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avdecc-lib

Simple C++ library for implementing IEEE1722.1 (AVB Device Enumeration, Discovery and Control).

Introduction

This library aims to simplify development of an AVDECC Controller based on the IEEE1722.1 specification. It provides a simple C++ object interface to 1722.1 objects and implements device discovery and enumeration as a background process.

The repository contains source to build a Windows DLL or a Linux library and a command line application for exercising the library.

The overall philosophy of AVDECC LIB is to implement a thin layer of commands that allow an application to discover and control AVDECC capable End Stations. The internal operations of the library are designed to be single threaded, although multiple threads are used to queue operations to be performed by the single threaded "engine" portion of the library. The library supports notification events (callbacks) that are triggered on the success (or failure) of a command. It is up to the application to process the notifications in a useful manner. Asynchronous descriptor updates from an End Station are also supported. A descriptor notification does not have data about the updated descriptor values embedded in it. Instead the AVDECC application should query the descriptor class to obtain the updated values.

Operations that "fetch" details or status of an End Station store the response for later readback by the controller application. An example of this would be the AEM send_get_stream_info_cmd() operation whose response is stored in the appropriate stream input object in avdecc-lib. Functions get_stream_info_msrp_accumulated_latency(), get_stream_info_msrp_failure_code() and others can then be used to readback fields of the response.

Users developing 1722.1 end stations and controllers are encouraged to add new descriptors to this library as required. The library provides an easy entry point for adding and testing a completely new 1722.1 descriptor without having to develop a complete controller side 1722.1 software stack.

Dependencies

Uses Jeff Koftinoff's packet processing library, see https://github.com/jdkoftinoff/jdksavdecc-c.git This is a submodule that can be cloned using:

cd avdecc-lib
git submodule init
git submodule update

As of March 2014, avdecc-lib is following the master branch of jdksavdecc-c (from github).

Acknowledgements

Special thanks are owed to Jeff Koftinoff for creating and releasing public source for 1722.1 packet processing in the jdksavdecc-c library and for comments and advice freely given during the development of this library. This C++ library is a rather thin wrapper around functions already present in the jdksavdecc-c library.

Community

Please join Google Group "avdecc-lib" if you wish to comment on avdecc-lib, or keep track of discussions.

Directory layout

controller\	
	lib\
		bin\
		doc\
		binding\
			python\
		include\ (contains public header files)
		src\ (contains private header files and C++ source code)
			linux\ (linux specific files)
			msvc\ (Microsoft Visual Studio specific files)
			
	app\
		bin\
		doc\
		cmdline\
			src\
		test\
			strings\
			adp\
			logging\ 
			notify\		

Object hierarchy

System
Controller
	End Station[1..N]
		Entity[1..N]
			Configuration[1..N]
				Audio Unit[1..N]
						Stream Port Input[0..N]
									Audio Cluster[0..N]
									Audio Map[0..N]
									Control[0..N]
						Stream Port Output[0..N]
									Audio Cluster[0..N]
									Audio Map[0..N]
									Control[0..N]
						External Port Input[0..N]
						External Port Output[0..N]
						Internal Port Input[0..N]
						Internal Port Output[0..N]
						Control[0..N]
						Signal Selector[0..N]
						Mixer[0..N]
						Matrices[0..N]
						Splitter[0..N]
						Combiner[0..N]
						Demultiplexer[0..N]
						Transcoder[0..N]
						Control Block[0..N]
				Stream Input[1..N]
				Stream Output[1..N]
				Jack Input[1..N]
				Jack Output[1..N]
				AVB Interface[1..N]
				Clock Source[1..N]
				Clock Domain[1..N]

Building

All build environments require

1. cmake v2.8

Run cmake to create the build dirctories for your environment.

cd avdecc-lib
cmake .

Windows

Prerequisites

1. MSVC 2013 or later
2. winpcap development package from http://www.winpcap.org/devel.htm

The following environment variables must be defined:

• WPCAP_DIR the directory where WinPcap is installed

Get the lib from github:

• Make and enter the project directory
• git clone git://github.com/audioscience/avdecc-lib
• cd avdecc-lib
• git submodule init
• Edit in .git/config, change url = [email protected]:jdkoftinoff/jdksavdecc-c.git to url = git ://github.com/jdkoftinoff/jdksavdecc-c.git
• git submodule update

Compile

• Open command window to "project folder" AVDECC-Lib
• Initialize compiler environment : "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\vcvarsall.bat" x86
• cmake .
• msbuild ALL_BUILD.vcxproj
• cd controller
• cmake .
• msbuild ALL_BUILD.vcxproj

