The error appears on an ogg theora video with subtitles (video then plays sans subtitles)
Screenshot from 2013-01-16 21:20:51.png (image/png), 139.71 KB, created by Andrew Ter-Grigoryan on 2013-01-17 03:23:32 UTC
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Creator: Andrew Ter-Grigoryan
Created: 2013-01-17 03:23:32 UTC
Size: 139.71 KB
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Attachments on bug 896325: 679988