This adds a non-thread safe refcount to the GstV4l2Request. This will
allow holding on more then one request in order to implement render
delay. This is made non-thread safe for speed as we know this will all
happen on the same streaming thread.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1881>
Starting from this patch, all queue and dequeue operation happening
on V4L2 is now abstracted with the request. Buffers are dequeued
automatically when pending requests are marked done and only 1 in-flight
request is now used.
Along with fixing issues with request not being reused with slice
decoders, this change reduces the memory footprint by allocating only
two bitstream buffers.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1881>
With the asynchronous slice decoding, we only queue up to 2 slices
per frames. That side effect is that now we are dequeuing bitstream
buffers in both decoding and presentation order. This would lead to
a bitstream buffer from a previous frame being dequeued instead of
the expected last slice buffer and lead to us trying to queue an
already queued bitstream buffer.
We now fix this by tracking pending requests. As request are executed
in decoding order, we marking a request done, we can effectively
dequeue bitstream buffer from all previous request, as they have been
executed already.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1395>
The decoder is not being access from multiple threads, instead it is
always protected by the streaming lock. For this reason, a
GstAtomicQueue for the request pool is overkill and may even introduce
unneeded overhead. Use a GstQueueArray in replacement, the
GstQueueArray is a good fit since the number of item is predictable and
unlikely to vary at run-time.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1395>
The Cedrus driver would otherwise choose 1KB buffer, which is too small.
This follows what some drivers do, which is simply to use the size a
packed raw image would have. Specifications do not really guaranty any minimum
compression ratio.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1268>
This adds support for slice based decoder like the Allwinner/Cedrus driver. In
order to keep things efficient, we hold the sink buffer until we reach the end
of the picture. Note that as we don't know which one is last, we lazy queue the
slices. This effectively introduces one slice latency.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1268>
This code add required mechanism to try and allocate (not implemented yet)
otherwise wait for more buffers. This also comes with mechanism to terminate
the wait on flush or PAUSED_TO_READY transitions.
This allow negotiating the output format through caps. Some drivers can
pipeline the decoder buffer through an image processor. This only support
colorspace conversion for now.
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..
