ffoutput usage
The ffoutput program is provided for convenience, so that users of Blackmagic DeckLink cards may play any video supported by ffmpeg via the card. ffoutput is simply a wrapper around ffmpeg that captures the output audio and video streams. Usage goes something like this:
ffoutput -i some_file.mov: will play the file some_file.mov on the first DeckLink card present in the system. All command line arguments will be passed through to ffmpeg (i.e. -f, -vf, ...), but passing any output-related arguments will probably result in failure.
Important note: Due to some apparent quirks in the DeckLink API, ffoutput outputs audio via ALSA's aplay utility instead of via the DeckLink card. So audio output should be from the default sound card on your machine. It isn't possible at this time to pass options through to aplay (though audio decoding still occurs via ffmpeg, so audio-related ffmpeg options will have an effect.)