lavf/tee: add support for bitstream filtering

This allows to apply different bitstream filters to different outputs,
with no need to transcode.
ffv1enc: check for malloc failure

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ffv1enc: propagate error code from write_extradata()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
ffv1: update years in header

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