====== FPV Camera ======

The FPV Camera serves a video stream as the first person view (FPV) of the Robot. This makes it possible to see the position of the Robot and anything in its way.

===== Hardware =====

A 3d Printed mount for the Bosch40x40 profile was made to stick a polie on it so that the camera gets a better view. The camera is set in a case which was designed with a litte roof to prevent raindrops on the lense.

{{:projects:farmrobot:img_2648.jpg?400|}}

[picture of 40x40 clip with pole and camera case(n/a)]

The following hardware is used for capturing and broadcasting the video stream:
  * Raspberry Pi 4B (8GB) by element14
  * element14 Raspberry Pi CSI camera v.2 NoIR
  * USB-C cable
  * Heatsinks
  * Fan
  * Case
  * SD-Card

===== Software =====

The SD-Card has been flashed with an Ubuntu 20.10 arm64-raspi OS.
The Pi is configured with the following user:
  * user name: pi
  * password: farmrobot

Its connectable via ethernet or build in wifi module.

An initial update has been run:

''sudo apt update && sudo apt upgrade''

Also some config changes have been made:

''sudo nano /boot/firmware/config.txt [gpu_mem=512 ; start_x=1]''

==== Setup ====

  sudo apt install v4l-utils
  sudo apt install ffmpeg
  sudo apt install openssh-server sudo ufw allow ssh ssh pi@farmrobot
  
=== ffmpeg stream ===
Bash script ''stream.sh'':
  ffmpeg -f v4l2 -input_format h264 -video_size 852x480 -framerate 5 -i /dev/video0>
  -c:v h264 -preset veryfast -b:v 500k -maxrate 500k -bufsize 10k \
  -pix_fmt yuv420p -g 10 \
  -f flv "rtmp://ingest_server/streamkey" 


==== Optional v4l2m2m encoder on arm 64 bit OS ====

Using v4l2m2m encoder to have arm64 hardware support to efficiently encode a efficient h.265 stream which is sent via rtmp to a server which reencodes to hls to view video stream in a browser.

Building ffmpeg from source for the newest release and support for v4l_m2m hardware encoding on 64 bit arm.

''cd/home/pi/ mkdir -p ~/ffmpeg_sources ~/ffmpeg_build ~/bin''

(installing to /home/pi/bin/ to avoid conflicts with the system package folder)

According to [[https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu]] a lot of dependancies have to be installed beforehand:

  sudo apt-get update -qq && sudo apt-get -y install \
  autoconf \
  automake \
  build-essential \
  cmake \
  git-core \
  libass-dev \
  libfreetype6-dev \
  libgnutls28-dev \
  libsdl2-dev \
  libtool \
  libva-dev \
  libvdpau-dev \
  libvorbis-dev \
  libxcb1-dev \
  libxcb-shm0-dev \
  libxcb-xfixes0-dev \
  meson \
  ninja-build \
  pkg-config \
  texinfo \
  wget \
  yasm \
  zlib1g-dev \
  libunistring-dev
  
installing libaries, chosing wich are needed:
  
NASM (An assembler used by some libraries.) 
  
  cd ~/ffmpeg_sources &&
  wget https://www.nasm.us/pub/nasm/releasebuilds/2.15.05/nasm-2.15.05.tar.bz2 &&
  tar xjvf nasm-2.15.05.tar.bz2 &&
  cd nasm-2.15.05 &&
  ./autogen.sh &&
  PATH="$HOME/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" --bindir="$HOME/bin" &&
  make -j 4 &&
  make install

libx264 (H.264 video encoder, fallback) 
  
  cd ~/ffmpeg_sources &&
  git -C x264 pull 2> /dev/null || git clone --depth 1 https://code.videolan.org/videolan/x264.git &&
  cd x264 &&
  PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure --prefix="$HOME/ffmpeg_build" --bindir="$HOME/bin" --enable-static --enable-pic &&
  PATH="$HOME/bin:$PATH" make -j 4 &&
  make install

libx265 (H.265/HEVC video encoder) 

  sudo apt-get install libnuma-dev &&
  cd ~/ffmpeg_sources &&
  git -C x265_git pull 2> /dev/null || git clone https://bitbucket.org/multicoreware/x265_git &&
  cd x265_git/build/linux &&
  PATH="$HOME/bin:$PATH" cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$HOME/ffmpeg_build" -DENABLE_SHARED=off ../../source &&
  PATH="$HOME/bin:$PATH" make -j 4 &&
  make install