Run

• controller.dll located in : AVDECC-Lib\avdecc-lib\controller\lib\Debug
• command line app located in : AVDECC-Lib\avdecc-lib\controller\app\cmdline\Debug
• Copy controller.dll to app folder
• Run application

Linux

Prerequisites

1. gcc development environment (v4.8 or later)
2. libedit
3. readline library, may need to go "sudo apt-get install libreadline5-dev" or "sudo apt-get install libreadline-gplv2-dev"

OSX

Prerequisites: cmake installed (http://www.cmake.org/):

Get the lib from github:

• Make and enter the project directory
• git clone git://github.com/audioscience/avdecc-lib --recursive

Compile

• cd avdecc-lib

• cmake .

• NOTE: the Readline library used by avdecccmdline can be specified via cmake.

• NetBSD Editline (libedit) is the default, but the GNU Readline Library can be referenced by passing in

• the argument: -DUSE_GNU_READLINE=ON

• make

Operations

AVDECC Controller version

The AVDECC Controller version number can be updated inside the version header file.

AVDECC End Station Discovery

When the AVDECC system receives an AVDECC advertise message from an End Station, it proceeds to enumerate the End Station's complete object model, if it has not done so already. Upon completion of the enumeration process, a notification message is sent to the application.

AVDECC AEM descriptor reads

A descriptor read by referencing the object the object of interest. Since the AVDECC system has already read all descriptors, the read operation is completed without producing any network traffic.

To read the name of the first input jack, one would go:

controller->end_station(0)->entity(0)->configuration(0)->input_stream(0)->get_name(name)

Release 0.6 update:

To avoid the possible issue of an asynchronous response thread updating a descriptor value while it is being read in the cmdline, a new AEM descriptor read process has been implemented. All the methods required to read each descriptor are separated into response classes, which read the descriptor values from a stored response frame.

To read the current sampling rate from an audio unit descriptor:

avdecc_lib::audio_unit_descriptor_response *audio_unit_resp_ref = audio_unit_desc_ref->get_audio_unit_response();
audio_unit_resp_ref->current_sampling_rate();
delete audio_unit_resp_ref;

AVDECC AEM commands

An AVDECC command is sent to the target object, ie:

istream = controller->end_station(0)->entity(0)->configuration(0)->input_stream(0);
id = (void *)notify_id;
// put the notify_id value in a list somewhere
istream->set_format(id, format,...);
notify_id++;

Completion results in a notification message of success or failure via the callback mechanism. An alternative calling sequence is to wait for the callback to complete in-line, ie:

id = (void *)notify_id;
avdecc_system->set_wait_for_next_cmd(id);
istream = controller->end_station(0)->entity(0)->configuration(0)->input_stream(0);
istream->set_format(id, format,...);
status = avdecc_system->get_last_resp_status();
notify_id++;

The above examples place an uint32_t notify_id in a "void *" container. If the application writer is careful about object creation and destruction, they may choose to place a C++ (or other language) object in the notify_id field.

Release 0.6 update:

Similar to descriptors, AVDECC command response processing has been altered to account for the possibility of an asynchronous response writing to a memory location while it is being read in the cmdline. So far, GET_ commands that return a value (e.g. get_counters) have been updated to return their response in a response class.

To read the locked counter from clock domain counters:

avdecc_lib::clock_domain_counters_response *clock_domain_counters_resp = clock_domain_desc_ref->get_clock_domain_counters_response();
if(clock_domain_counters_resp->get_counter_valid(avdecc_lib::CLOCK_DOMAIN_LOCKED))
    atomic_cout << "Locked Counter: " << clock_domain_counters_resp->get_counter_by_name(avdecc_lib::CLOCK_DOMAIN_LOCKED) << std::endl;
delete clock_domain_counters_resp;

Callbacks

The following callback functions should be supplied. If NULL is passed in for the callback function, no callback will be invoked.

void log_callback(void *log_user_obj, int32_t log_level, const char *log_msg, int32_t time_stamp_ms);
void notification_callback(void *notification_user_obj, int32_t notification_type, uint64_t guid, uint16_t cmd_type, uint16_t desc_type, uint16_t desc_index, void *notification_id);

When a controller internal thread calls the log_callback function that was invoked at controller create time, the log_user_obj pointer that was passed in at that time is returned in the callback. The calling application code use this void pointer to store a C++ class if that was helpful to the structure of the calling application. The log_callback is called with log_level values of:

