This is C++ implementation of Carplay receiver and Android Auto receiver for "Autobox" dongles. The purpose of the project is to make application lightweight to run on Raspberry PI Zero 2W using hardware decoding.
The dongles are readily available from Amazon or Aliexpress labeled by Carlinkit or CPC200-CCPM. They also seems to have official web site https://www.carlinkit.com/. Devices might have different vendor and product id's. Check your with lsusb and update settings if necessary.
Important
For detailed guide on set Raspberry Pi Zero 2W visit Raspbery Pi Setup WIKI page
The project is based on SDL2, FFMPEG, LIBUSB. It use XXD for resource embedding.
sudo apt install build-essential xxd libsdl2-dev libsdl2-ttf-dev libavformat-dev libavcodec-dev libavutil-dev libswscale-dev libusb-1.0-0-dev libssl-dev
To run the application you also need to install runtime
sudo apt install ffmpeg libsdl2-2.0-0 libsdl2-ttf-2.0-0 libusb-1.0-0 libssl3
On linux app may not have permissions to read USB device. You need to create udev rule to grant permissions for dongle. First you need to figure out your idVendor and idProduct.
lsusb
You will see list of devices, try to find the one that looks like dongle. Also you might need to run lsusb several time, cause my dongle seems to be disconnecting all the time. You need to find line like
Bus 003 Device 066: ID 1314:1520 Magic Communication Tec. Auto Box
So in my case ID 1314:1520 shows idVendor 1314 and idProduct 1520. We need to use those to create udev rules. If yours are different you also need to put them in settings.txt and run application with settings.txt as argument. Remember that in settings.txt values are in decimal, so you need to convert hex values to base 10 first. Create udev rules and add user to plugdev group, replace <Vendor> <Product> and <Your user name> with your informations
echo 'SUBSYSTEMS=="usb", ATTRS{idVendor}=="<Vendor>", ATTRS{idProduct}=="<Product>", GROUP="plugdev", MODE="0660"' | sudo tee /etc/udev/rules.d/50-carlinkit.rules
## example: SUBSYSTEM=="usb", ATTRS{idVendor}=="1314", ATTRS{idProduct}=="1520", GROUP="plugdev", MODE="0660"
sudo usermod -aG plugdev <Your user name>
## example: sudo usermod -aG plugdev linux
sudo udevadm control --reload-rules
sudo udevadm trigger
The application can be started with settings file. Sample of the settings file can be found in settings.txt. Make sure that you put proper device id in settings and app have access to usb (see previous step) The project is using make. You can edit ./conf/settings.txt after copy if needed. From the repository root run following
make clean
make release
mkdir ./conf
cp ./settings.txt ./conf
./out/app ./conf/settings.txt
You can change font and background images by replacing files in ./src/resource
- background.bmp for background image. Use BMP format only.
- font.ttf for font. Use TTF format only
- you can edit colours.h to modify text colours in RGBA format
The names of the file need to be exactly same. Resources are embedded in executable, remake the project to regenerate resources
make clean
make release
The following keys have been mapped:
- Left - navigate left
- Right - navigate right
- Enter - select active item
- Backspace - Go back
- f - toggle fullscreen mode
- q - exit
- r - force refresh
What is working:
- Carplay and Android Auto
- Video
- Audio (multiple channels)
- Key navigation
- Simple touch
- Microphone (calls, siri)
What is not working:
- Multi touch - i have no means to test it and no idea how it should work
- Some android keys are not mapped
- No methods to edit autoconnect list or switch wireless devices
- Do not try to run debug builds if you do not need to debug application. They consume a lot of memory for address sanitising thats grow over time.
- Increasing FPS above Source-FPS will cause app to run UI loop with less delays and do more event polling. This can increase responsivenes of the system, but also will make X11 to use more resources.
- For multichannel audion (driving guidance over music) you need to have multichannel driver in the system (puslsaudio, pipewire). If you only have ALSA backend the second channel will not work
- Android has it's own video resolution system which is fixed for 480p 720p 1080p. So set up resolution that is closest to what you want and adjust DPI for UI scale. If you do not have full screen Android Auto, you might need to enable resolution negotiation. Go to Android Auto app info and search for "Additional settings in the app" option. Scrol down and tap fast 5 times on version. Now you can use top right three dots menu to go to "Developer settings". Tap "Video Resolution" and select "Allow to car and phone to negotiate".
Done
- Implement direct buffer transfer from video decoder to renderer (should reduce amount of memory copies and CPU load)
- Control audio buffers better (now system use 3 decoding threads but in reality only 2 required)
- Reduce music volume when there is navigation messages
- Add abilities to run script on device connect and device disconnect
- Add encrypted USB communication option with magic code 0x55bb55bb for new firmware
- Improve touch responsiveness
- Protocol debugging option + python script to decode usb dumps
- Android Auto (have not tested much, but seems to work for me)
- Microphone support (Calls, Siri)
Next
- Car menu with status, settings and options to run custom scripts
- Canbus script communication or some sort of side key press handling
- Better android navigation
- Switch between wireless devices
The project is inspired and based on great work done by other developers:
- pycarplay by electric-monk
- carplay-receiver by harrylepotter
- react-carplay by rhysmorgan134
- carplay-client by rayphee
The project is licenced under GPL-3 licence. See LICENCE for details. The project is using Open Sans font. See FONT_LICENCE for details.
If you have any questions, suggestions or you find problems running this feel free to open issue.