libvpx (VP8/VP9 video encoder/decoder, another efficient video encoder, needs testing) 
  
  cd ~/ffmpeg_sources &&
  git -C libvpx pull 2> /dev/null || git clone --depth 1 https://chromium.googlesource.com/webm/libvpx.git &&
  cd libvpx &&
  PATH="$HOME/bin:$PATH" ./configure --prefix="$HOME/ffmpeg_build" --disable-examples --disable-unit-tests --enable-vp9-highbitdepth --as=yasm &&
  PATH="$HOME/bin:$PATH" make -j 4 &&
  make install

libaom (AV1 video encoder/decoder) 

  cd ~/ffmpeg_sources &&
  git -C aom pull 2> /dev/null || git clone --depth 1 https://aomedia.googlesource.com/aom &&
  mkdir -p aom_build &&
  cd aom_build &&
  PATH="$HOME/bin:$PATH" cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$HOME/ffmpeg_build" -DENABLE_SHARED=off -DENABLE_NASM=on ../aom &&
  PATH="$HOME/bin:$PATH" make -j 4 &&
  make install

libsvtav (AV1 video encoder/decoder) 

  cd ~/ffmpeg_sources &&
  git -C SVT-AV1 pull 2> /dev/null || git clone https://gitlab.com/AOMediaCodec/SVT-AV1.git &&
  mkdir -p SVT-AV1/build &&
  cd SVT-AV1/build &&
  PATH="$HOME/bin:$PATH" cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$HOME/ffmpeg_build" -DCMAKE_BUILD_TYPE=Release -DBUILD_DEC=OFF -DBUILD_SHARED_LIBS=OFF .. &&
  PATH="$HOME/bin:$PATH" make -j 4 &&
  make install

libdav1d (AV1 decoder, much faster than the one provided by libaom Users whose distributions don't provide a recent enough version of meson (0.49.0 or newer) will need to install a more up-to-date version. This is easily done via the Python Package Index: 
''sudo apt-get install python3-pip && pip3 install --user meson''

  cd ~/ffmpeg_sources &&
  git -C dav1d pull 2> /dev/null || git clone --depth 1 https://code.videolan.org/videolan/dav1d.git &&
  mkdir -p dav1d/build &&
  cd dav1d/build &&
  meson setup -Denable_tools=false -Denable_tests=false --default-library=static .. --prefix "$HOME/ffmpeg_build" --bindir="$HOME/bin" --libdir="$HOME/ffmpeg_build/lib" &&
  ninja &&
  ninja install

Audio libaries are probably needed for building, especially libfdk_aac for vpx libfdk-aac (AAC audio encoder) 

  cd ~/ffmpeg_sources &&
  git -C fdk-aac pull 2> /dev/null || git clone --depth 1 https://github.com/mstorsjo/fdk-aac &&
  cd fdk-aac &&
  autoreconf -fiv && ./configure --prefix="$HOME/ffmpeg_build" --disable-shared &&
  make -j 4 &&
  make install

libmp3lame libopus

Building FFmpeg 

  cd ~/ffmpeg_sources &&
  wget -O ffmpeg-snapshot.tar.bz2 https://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2 &&
  tar xjvf ffmpeg-snapshot.tar.bz2 &&
  cd ffmpeg &&
  PATH="$HOME/bin:$PATH" PKG_CONFIG_PATH="$HOME/ffmpeg_build/lib/pkgconfig" ./configure
  --prefix="$HOME/ffmpeg_build"
  --pkg-config-flags="--static"
  --extra-cflags="-I$HOME/ffmpeg_build/include"
  --extra-ldflags="-L$HOME/ffmpeg_build/lib"
  --extra-libs="-lpthread -lm"
  --bindir="$HOME/bin"
  --enable-gpl
  --arch=aarch64
  --enable-gnutls
  --enable-libaom
  --enable-libsvtav1
  --enable-libdav1d
  --enable-libvpx
  --enable-libx264
  --enable-libx265
  --enable-nonfree &&
  PATH="$HOME/bin:$PATH" make -j 4 &&
  make install &&
  hash -r
  
  source ~/.profile

===== Authors =====
* Jonas Geßmann, Environment & Energy, jonas.gessmann@protonmail.com \\
* Nicolas Wiehe