Comment 3 for bug 730159

Huh? I have no idea if there's any harm, but it sounds very much like a broken program.

It may not seem important, but video editing software is riddled with problems, and this adds to the already considerable noise. Among other problems, ffmpeg failed to convert files from Ogg Theora, but the failure was accompanied by a warning message. So it would be nice if you can fix it when you can. In the mean time, can you confirm that the message is spurious? Thanks.