hwtransfer: handle hwcontexts that don't implement frame constraints

Some ffmpeg hwcontexts do not implement frame constraints. That means
they cannot report which formats are support for given configurations.

My previous changes to make hwupload more capable relies on the
constraints to be provided to accurately describe what combinations are
supported, so we will currently see a bunch of errors failing to
configure the hwupload filter on platforms such as v4l2 SoCs with
drmprime. This doesn't break playback, but it's confusing.

To bridge the gap, this change uses the static format metadata that we
include for hwdecs to build a fake constraints struct to keep all the
other code working.

0 files changed, 0 insertions, 0 deletions