78e94065fc
libcamera now has the ability to use libdw and libunwind to generate backtraces, in addition to the glibc backtrace() function. libdw provides the most detailed output and is highly recommended, but is limited to parsing backtraces, it doesn't support capturing them. libunwind and backtrace() provide both features. If backtrace() is available, libunwind will not bring any improvement. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
161 lines
4.9 KiB
ReStructuredText
161 lines
4.9 KiB
ReStructuredText
.. SPDX-License-Identifier: CC-BY-SA-4.0
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.. section-begin-libcamera
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===========
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libcamera
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===========
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**A complex camera support library for Linux, Android, and ChromeOS**
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Cameras are complex devices that need heavy hardware image processing
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operations. Control of the processing is based on advanced algorithms that must
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run on a programmable processor. This has traditionally been implemented in a
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dedicated MCU in the camera, but in embedded devices algorithms have been moved
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to the main CPU to save cost. Blurring the boundary between camera devices and
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Linux often left the user with no other option than a vendor-specific
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closed-source solution.
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To address this problem the Linux media community has very recently started
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collaboration with the industry to develop a camera stack that will be
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open-source-friendly while still protecting vendor core IP. libcamera was born
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out of that collaboration and will offer modern camera support to Linux-based
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systems, including traditional Linux distributions, ChromeOS and Android.
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.. section-end-libcamera
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.. section-begin-getting-started
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Getting Started
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---------------
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To fetch the sources, build and install:
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::
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git clone https://git.libcamera.org/libcamera/libcamera.git
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cd libcamera
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meson build
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ninja -C build install
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Dependencies
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~~~~~~~~~~~~
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The following Debian/Ubuntu packages are required for building libcamera.
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Other distributions may have differing package names:
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A C++ toolchain: [required]
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Either {g++, clang}
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Meson Build system: [required]
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meson (>= 0.55) ninja-build pkg-config
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If your distribution doesn't provide a recent enough version of meson,
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you can install or upgrade it using pip3.
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.. code::
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pip3 install --user meson
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pip3 install --user --upgrade meson
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for the libcamera core: [required]
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python3-yaml python3-ply python3-jinja2
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for IPA module signing: [required]
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libgnutls28-dev openssl
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for improved debugging: [optional]
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libdw-dev libunwind-dev
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libdw and libunwind provide backtraces to help debugging assertion
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failures. Their functions overlap, libdw provides the most detailed
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information, and libunwind is not needed if both libdw and the glibc
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backtrace() function are available.
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for the Raspberry Pi IPA: [optional]
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libboost-dev
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Support for Raspberry Pi can be disabled through the meson
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'pipelines' option to avoid this dependency.
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for device hotplug enumeration: [optional]
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libudev-dev
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for documentation: [optional]
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python3-sphinx doxygen graphviz texlive-latex-extra
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for gstreamer: [optional]
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libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev
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for cam: [optional]
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libevent-dev
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for qcam: [optional]
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qtbase5-dev libqt5core5a libqt5gui5 libqt5widgets5 qttools5-dev-tools libtiff-dev
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for tracing with lttng: [optional]
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liblttng-ust-dev python3-jinja2 lttng-tools
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for android: [optional]
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libexif-dev libjpeg-dev libyaml-dev
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for lc-compliance: [optional]
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libevent-dev libgtest-dev
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Using GStreamer plugin
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~~~~~~~~~~~~~~~~~~~~~~
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To use GStreamer plugin from source tree, set the following environment so that
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GStreamer can find it. This isn't necessary when libcamera is installed.
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export GST_PLUGIN_PATH=$(pwd)/build/src/gstreamer
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The debugging tool ``gst-launch-1.0`` can be used to construct a pipeline and
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test it. The following pipeline will stream from the camera named "Camera 1"
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onto the OpenGL accelerated display element on your system.
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.. code::
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gst-launch-1.0 libcamerasrc camera-name="Camera 1" ! glimagesink
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To show the first camera found you can omit the camera-name property, or you
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can list the cameras and their capabilities using:
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.. code::
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gst-device-monitor-1.0 Video
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This will also show the supported stream sizes which can be manually selected
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if desired with a pipeline such as:
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.. code::
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gst-launch-1.0 libcamerasrc ! 'video/x-raw,width=1280,height=720' ! \
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glimagesink
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The libcamerasrc element has two log categories, named libcamera-provider (for
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the video device provider) and libcamerasrc (for the operation of the camera).
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All corresponding debug messages can be enabled by setting the ``GST_DEBUG``
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environment variable to ``libcamera*:7``.
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.. section-end-getting-started
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Troubleshooting
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~~~~~~~~~~~~~~~
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Several users have reported issues with meson installation, crux of the issue
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is a potential version mismatch between the version that root uses, and the
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version that the normal user uses. On calling `ninja -C build`, it can't find
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the build.ninja module. This is a snippet of the error message.
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::
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ninja: Entering directory `build'
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ninja: error: loading 'build.ninja': No such file or directory
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This can be solved in two ways:
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1) Don't install meson again if it is already installed system-wide.
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2) If a version of meson which is different from the system-wide version is
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already installed, uninstall that meson using pip3, and install again without
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the --user argument.
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