This introduces the skeleton of the H264 decoder. The plugin will list the
devices and register a subclass of the GstV4L2CodecH264Dec base class. The
subclass will pick the required specific information from the GstV4L2Device
stored in the subclass structure.
This is a GstObject which will be used to hold on media and video device file
descriptor and provide abstracted ioctl calls with these descriptor. At the
moment this helper contains just enough to enumerate the supported format.
This part will be used by the plugin to register the CODEC specific elements..
Most of the features we need are very early or not expose yet in the uAPI.
Using an internal copy ensure that we everything we need is defined avoiding
to add load of checks and conditionnal code.
This introduces a GstV4L2CodecDevice structure and helper to retrieve a
list of CODEC device drivers. In order to find the device driver we
enumerate all media devices with UDEV. We then get the media controller
topology and locate a entity with function encoder or decoder and make
sure it is linked to two V4L2 IO entity pointing to the same device
node.
