By design, unixfd is meant to be used for zero-copy and failing when the data is
not FD based memory is wanted to help debug pipelines. Though, there exists
cases, notably with RTP payloader and demuxers, where its not possible
to get all the data into FD memory through allocation queries.
To allow using unixfd for these cases, introduce a property on the unixfdsink
that enable copying the non FD data into freshly allocated memfd.
Co-authored-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8861>
