SMPlayer Support Forum

It seems that extrastereo filter was added to ffmpeg master after the 2.8 series was branched in Sept 2015, so it will only appear in the ffmpeg git build versions. This was verified with "ffmpeg -filters" in the 2.8.5 and the git build static ffmpeg downloads in Linux. So it should work eventually, but mpv will have to be built against an ffmpeg that supports it.

I did not see any karoke filter support in either, though.

I guess they haven't updated the internal ffmpeg to support it yet either, despite what they claimed when they pulled the filter support.

I'm keeping ffmpeg up to date on Debian stable (Jessie) by backporting it from upstream Debian (it's also in jessie-backports), and then rebuilding the new mpv releases against the outside libav* ffmpeg library headers, per Debian policy to use outside shared libraries as much as possible without causing loss of features.

I've just built the latest version of mpv and now the extrastereo filter works, so I added it back to smplayer (r7337).

I see that ffmpeg-3.0, released today, now supports the extrastereo filter, so hopefully it can be backported to my stable Linux platform after it's added to upstream Debian.