• ERROR
• WARNING
• NOTICE
• INFO
• DEBUG
• VERBOSE

Like the log_callback function the notification callback returns a void "user" pointers as the first field in the callback. The notification_callback is called with notification_type values of:

• NO MATCH FOUND
• END STATION CONNECTED
• END STATION DISCONNECTED,
• COMMAND TIMEOUT
• RESPONSE RECEIVED
• END_STATION_READ_COMPLETED

Source code style

Source code is auto-formatted using the astyle formatting tool. All submitted pull requests should be passed through astyle before the pull request is issued. The format to use is specified in the astyle_code_format option file in this directory. asytle is run from the command line using the following command sequence:

AStyle --options=..\avdecc-lib\astyle_code_style.txt ..\avdecc-lib\controller\lib\include\*.h
		 ..\avdecc-lib\controller\lib\src\*.h ..\avdecc-lib\controller\lib\src\*.cpp
		 ..\avdecc-lib\controller\lib\src\msvc\*.h ..\avdecc-lib\controller\lib\src\msvc\*.cpp

Source documentation

A standard tool, Doxygen, is used for generating documentation from the AVDECC Controller Lib source code. A link to the online version of the AVDECC Controller Lib documentation can be found at: http://www.audioscience.com/internet/download/sdk/avdecclib_usermanual_html/html/index.html

Development Conventions

Developers should add new features to the staging git branch. Periodically the staging git branch will be merged to the master branch.

Roadmap

Working towards release version 1.0.0.

Release 1.0.0 supports:

• all of the P1 Command/responses listed below.
• Windows, linux and OSX builds.

Future features include:

• security key passing
• Layer 3 (IP) interface
• other descriptors as required

Status

Command/Response	Priority	Implemented	Tested
ACQUIRE_ENTITY	P1	Y	Y
LOCK_ENTITY	P1	Y	Y
ENTITY_AVAILABLE	P1	Y	Y
CONTROLLER_AVAILABLE	P1	Y	Y
READ_DESCRIPTOR	P1	Y	Y
SET_STREAM_FORMAT	P1	Y	Y
GET_STREAM_FORMAT	P1	Y	Y
SET_STREAM_INFO	P1
GET_STREAM_INFO	P1	Y	Y
SET_SAMPLING_RATE	P1	Y	Y
GET_SAMPLING_RATE	P1	Y	Y
SET_CLOCK_SOURCE	P1	Y	Y
GET_CLOCK_SOURCE	P1	Y	Y
START_STREAMING	P1	Y	Y
STOP_STREAMING	P1	Y	Y
SET_CONFIGURATION	P2
GET_CONFIGURATION	P2
SET_CONTROL	P2
GET_CONTROL	P2
SET_NAME	P2	Y	Y
GET_NAME	P2	Y	Y
SET_MIXER	P2
GET_MIXER	P2
REGISTER_UNSOLICITED_NOTIFICATION	P2	Y	Y
DEREGISTER_UNSOLICITED_NOTIFICATION	P2	Y	Y
IDENTIFY_NOTIFICATION	P2
GET_AVB_INFO	P2
GET_AS_PATH	P2
REBOOT	P2
WRITE_DESCRIPTOR	P3
SET_ASSOCIATION_ID	P3
GET_ASSOCIATION_ID	P3
INCREMENT_CONTROL	P3
DECREMENT_CONTROL	P3
SET_SIGNAL_SELECTOR	P3
GET_SIGNAL_SELECTOR	P3
SET_MATRIX	P3
GET_MATRIX	P3
GET_COUNTERS	P3	Y	Y
GET_AUDIO_MAP	P3	Y	Y
ADD_AUDIO_MAPPINGS	P3	Y	Y
REMOVE_AUDIO_MAPPINGS	P3	Y	Y
START_OPERATION	P3
ABORT_OPERATION	P3
OPERATION_STATUS	P3
SET_VIDEO_FORMAT	P4
GET_VIDEO_FORMAT	P4
SET_SENSOR_FORMAT	P4
GET_SENSOR_FORMAT	P4
GET_VIDEO_MAP	P4
ADD_VIDEO_MAPPINGS	P4
REMOVE_VIDEO_MAPPINGS	P4
GET_SENSOR_MAP	P4
ADD_SENSOR_MAPPINGS	P4
REMOVE_SENSOR_MAPPINGS	P4

ToDo

Release Notes

None so far.