch to libav, it wouldn't require users to install and compile ffmpeg.

https://gist.github.com/ruario/7b33ca4cf70e6ff70880

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?

That's a Youtube video on Ubuntu 14.04 and I did compiled ffmpeg as described above.

Can you comment on the issue with VP9 on YouTube?

Opera 25.0.1597.0 on Ubuntu 14.04 does not play VP9-videos on YouTube, while Opera 25.0.1597.0 on Windows 7 (64-bit) does, as does Chrome on Ubuntu.

Opera on Ubuntu plays WebM with VP9, but not VP9 on YouTube. Can you confirm the issue?

Thanks.

2. Yeah, as avl said "most popular codec" where Opera is not able to redistribute. Where the provided solution may contain parts of GPL licensed code? Gosh, licenses...

GPL code is not the problem, and this is not related to open source vs. closed source software. The problem is that any company that distributes a product that decodes H264 video (it doesn't matter if that product is itself open source or closed source) needs to pay royalties to MPEG LA.

What’s strange is that both https://html5test.com/ and https://www.youtube.com/html5 report that proprietary codecs are supported (only with the latest build of Opera 25). I assumed Opera now used the system’s codecs (like Firefox does).

There's currently a bug (DNA-25004) which means Opera reports that it supports proprietary video formats even when the system codecs (from ffmpeg) cannot be loaded and it has to use its own. If you want to use the proprietary codecs, install ffmpeg using the instructions I gave earlier in this thread.

In any case a build coming soon will include a fix for the incorrect support entry when appropriate system libraries cannot be found.

So...

1. That Opera 25 only supports pepper (sgunhouse) is new to me. Former versions worked AFAIK (which doesn't say much...). I'll try the solution from joakimwallden or seek for some other solution. I will not install Chrome.

2. Yeah, as avl said "most popular codec" where Opera is not able to redistribute. Where the provided solution may contain parts of GPL licensed code? Gosh, licenses...

Opera 25 only recognizes "Pepper Flash", which if not available separately can be obtained by installing Chrome. (Not Chromium, Google Chrome.) No idea on HTML 5 video.

In Linux Mint, Pepper flash is available as the pepperflashplugin-nonfree package.

On Windows and Mac Opera uses the system libraries to display H264 videos, so that it doesn't have to redistribute the code itself.

On Linux there are no real 'system' libraries that are guaranteed to exist on all distros, but you can get the same result by installing the ffmpeg libraries on your system with H264 and MP3 enabled. You need ffmpeg 2.3 installed to use it with Opera, or use your distro's packages if they are available (not available on Debian-based distros, although this is expected to change in the future). Opera can't use versions of ffmpeg older than 2.3, nor the libav fork that Debian-based distros supply, because their interfaces are not binary compatible.

To compile ffmpeg yourself (the only supported way of getting H264 video in Opera developer for Linux at this moment), you can use these instructions (after downloading from http://ffmpeg.org/download.html):

$ ./configure --enable-shared --build-suffix=-ffmpeg
$ make
$ sudo make install
$ sudo ldconfig

This should give you the ffmpeg libraries installed on your system, including H264 and MP3 support.