Andrey Konovalov 05cdef27ab libcamera: pipeline: simple: enable mplane devices using contiguous memory
The current simple pipeline handler refuses to work with capture devices
which have V4L2_CAP_VIDEO_CAPTURE_MPLANE flag set in the device capabilities
field. This is too restrictive, as devices supporting the multi-planar API
can be using contiguous memory for semi-planar and planar formats, and this
would just work without any changes to libcamera.

Drop the guard against MPLANE devices, and replace it with the check of
the number of planes in the format the simple pipeline handler is going to
use for capture. This will let MPLANE devices which don't use non-contiguous
memory for frame buffers to work with the simple pipeline handler.

The following code in SimpleCameraData::init() filters out the pixel formats
libcamera doesn't support:

	PixelFormat pixelFormat = videoFormat.first.toPixelFormat();
	if (!pixelFormat)
		continue;

So the check for the number of memory planes this patch adds would not
trigger until non-contiguous planar formats becomes supported in libcamera,
and video devices using these formats are enabled in the simple pipeline
handler. Then this check will remind one to review the simple pipeline
handler code.

Signed-off-by: Andrey Konovalov <andrey.konovalov@linaro.org>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
2020-10-10 01:42:44 +03:00
2020-09-24 21:08:34 +03:00

.. SPDX-License-Identifier: CC-BY-SA-4.0

.. section-begin-libcamera

===========
 libcamera
===========

**A complex camera support library for Linux, Android, and ChromeOS**

Cameras are complex devices that need heavy hardware image processing
operations. Control of the processing is based on advanced algorithms that must
run on a programmable processor. This has traditionally been implemented in a
dedicated MCU in the camera, but in embedded devices algorithms have been moved
to the main CPU to save cost. Blurring the boundary between camera devices and
Linux often left the user with no other option than a vendor-specific
closed-source solution.

To address this problem the Linux media community has very recently started
collaboration with the industry to develop a camera stack that will be
open-source-friendly while still protecting vendor core IP. libcamera was born
out of that collaboration and will offer modern camera support to Linux-based
systems, including traditional Linux distributions, ChromeOS and Android.

.. section-end-libcamera
.. section-begin-getting-started

Getting Started
---------------

To fetch the sources, build and install:

::

  git clone git://linuxtv.org/libcamera.git
  cd libcamera
  meson build
  ninja -C build install

Dependencies
~~~~~~~~~~~~

The following Debian/Ubuntu packages are required for building libcamera.
Other distributions may have differing package names:

A C++ toolchain: [required]
	Either {g++, clang}

Meson Build system: [required]
        meson (>= 0.51) ninja-build pkg-config

        If your distribution doesn't provide a recent enough version of meson,
        you can install or upgrade it using pip3.

        .. code::

            pip3 install --user meson
            pip3 install --user --upgrade meson

for the libcamera core: [required]
        python3-yaml

for IPA module signing: [required]
        libgnutls28-dev openssl

for the Raspberry Pi IPA: [optional]
        libboost-dev

        Support for Raspberry Pi can be disabled through the meson
         'pipelines' option to avoid this dependency.

for device hotplug enumeration: [optional]
	libudev-dev

for documentation: [optional]
	python3-sphinx doxygen graphviz

for gstreamer: [optional]
	libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev

for qcam: [optional]
	qtbase5-dev libqt5core5a libqt5gui5 libqt5widgets5 qttools5-dev-tools libtiff-dev

Using GStreamer plugin
~~~~~~~~~~~~~~~~~~~~~~

To use GStreamer plugin from source tree, set the following environment so that
GStreamer can find it.

  export GST_PLUGIN_PATH=$(pwd)/build/src/gstreamer

The debugging tool `gst-launch-1.0` can be used to construct and pipeline and test
it. The following pipeline will stream from the camera named "Camera 1" onto the
default video display element on your system.

.. code::

  gst-launch-1.0 libcamerasrc camera-name="Camera 1" ! videoconvert ! autovideosink

.. section-end-getting-started
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