Lazycast: A Simple Wireless Display Receiver

Description

lazycast is a simple wifi display receiver. It was originally targeted Raspberry Pi (as display) and Windows 8.1/10 or Android (as source) , but it might work with other Linux distros and Miracast sources, too. In general, lazycast does not require re-compilation of wpa_supplicant to provide p2p capability, and should work on an "out of the box" Raspberry Pi.

It is also highly recommended use a external dongle, raspberry 3 use a common wifi/bluetooth BCM43438 and this cause issues when the bluetooth is enable

Preparation

Working with wpa_supplicant v2.8-devel and dhcpcd 8.1.2 For raspbian Buster

UPGRADE YOUR PI3

sudo apt-get update
sudo apt-get upgrade

Install

sudo -i
bash <(curl -s https://raw.githubusercontent.com/amerinoj/lazycast/master/install-lazycast.sh)   

Complete the menus into the install script to customize the install.

install-lazycast.sh do all config but if you want customized the install more. continue reading:

INSTALL MANUALLY

DEFINE THE INTERFACE

• Modify the /etc/dhcpcd.conf file to include "wpa_supplicant" line in the wifi adapter to work with WPA_SUPPLICANT and exclude others with line "nohook wpa_supplicant" **

• In /etc/dhcpcd.conf you can specified the ip address to other adapters

• For example to use a external dongle wlan1 for P2P wifi direct and wlan0 managemed by HOSTAP:

• if use a external dogle wlan1 add: nano /etc/dhcpcd.conf

interface wlan0
	static ip_address=192.168.42.1/24
	static routers=192.168.42.1
	static domain_name_servers=8.8.8.8 8.8.4.4
	nohook wpa_supplicant

interface wlan1
        wpa_supplicant

• if use internal wifi add: nano /etc/dhcpcd.conf

interface wlan0
	wpa_supplicant
		

More details:https://manpages.debian.org/buster/dhcpcd5/dhcpcd.conf.5.en.html

CONFIG WPA_SUPPLICANT

• Add this config to /etc/wpa_supplicant/wpa_supplicant.conf
• You can change the country=<Your_contry_code>, the contry code sould be same as the country define in raspi-conf nano /etc/wpa_supplicant/wpa_supplicant.conf

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
p2p_go_ht40=1
country=ES

CHECK OTHER DHCP SERVICES

• Lazycast has ower dhcp server integrated, make sure no other DHCP server is running in the system as dnsmasq if you are using another dhcp server for other projects, make sure is not in use under the interface selected to lazycast, use "bind config" to separate the dhcp listening interfaces.
• For example in dnsmasq.conf you can use "bind-dynamic" parameter to exclude anyinterface as eth0 and wlan1 and only use dnsmasq in one interface. nano /etc/dnsmasq.conf

bind-dynamic
no-dhcp-interface=eth0
no-dhcp-interface=wlan1
interface=wlan0
dhcp-range=interface:wlan0,192.168.42.10,192.168.42.50,255.255.255.0,24h

INSTALL DEPENDENCIES

sudo apt install libx11-dev libasound2-dev libavformat-dev libavcodec-dev

Compile libraries on Pi:

cd /opt/vc/src/hello_pi/libs/ilclient/
make
cd /opt/vc/src/hello_pi/hello_video
make

Clone this repo (to a desired directory):

cd ~/
git clone https://github.com/homeworkc/lazycast

Go to the lazycast directory then make:

cd lazycast
make

Then reboot.

Customize

Change the pin code and ip address, modify all.sh and change the pin code. You can change the ip address for p2p connection or leave it as it is .

# define options
pin="31415926"
ip_neighbor="192.168.173.2"
ip_interface="192.168.173.1"
mask="255.255.255.252"

Usage

Add execute privilege sudo chmod +x all.sh Run sudo ./all.sh` to initiate lazycast receiver. Wait until the "The display is ready" message. The name of your device will also be displayed on the pi and the wifi adapter used. Then, search for the wireless display on the source device you want to cast. The default PIN number is 31415926.
If backchannel control is supported by the source, keyboard and mouse input on Pi are redirected to the source as remote controls.
It is recommended to initiate the termination of the receiver on the source side. These user controls are often near the pairing controls on the source device. You can utilize the backchannel feature to remotely control the source device in order to close lazycast.

Tips

Set the resolution on the source side. lazycast advertises all possible resolutions regardless of the current rendering resolution. Therefore, you may want to change the resolution (on the source) to match the actual resolution of the display connecting to Pi.
Modify parameters in the "settings" section in d2.py to change the sound output port (hdmi/3.5mm) and preferred player.
The maximum resolutions supported are 1920x1080p60 and 1920x1200p30. The GPU on Pi may struggle to handle 1920x1080p60, which results in high latency. In this case, reduce the FPS to 1920x1080p50.
To change the default PIN number, replace the string 31415926 in all.sh to another 8-digit number.
To eneble debuging output change level_name='info' to level_name='debug'in all.sh also you can define the file save the output After Pi connects to the source, it has an IP address of 192.168.173.1 and this connection can be reused for other purposes like SSH. On the other hand, since they are under the same subnet, precautions should be taken to prevent unauthorized access to Pi by anyone who knows the PIN number.
Two in-house players are written for Raspberry Pi 3. Omxplayer or vlc can be used instead on other platforms.

