Default screengrab profile "X264 mute" works fine. But screengrab profile "X264 with audio" does not work. I found out possible bug - typo in options (in file /usr/share/kdenlive/encodingprofiles.rc) Default options for profile with audio: X264 with audio=-i pulse (...) But audio start recording with: X264 with audio=-f pulse -i default (...) Ubuntu 16.04. Kdenlive package installed from PPA.
Moved to phabricator: https://phabricator.kde.org/T9901
Commit: https://invent.kde.org/kde/kdenlive/commit/b8e8b66d4cc3cfdf8b8a86d869b7e038f7945ab4