Previously a DirectShow hardware encoder would get 'stuck' and couldn't
be recreated due to a strange issue with the graph filter not properly
shutting down the encoder. This would make it so that the user could
only use the encoder once, and then it wouldn't work anymore any time it
was initialized again. dshowcapture version 0.4.2 ensures that the
encoder can restart properly by manually shutting down the filter graph.
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