VCR4J

Video controls for various devices. Used by MBARI's video annotation and reference system. The design of this library depends heavily on ReactiveX and can be summed up by:

VideoController ---> VideoIO ---> Observable<VideoError>
                             |--> Observable<VideoIndex>
                             |--> Observable<VideoState>
                             `--> Subject<VideoCommand>

The VideoIO object sends VideoCommand objects via the commandSubject. Response are parsed and the appropriate observable: errorObservable, indexObservable, or stateObservable is updated.

Any implentation of VideoCommand can be sent to a VideoIO object, but it will only respond to ones it knows about (you can modify this with decorators though).

Example usage can be found in the vcr4j-examples module.

Usage

Adding to your project

<dependencies>
    <!-- Here's an example for adding RXTX support for VCR's via RS422: -->
    <dependency>
        <groupId>org.mbari.vcr4j</groupId>
        <artifactId>vcr4j-rxtx</artifactId>
        <version>5.1.3.jre17</version>
    </dependency>
</dependencies>

Creating a VideoIO object

VideoIO implementations manage the communication between java and the video device. Simply create the VideoIO object you need for managing your video device. Typically, each VideoIO object has an open method that accepts the parameters need to connect to the video device. There are a number of decorators that you can add to modify the behavior of a VideoIO object. Here's an example:

// A basic VideoIO object opens a connection. Sends commands and parses responses. 
VideoIO<RS422State, RS422Error> rawIO = RXTXVideoIO.open(serialPortName);

// Keep UI in sync by scheduling status/time requests
new VCRSyncDecorator<>(rawIO);

// Keep UI in sync by sending status/timecode requests after certain commands
new RS422StatusDecorator(rawIO);

// Log IO trafic
new LoggingDecorator(rawIO);

// Move all IO traffic off of the current thread to some Executor that you specify. 
// Extremely important for UI apps
VideoIO<RS422State, RS422Error>  io = new SchedulerVideoIO<>(simpleIO, Executors.newCachedThreadPool());

Using a VideoIO object

You can either send command directly using the IO object or wrap it in a VideoController.

VideoIO<RS422State, RS422Error>  io =  // ... see above about creating one

// watch for video indices (e.g. timecode) and print them out
io.getIndexObservable()
    .map(vi -> new VideoIndexAsString(vi))
    .subscribe(s -> System.out.println(s))

VideoController<RS422State, RS422Error> controller = new VideoController(io);

// You can send a play command using either of these methods
io.send(VideoCommands.PLAY)
controller.play()

// You can request video index using either of these methods
io.send(VideoCommands.REQUEST_INDEX
controller.requestIndex()

// etc.

// When done with a videoIO object close it to free resources
io.close()

Notes

• When testing on Mac OS X 10.11 using a GUC232A usb-to-serial device and prolific's drivers. THe port doesn't seem to close property with RXTX. I'm force to unplug and replug it in after each test to reset the port.
• When testing on Mac OS X 10.11 using a GUC232A usb-to-serial device neither JSSC or Purejavacomm appear to work. PJC does work with the serial ports on the DeckLink cards though.