Playback to a decklink device with a newer version of the
DeckLink SDK (14.3) stalls because the driver code calls
IDeckLinkVideoFrame::QueryInterface, which is not
implemented by ffmpeg.
This patch implements decklink_frame::QueryInterface,
so that playback works with both older (12.x) and
newer (>= 14.3) drivers.
Note: The patch still does not allow the code to compile
with DeckLink SDK 14.3 or newer, as the API has changed.
Thomas Gritzan
0cd75dbfa0