This method allow setting up the object from the currently configured format on the
device. This is useful for M2M element where input data decides the format that will
be set on capture side.

https://bugzilla.gnome.org/show_bug.cgi?id=720568

https://bugzilla.gnome.org/show_bug.cgi?id=720568

Most M2M have undefined behaviour initially when VIDIOC_G_FMT is called.

https://bugzilla.gnome.org/show_bug.cgi?id=720568

https://bugzilla.gnome.org/show_bug.cgi?id=720568

This is to allow adding a second io-mode property on M2M device like decoder so
input and output can be controlled separatly.

https://bugzilla.gnome.org/show_bug.cgi?id=720568

Nicolas Dufresne authored Jun 04, 2013 and Nicolas Dufresne committed Jan 10, 2014

This way we can activate deactivate those quirks all at once at one
place.

https://bugzilla.gnome.org/show_bug.cgi?id=720568

This is need to correctly expose capabilities on specialized devices
like decoders and encoders.

https://bugzilla.gnome.org/show_bug.cgi?id=720568

This api is in linux kernel since version 2.6.39,
and present in all version 3.

The commit that adds the API in master branch of the
linux kernel source is:
https://github.com/torvalds/linux/commit/f8f3914cf922f5f9e1d60e9e10f6fb92742907ad

v4l2 doc: "Some devices require data for each input
or output video frame to be placed in discontiguous
memory buffers"

There are newer structures 'struct v4l2_pix_format_mplane'
and 'struct v4l2_plane'.
So the pixel format is not setup with the same API when using
multi-planar.

Also for gst-v4l2, one of the difference is that in GstV4l2Meta
there are now one mem pointer for each maped plane.

When not using multi-planar, this commit takes care of keeping
the same code path than previously. So that the 2 cases are
in two different blocks triggered from V4L2_TYPE_IS_MULTIPLANAR.

Fixes bug https://bugzilla.gnome.org/show_bug.cgi?id=712754

Nicolas Dufresne authored May 29, 2013 and Nicolas Dufresne committed Nov 25, 2013

It's unfortunate to have to do this, but with the mix of tabs and space, plus all the random
indentation this header has become very hard to read.

https://bugzilla.gnome.org/show_bug.cgi?id=712754

Instead of just assuming a aspect ratio of 1/1 use VIDIOC_CROPCAP to ask
the device.
This also add a pixel-aspect-ratio property to overwrite the value from the
driver and a force-aspect-ratio property to ignore it.

https://bugzilla.gnome.org/show_bug.cgi?id=700285

This makes it possible to set any controls that can be set with
VIDIOC_S_CTRL.
The controls are set when the property is set (if the device is open)
and when the device is opened.

https://bugzilla.gnome.org/show_bug.cgi?id=698837

This can happen if other parts of the pipeline are reconfigured.
Stop streaming even for a short amount of time can be quite visible, so it
should be avoided if possible.

https://bugzilla.gnome.org/show_bug.cgi?id=700503

v4l has add a new IOCTL to export a buffer by using dmabuf.
This patch allow to use this new IOTCL if it has been defined in videodev2.h
I introduce a new IO mode (GST_V4L2_IO_DMABUF) to enable this way of working.

https://bugzilla.gnome.org/show_bug.cgi?id=693826

https://bugzilla.gnome.org/show_bug.cgi?id=690233

https://bugzilla.gnome.org/show_bug.cgi?id=687520

When nobody is using our pool, activate it ourselves.
Avoid leaking the buffer array.
Set default pool configuration with caps.
Don't keep current_caps, core does that for us now.

Use the more specialized type for the bufferpool.
Use the size from the driver as the size of the image to read.
Don't configure the pool when created. This will be done in the setup_allocation
method later or by upstream for sinks.
Remove unused properties and variables. Bufferpool sizes are now configured in
the bufferpool by the elements in the pipeline. We might want to influence the
pool size later somehow.

Rename the size variable to sizeimage and fill it with the size that has been
given to use by the v4l2 driver instead of making something up..

Remove old method, use neww _process method for the sink.
Inform the parent bufferpool class about the settings too. This is needed to let
it know about the max-buffers.
Allocate the negotiated max-buffers and initially mmap min-buffers. The idea is
that the bufferpool will allocate more when needed.
Improve debugging.
Only poll in capture mode, it does not seem to work in playback mode on this
beagleboard.

Add different transport methods to the bufferpool (MMAP and READ/WRITE)
Do more parsing of the bufferpool config.
Start and stop streaming based on the bufferpool state.
Make separate methods for getting a buffer from the pool and filling it with
data. This allows us to fill buffers from other pools too. Either use copy or
read to fill up the target buffers.
Add property to force a transfer mode in v4l2src.
Increase default number of buffers to 4.
Negotiate bufferpool and its properties in v4l2src.

Extend from GstBufferPool.
Handle the lifetime of the pool buffers correctly with the start/stop vmethods.
Map acquire and release directly to QBUF and DQBUF. We still expose an explicit
qbuf for the v4l2sink for now.

Move the details of how a buffer is rendered to the device object.

Move the details of how to capture to the device object. Remove the
v4l2src_calls.[ch] files because they are empty now.
Provide two simple methods to get and return a buffer to the device.
Also do a slow copy when the buffer is not from our pool.

Rename start and stop methods to open and close because that is what they do.
After setting the format on the device object, setup the bufferpools. Move this
code from the v4l2src_calls.c file, it is shared between source and sink.
Make new device start and stop method that merges various bits of common code
spread over several files.

We want to keep the default strides in the videoinfo. Keep the stride of the
video frames separate so that we can use both to copy a video frame and do
correct stride conversion.

Use GstVideoInfo to store the parsed caps.
Remove outsize from the caps parsing code, it's wrong because it does not use
the stride given by the driver.

Move the configuration of the framerate to where we set the other format
parameters.
Remove hack to check if the device is active.
Store streamparm in the device info.
Use some macros to access the current device configuration.
Remove some duplicate fields in src and sink and use the device configuration
instead.

Pass the caps to the set_format function and make _set_format parse the caps.
Also keep the parsed values in the v4l2object so that we can refer to them when
we want.

Keep track of the currently configured format and setting in the
v4l2object.
Pass the v4l2object to the bufferpool constructor so that the bufferpool can
know everything about the currently configured settings. This also allows us
to remove some awkward code.

When setting a format, return the bytesperline to the caller so that it can be
used to allocate buffers.

Based on a patch by Guennadi Liakhovetski.

v2: updates because I forgot to add GstTuner interface to v4l2sink
v3: update to add all possible values to norm enum

This reverts commit 9e1d419d.

Reverting this since it adds unreviewed and bad API to v4l2src
(property of type enum, with seemingly random and unsorted values).

Based on a patch by Guennadi Liakhovetski.

Expose colorbalance controls as object properties (like we do on xvimagesink).
Make them controlable.