Can't play or convert recorded video stream

Hi! When I open the recorded file in the player, the file plays but it is
not possible to rewind this file. When I try to convert the file to another
format, I get an error:

[matroska,webm @ 0x262e080] EBML header using unsupported features
(EBML version 0, doctype (null), doc version 0)
579642275348305700.mkv: Not yet implemented in Libav, patches welcome.

When I try to use mkvinfo, I get error:

Header EBML not found.