Signed-off-by: Diego Biurrun <diego@biurrun.de>
Make the muxers/demuxers that use the field handle the default -1 in the same way as 0. This allows distinguishing an intentionally set 0 from the default value where the user hasn't set it. Signed-off-by: Martin Storsjö <martin@martin.st>
This will allow us to automatically generate manpages for them.