This is now fixed with the same patch from Carl in ffmpeg master <http://git.videolan.org/?p=ffmpeg.git;a=commit;h=82e53b3cef924f250f928fca6348204e2ace90d8> and the 3.1 release branch <http://git.videolan.org/?p=ffmpeg.git;a=commit;h=c70b1ae93023831664588726e32f8fcd7db4250b>. 3.1.2 should be released soon.
Thank you for the report, and apologies for the breakage. - Mark PS: It is probably worth noting that there may be other issues (though less fatal than this one) when lav* is used with a non-C locale, due to use of strtod() and related locale-dependent functions. Making use of different properties of a non-C locale (such as a non-'.' decimal_point in LC_NUMERIC) should probably be considered an unsupported configuration with ffmpeg (the utility) at least, and there may be steps taken in future to make the behaviour more consistent.