Known issues

lazycast tries to remember the pairing credentials so that entering the PIN is only needed once for each device. However, this feature does not seem to work properly all the time with recent Raspbian images. (Using the latest Raspbian is still recommended from the security perspective. However, recent Raspbians randomize the MAC address of the p2p-dev-wlan0 interface upon reboot, while old Raspbians (example) do not. Any insights or suggestions on this issue are appreciated, and could make this important feature work again.) Therefore, re-pairing may be needed after every Raspberry Pi reboot. Try clearing the 'lazycast' information on the source device before re-pairing if you run into pairing problems.
Latency: Limited by the implementation of the rtp player used. (In VLC, latency can be reduced from 1200 to 300ms by lowering the network cache value.)
The on-board WiFi chip on Pi 3 only supports 2.4GHz. Therefore, devices/protocols that use 5.8GHz for P2P communication (e.g. early generations of WiDi) are not ("out of the box") supported.
Due to the overcrowded nature of the wifi spectrum and the use of unreliable rtp transmission, you may experience some video glitching/audio stuttering. The in-house players employ several mechanisms to conceal transmission error, but it may still be noticeable in challenging wireless environments. Interference from other devices may cause disconnections.
Devices may not fully support backchannel control and some keystrokes/clicks will behave differently in this case. The left Windows key is not captured and when it is pressed, it makes the current window to be out-of-focus and thus disables the backchannel controls. If it is pressed again the window will be in-focus.
HDCP(content protection): Neither the key nor the hardware is available on Pi and therefore is not supported.
In some phone the wifi chipset is share with bluetooth, if you experiment lag disable the bluetooth in your phone after the P2P connection will be created.

Start on boot

Method 1:

Append this line to /etc/xdg/lxsession/LXDE-pi/autostart:

@lxterminal -l --working-directory=<absolute path of lazycast> -e ./all.sh

For example, if lazycast is placed under ~/ (which corresponds to /home/pi/), append the following line to the file:

@lxterminal -l --working-directory=/home/pi/lazycast -e ./all.sh

Method 2: SystemD

You can run lazycast when booting your Pi using the systemd unit. To install, log into your Pi and run:

git clone https://github.com/homeworkc/lazycast.git
sudo -sE
cp lazycast/lazycast.service /etc/systemd/system/
systemctl daemon-reload
systemctl  enable lazycast.service
systemctl  start lazycast.service

Others

Some parts of the video player1 are modified from the codes on https://github.com/Apress/raspberry-pi-gpu-audio-video-prog. Many thanks to the author of "Raspberry Pi GPU Audio Video Programming" and, by extension, authors of omxplayer.
Using any part of the codes in this project in commercial products is prohibited. The dhcp server was based on the proyect https://github.com/pypxe/PyPXE

Fixes

This version fix the next issues

all.sh:

• Now detect external wireless cards that are manager by wpa_supplicant. using a external dongle and card is put in p2p mode the interface name is not change it, but we can use "iw dev type" to identify the mode.

D2.py:

• Add overload parameters :

  interface ip address interface mask interface name neighbor peer address

use ( d2.py -i <self_ip_address> -m -d -p <ip_peer_address>)

This fix some problems, sometimes the connection tried to establish through another network card, now when the sock is created the interface name is passed to ensure the connection is open in the correct interface

• Timeouts and payloads has been modified in the socket objects The sockets has been modify to delimit the timeout and the payload size these changes permit optimizer the load and quality in the connection. Also when you press Ctr+^C or the System send a signal the proccess exit in correct order.

• Integrated DHCP server. Now is not need use a external DHCP to assign Ip address to a peer neighbor. The code has a dhcp server integrated "dhcpserver.py" this is a partial modified code of "PyPXE" proyect. https://github.com/pypxe/PyPXE The original code was modified to assignen P2P addres "/30" and asing always the same address to diferents neigbors. This permit a exact control of address assigned and permit renew the dhcp leased time.

The dhcpserver.py is controller by threading in main program.

• Exceptions control: Now the code has a complete exceptions control code and is finished right if a exception is detected. All sockets and proccess will be closed in corect order.

-Debug level_name='info' Implemented python logging library . Now you can define the information level to debug the code, or put the level "info" to normal use.

-lazycast.service The lazycast service restart the application when detect a exit code. Restart=always RestartSec=2s lazycast.service was modified to intergrate the daemon in the main systemctl.

h264.c :

-Was suppressed the message "sound error " when only video is transmitter.