doc/bitstream_filters: amend name of some bitstream filters
lavfi: port perspective filter from libmpcodecs

Signed-off-by: Paul B Mahol <onemda@gmail.com>
lavfi/mp: remove mp=perspective

The filter was ported to a native libavfilter filter.

Signed-off-by: Paul B Mahol <onemda@gmail.com>
lavfi/drawutils: set subsampling for rgb too

Otherwise it is incorrectly set to 1.

Signed-off-by: Paul B Mahol <onemda@gmail.com>
fate: fix stereo3d

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>