I downloaded using youtube-dl from https://www.dr.dk/tv/live/dr2#!/ The saved file is .flv, but it does not play with vlc/mplayer. avconv cannot convert it:$ avconv -i hl.flv hl.mp4avconv version 9.18-6:9.18-0ubuntu0.14.04.1, Copyright (c) 2000-2014 the Libav developers  built on Mar 16 2015 13:19:10 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)[flv @ 0x11d1fe0] Could not find codec parameters (Video: [0][0][0][0] / 0x0000, 2196 kb/s)[flv @ 0x11d1fe0] Could not find codec parameters (Audio: [0][0][0][0] / 0x0000, 0 channels, 128 kb/s)hl.flv: could not find codec parametersMy guess is that the codec is simply wrong and forcing the player to use the correct codec will fix this. Is there a tool that can assume the codec is wrong, and try different codecs to see if one works?
Convert video with broken codec information
video;conversion;video encoding