As NVIDIA Amperium. In this case the each output buffer is also a DPB,
but using a different view layer.
Still pending a validation layer issue:
VUID-VkVideoBeginCodingInfoKHR-flags-07244
Co-authored-by: Victor Jaquez <vjaquez@igalia.com>
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6954>