README.rst - chromiumos/third_party/libcamera - Git at Google

 .. 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 https://git.libcamera.org/libcamera/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 (>= 0.53) ninja-build pkg-config

         meson (>= 0.55) is required for building Android (-Dandroid=enabled)

         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 python3-ply python3-jinja2

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

 for improved debugging: [optional]
         libdw-dev libunwind-dev

         libdw and libunwind provide backtraces to help debugging assertion
         failures. Their functions overlap, libdw provides the most detailed
         information, and libunwind is not needed if both libdw and the glibc
         backtrace() function are available.

 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 texlive-latex-extra

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

 for cam: [optional]
         libevent-dev

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

 for tracing with lttng: [optional]
         liblttng-ust-dev python3-jinja2 lttng-tools

 for android: [optional]
         libexif-dev libjpeg-dev libyaml-dev

 for lc-compliance: [optional]
         libevent-dev

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

 To use GStreamer plugin from source tree, set the following environment so that
 GStreamer can find it. This isn't necessary when libcamera is installed.

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

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

 .. code::

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

 To show the first camera found you can omit the camera-name property, or you
 can list the cameras and their capabilities using:

 .. code::

   gst-device-monitor-1.0 Video

 This will also show the supported stream sizes which can be manually selected
 if desired with a pipeline such as:

 .. code::

   gst-launch-1.0 libcamerasrc ! 'video/x-raw,width=1280,height=720' ! \
         glimagesink

 The libcamerasrc element has two log categories, named libcamera-provider (for
 the video device provider) and libcamerasrc (for the operation of the camera).
 All corresponding debug messages can be enabled by setting the ``GST_DEBUG``
 environment variable to ``libcamera*:7``.

 Presently, to prevent element negotiation failures it is required to specify
 the colorimetry and framerate as part of your pipeline construction. For
 instance, to capture and encode as a JPEG stream and receive on another device
 the following example could be used as a starting point:

 .. code::

    gst-launch-1.0 libcamerasrc ! \
         video/x-raw,colorimetry=bt709,format=NV12,width=1280,height=720,framerate=30/1 ! \
         jpegenc ! multipartmux ! \
         tcpserversink host=0.0.0.0 port=5000

 Which can be received on another device over the network with:

 .. code::

    gst-launch-1.0 tcpclientsrc host=$DEVICE_IP port=5000 ! \
         multipartdemux ! jpegdec ! autovideosink

 .. section-end-getting-started

 Troubleshooting
 ~~~~~~~~~~~~~~~

 Several users have reported issues with meson installation, crux of the issue
 is a potential version mismatch between the version that root uses, and the
 version that the normal user uses. On calling `ninja -C build`, it can't find
 the build.ninja module. This is a snippet of the error message.

 ::

   ninja: Entering directory `build'
   ninja: error: loading 'build.ninja': No such file or directory

 This can be solved in two ways:

 1) Don't install meson again if it is already installed system-wide.

 2) If a version of meson which is different from the system-wide version is
 already installed, uninstall that meson using pip3, and install again without
 the --user argument.
	.. 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 https://git.libcamera.org/libcamera/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 (>= 0.53) ninja-build pkg-config

	meson (>= 0.55) is required for building Android (-Dandroid=enabled)

	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 python3-ply python3-jinja2

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

	for improved debugging: [optional]
	libdw-dev libunwind-dev

	libdw and libunwind provide backtraces to help debugging assertion
	failures. Their functions overlap, libdw provides the most detailed
	information, and libunwind is not needed if both libdw and the glibc
	backtrace() function are available.

	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 texlive-latex-extra

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

	for cam: [optional]
	libevent-dev

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

	for tracing with lttng: [optional]
	liblttng-ust-dev python3-jinja2 lttng-tools

	for android: [optional]
	libexif-dev libjpeg-dev libyaml-dev

	for lc-compliance: [optional]
	libevent-dev

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

	To use GStreamer plugin from source tree, set the following environment so that
	GStreamer can find it. This isn't necessary when libcamera is installed.

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

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

	.. code::

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

	To show the first camera found you can omit the camera-name property, or you
	can list the cameras and their capabilities using:

	.. code::

	gst-device-monitor-1.0 Video

	This will also show the supported stream sizes which can be manually selected
	if desired with a pipeline such as:

	.. code::

	gst-launch-1.0 libcamerasrc ! 'video/x-raw,width=1280,height=720' ! \
	glimagesink

	The libcamerasrc element has two log categories, named libcamera-provider (for
	the video device provider) and libcamerasrc (for the operation of the camera).
	All corresponding debug messages can be enabled by setting the ``GST_DEBUG``
	environment variable to ``libcamera*:7``.

	Presently, to prevent element negotiation failures it is required to specify
	the colorimetry and framerate as part of your pipeline construction. For
	instance, to capture and encode as a JPEG stream and receive on another device
	the following example could be used as a starting point:

	.. code::

	gst-launch-1.0 libcamerasrc ! \
	video/x-raw,colorimetry=bt709,format=NV12,width=1280,height=720,framerate=30/1 ! \
	jpegenc ! multipartmux ! \
	tcpserversink host=0.0.0.0 port=5000

	Which can be received on another device over the network with:

	.. code::

	gst-launch-1.0 tcpclientsrc host=$DEVICE_IP port=5000 ! \
	multipartdemux ! jpegdec ! autovideosink

	.. section-end-getting-started

	Troubleshooting
	~~~~~~~~~~~~~~~

	Several users have reported issues with meson installation, crux of the issue
	is a potential version mismatch between the version that root uses, and the
	version that the normal user uses. On calling `ninja -C build`, it can't find
	the build.ninja module. This is a snippet of the error message.

	::

	ninja: Entering directory `build'
	ninja: error: loading 'build.ninja': No such file or directory

	This can be solved in two ways:

	1) Don't install meson again if it is already installed system-wide.

	2) If a version of meson which is different from the system-wide version is
	already installed, uninstall that meson using pip3, and install again without
	the --user argument.