DepthAI Python Library

Python bindings for C++ depthai-core library

Documentation

Documentation is available over at Luxonis DepthAI API

Installation

Prebuilt wheels are available in Luxonis repository Make sure pip is upgraded

python3 -m pip install -U pip
python3 -m pip install --extra-index-url https://artifacts.luxonis.com/artifactory/luxonis-python-snapshot-local/ depthai

Building from source

Dependencies

• cmake >= 3.4
• C++14 compiler (clang, gcc, msvc, ...)
• Python3

Along these, dependencies of depthai-core are also required See: depthai-core dependencies

Building

To build and install using pip:

python3 -m pip install .

Add parameter -v to see the output of the building process.

To build a wheel, execute the following

python3 -m pip wheel . -w wheelhouse

To build a shared library from source perform the following:

ℹ️ To speed up build times, use cmake --build build --parallel [num CPU cores] (CMake >= 3.12). For older versions use: Linux/macOS: cmake --build build -- -j[num CPU cores], MSVC: cmake --build build -- /MP[num CPU cores]

git submodule update --init --recursive
cmake -H. -Bbuild
cmake --build build

To specify custom Python executable to build for, use cmake -H. -Bbuild -D PYTHON_EXECUTABLE=/full/path/to/python.

Running tests

To run the tests build the library with the following options

git submodule update --init --recursive
cmake -H. -Bbuild -D DEPTHAI_PYTHON_ENABLE_TESTS=ON -D DEPTHAI_PYTHON_ENABLE_EXAMPLES=ON -D DEPTHAI_PYTHON_TEST_EXAMPLES=ON
cmake --build build

Then navigate to build folder and run ctest

cd build
ctest

To test a specific example/test with a custom timeout (in seconds) use following:

TEST_TIMEOUT=0 ctest -R "01_rgb_preview" --verbose

If TEST_TIMEOUT=0, the test will run until stopped or it ends.

Tested platforms

• Windows 10
• Ubuntu 16.04, 18.04;
• Raspbian 10;
• macOS 10.14.6, 10.15.4;

Building documentation

• Using Docker (with Docker Compose)

  cd docs
  sudo docker-compose build
  sudo docker-compose up
  

  ℹ️ You can leave out the sudo if you have added your user to the docker group (or are using rootless docker). Then open http://localhost:8000.

  This docker container will watch changes in the docs/source directory and rebuild the docs automatically

• Linux

  First, please install the required dependencies

  Then run the following commands to build the docs website

  python3 -m pip install -U pip
  python3 -m pip install -r docs/requirements.txt
  cmake -H. -Bbuild -D DEPTHAI_BUILD_DOCS=ON -D DEPTHAI_PYTHON_BUILD_DOCS=ON
  cmake --build build --target sphinx
  python3 -m http.server --bind 0.0.0.0 8000 --directory build/docs/sphinx
  

  Then open http://localhost:8000.

  This will build documentation based on current sources, so if some new changes will be made, run this command in a new terminal window to update the website source

  cmake --build build --target sphinx
  

  Then refresh your page - it should load the updated website that was just built

Troubleshooting

Relocation link error

Build failure on Ubuntu 18.04 ("relocation ..." link error) with gcc 7.4.0 (default) - issue #3

• the solution was to upgrade gcc to version 8:

  sudo apt install g++-8
  sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-8 70
  sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-8 70
  

Hunter

Hunter is a CMake-only dependency manager for C/C++ projects.

If you are stuck with error message which mentions external libraries (subdirectory of .hunter) like the following:

/usr/bin/ld: /home/[user]/.hunter/_Base/062a19a/ccfed35/a84a713/Install/lib/liblzma.a(stream_flags_decoder.c.o): warning: relocation against `lzma_footer_magic' in read-only section `.text'

Try erasing the Hunter cache folder.

Linux/MacOS:

rm -r ~/.hunter

Windows:

del C:/.hunter

or

del C:/[user]/.hunter

LTO - link time optimization

If following message appears:

lto1: internal compiler error: in add_symbol_to_partition_1, at lto/lto-partition.c:152
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-10/README.Bugs> for instructions.
lto-wrapper: fatal error: /usr/bin/c++ returned 1 exit status
compilation terminated.
/usr/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/depthai.dir/build.make:227: depthai.cpython-38-x86_64-linux-gnu.so] Error 1
make[1]: *** [CMakeFiles/Makefile2:98: CMakeFiles/depthai.dir/all] Error 2
make: *** [Makefile:130: all] Error 2

One fix is to update linker: (In case you are on Ubuntu 20.04: /usr/bin/ld --version: 2.30)

# Add to the end of /etc/apt/sources.list:

echo "deb http://ro.archive.ubuntu.com/ubuntu groovy main" >> /etc/apt/sources.list

# Replace ro with your countries local cache server (check the content of the file to find out which is)
# Not mandatory, but faster

sudo apt update
sudo apt install binutils

# Should upgrade to 2.35.1
# Check version:
/usr/bin/ld --version
# Output should be: GNU ld (GNU Binutils for Ubuntu) 2.35.1
# Revert /etc/apt/sources.list to previous state (comment out line) to prevent updating other packages.
sudo apt update

Another option is to use clang compiler:

sudo apt install clang-10
mkdir build && cd build
CC=clang-10 CXX=clang++-10 cmake ..
cmake --build . --parallel