The only meaningful difference between choose_pix_fmts and the default
code was the inclusion of an extra branch for `keep_pix_fmt` being true.
However, in this case, we either:
1. Force the specific `ofp->format` that we inherited from
ofilter_bind_ost, or if no format was set:
2. Print an empty format list
Both of these goals can be accomplished by simply moving the decision
logic to ofilter_bind_ost, to avoid setting any format list when
keep_pix_fmt is enabled. This is arguably cleaner as it moves format
selection logic to a single function. In the case of branch 1, nothing
else needs to be done as we already force the format provided in
ofp->format, if any is set. Add an assertion to verify this assumption
just in case.
(Side note: The "choose_*" family of functions are arguably misnomers,
as they should really be called "print_*" - their current behavior is to
print the relevant format lists to the `vf/af_format` filter arguments)
Signed-off-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Niklas Haas <git@haasn.dev>