gstreamer/subprojects/gst-plugins-bad/sys/v4l2codecs
Robert Mader f982b94cd9 v4l2codecs: decoder: Reorder caps to prefer DMA_DRM ones
Certain V4L2 fourccs don't (yet) have DRM counter parts, in which case
we can't create DMA_DRM caps for them. This is usually the case for
specific tilings, which are represented as modifiers for DMA formats.

While using these tilings is generally preferable - because of e.g.
lower memory usage - it can result in additional conversion steps when
interacting with DMA based APIs such as GL, Vulkan or KMS. In such cases
using a DMA compatible format usually ends up being the better option.

Before the addition of DMA_DRM caps, this was what playbin3 ended up
requesting in various cases - e.g. prefering NV12 over NV12_4L4 - but
the addition of DMA_DRM caps seems to confuse the selection logic.

As a simple and quite robust solution, assume that peers supporting
DMA_DRM caps always prefer these and reorder the caps accordingly.

In the future we plan to have a translation layer for cases where
there is a matching fourcc+modifier pair for a V4L2 fourcc, ensuring
optimal results.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6645>
2024-05-09 16:37:07 +00:00
..
linux
gstv4l2codecallocator.c
gstv4l2codecallocator.h
gstv4l2codecalphadecodebin.c
gstv4l2codecalphadecodebin.h
gstv4l2codecav1dec.c
gstv4l2codecav1dec.h
gstv4l2codecdevice.c
gstv4l2codecdevice.h
gstv4l2codech264dec.c
gstv4l2codech264dec.h
gstv4l2codech265dec.c
gstv4l2codech265dec.h
gstv4l2codecmpeg2dec.c
gstv4l2codecmpeg2dec.h
gstv4l2codecpool.c
gstv4l2codecpool.h
gstv4l2codecvp8dec.c
gstv4l2codecvp8dec.h
gstv4l2codecvp9dec.c
gstv4l2codecvp9dec.h
gstv4l2decoder.c
gstv4l2decoder.h
gstv4l2format.c
gstv4l2format.h
meson.build
plugin.c