#!/bin/bash
# When using RTSP gstreamer can provides a way lower latency then ffmpeg
# and exposes more options to tweak the connection. However, the pypi
# version of python-opencv is build without gstreamer. Thus, we need to
# build our own python wheel.

# adapted from https://github.com/opencv/opencv-python/issues/530#issuecomment-1006343643

# install gstreamer dependencies
sudo apt-get install --quiet -y --no-install-recommends \
  gstreamer1.0-gl \
  gstreamer1.0-opencv \
  gstreamer1.0-plugins-bad \
  gstreamer1.0-plugins-good \
  gstreamer1.0-plugins-ugly \
  gstreamer1.0-tools \
  libgstreamer-plugins-base1.0-dev \
  libgstreamer1.0-0 \
  libgstreamer1.0-dev 

# ffmpeg deps
sudo apt install ffmpeg libgtk2.0-dev libavformat-dev libavcodec-dev libavutil-dev libswscale-dev libtbb-dev libjpeg-dev libpng-dev libtiff-dev

OPENCV_VER="84" #fix at 4.10.0.84, or use rolling release: "4.x"
STARTDIR=$(pwd)
TMPDIR=$(mktemp -d)

# Build and install OpenCV from source.
echo $TMPDIR

# pyenv compatibility
cp .python-version $TMPDIR

cd "${TMPDIR}"
git clone --branch ${OPENCV_VER} --depth 1 --recurse-submodules --shallow-submodules https://github.com/opencv/opencv-python.git opencv-python-${OPENCV_VER}
cd opencv-python-${OPENCV_VER}
export ENABLE_CONTRIB=0
# export ENABLE_HEADLESS=1
# We want GStreamer support enabled.
export CMAKE_ARGS="-DWITH_GSTREAMER=ON -DWITH_FFMPEG=ON"
python -m pip wheel . --verbose -w $STARTDIR

# # Install OpenCV
# python3 -m pip install opencv_python*.whl
# cp opencv_python*.whl $STARTDIR