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Status - Incubating GitHub Actions Workflow Status


Open1722 logo

Covesa Open1722

Open1722 is an implementation of the IEEE 1722 protocol, for streaming audio/video, tunneling CAN/LIN messages and enabling remote access to peripheral bus systems.

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Introduction

Open1722 is a fork of AVNU/libavtp which is an open source reference implementation of the Audio Video Transport Protocol (AVTP) specified in IEEE 1722-2016 spec. libavtp primarily focuses on audio video data formats of the IEEE 1722-2016 spec.

IEEE 1722 is also gaining a lot of traction in the automotive community, mainly, to bridge fieldbus technologies over automotive Ethernet. In particular the AVTP Control Formats (ACF) specify serialization for a set of data formats relevant for automotive applications (e.g., CAN, LIN, etc.). Open1722 extends/modifies libavtp to also include these ACF formats.

NOTE: Open1722 is currently incubating and under active development. The APIs are not fully stable and are subject to changes.

Open1722 is under BSD License. For more information see LICENSE file.

Implementation

This repository is organized as follows:

  • The src/ and include/ folders contain the IEEE 1722 protocol implementation. We strive to make the implementation platform independant and avoid usage of platform specific headers or libraries. For now the implementation is tested only on Linux.
  • The examples/ folder contains various applications that use our Open1722 library. The applications are targeted to Linux platforms.

Before building Open1722 make sure you have installed the following software :

  • CMake >= 3.20
  • CMocka >= 1.1.0 (For running unit tests. This can be installed on Debian/Ubuntu using sudo apt install libcmocka-dev)

Alternatively, you can use VS Code to run the provided dev container which takes care of the dependencies.

The first step to build Open1722 is to generate the Makefile and build the project.

$ mkdir build
$ cd buid
$ cmake ..
$ make

To execute available unit tests, set the Cmake variable UNIT_TESTING.

$ cmake .. -DUNIT_TESTING=on
$ make

The build can be cleaned using the following command:

$ make clean

To install Open1722 on your system run:

$ sudo make install

AVTP Formats Support

AVTP protocol defines several AVTPDU type formats (see Table 6 from IEEE 1722-2016 spec).

The following is the list of the formats currently supported by Open1722:

  • AAF (PCM encapsulation only)
  • CRF
  • CVF (H.264, MJPEG, JPEG2000)
  • RVF
  • AVTP Control Formats (ACF) with Non-Time-Synchronous as well as Time-Synchronous formats (see Table 22 from IEEE 1722-2016 spec)
    • CAN
    • CAN Brief
    • Flexray
    • LIN
    • MOST
    • GPC
    • Sensor
    • Sensor Brief
  • Custom formats not included in the standard but can be transported on top of IEEE 1722

Examples

The examples/ directory provides sample applications which demonstrate the Open1722 functionalities. Each example directory contains a README file that includes specific details on its functionality, configuration, and dependencies.

To execute the IEEE 1722 CAN Talker application:

$ ./build/acf-can-talker

Programming Tutorial

Here's a small example how the Open1722 library can be used to build and parse IEEE 1722 Protocol Data Units (aka PDUs). First define a C struct for a custom IEEE 1722 packet that can be used to transport a CAN and a LIN message. The frame begins with a Time-synchronous Control Format (TSCF) header. Alternatively a Non-Timesynchronous Control Format (NTSCF) header could be used. After the TSCF header a list of AVTP Control Format (ACF) messages follows. The first ACF message is a ACF CAN message which consists of ACF CAN header as well as a payload section to carry a 2Byte CAN frame. Similar than with the CAN message another ACF messages for LIN is added.

// my_1722_pdu.h

#include "avtp/Udp.h"
#include "avtp/acf/Tscf.h"
#include "avtp/acf/Can.h"
#include "avtp/acf/Lin.h"

#define CAN_PAYLOAD_LEN 2
#define LIN_PAYLOAD_LEN 3

typedef struct {
    // IEEE 1722 UDP encapsulation header (optional)
    Avtp_Udp_t udp;
    // IEEE 1722 TSCF header
    Avtp_Tscf_t tscf;
    // IEEE 1722 ACF message #1
    Avtp_Can_t can;
    uint8_t canPayload[CAN_PAYLOAD_LEN];
    // IEEE 1722 ACF message #2
    Avtp_Lin_t lin;
    uint8_t linPayload[LIN_PAYLOAD_LEN];
} My1722Pdu_t;

In the next step we're going to c

// talker.h

#include "my_1722_pdu.h"

int main()
{
    My1722Pdu_t pdu;

    // Init UDP encapsulation header
    Avtp_Udp_Init(&pdu.udp);

    // Init TSCF header
    Avtp_Tscf_Init(&pdu.tscf);
    Avtp_Tscf_SetVersion(&pdu.tscf, 0);
    Avtp_Tscf_SetSequenceNum(&pdu.tscf, 123);
    Avtp_Tscf_SetStreamId(&pdu.tscf, 0xAABBCCDDEEFF);
    Avtp_Tscf_SetTv(&pdu.tscf, 1);
    Avtp_Tscf_SetAvtpTimestamp(&pdu.tscf, 0x11223344);

    // Init CAN ACF message
    Avtp_Can_Init(&pdu.can);
    Avtp_Can_SetCanBusId(&pdu.can, 4);
    uint8_t canFrame[CAN_PAYLOAD_LEN] = {0x11, 0x22};
    memcpy(pdu.can.payload, canFrame, CAN_PAYLOAD_LEN);

    // Init LIN ACF message
    Avtp_Lin_Init(&pdu.lin);
    uint8_t linFrame[LIN_PAYLOAD_LEN] = {0x11, 0x22, 0x33};
    memcpy(pdu.lin.payload, linFrame, LIN_PAYLOAD_LEN);

    // Send packet to network using socket API ...
    uint8_t* data = &pdu;
    size_t dataLen = sizeof(My1722Pdu_t);
    // int socket = ...
    // sendto(socket, data, dataLen, 0);
}