cScriptReader

A Reader that is returned by cScriptFilter::createInputPin. More...

Inheritance diagram for cScriptReader:

Signals
void	streamTypeChanged (QObject *type)
	Connect to this signal to handle new Stream Types recieved via the associated Pin. More...
void	trigger (qint64 timestamp)
	Connect to this signal to handle Data In Triggers in the associated Pin. More...
void	sample (const QVariant &sample)
	Connect to this signal to handle Samples received via the associated Pin. More...

Public Member Functions
Q_INVOKABLE QVariant	getNextSample ()
	Returns the next available sample. More...
Q_INVOKABLE QVariant	getLastSample ()
	Returns the last available sample. More...
Q_INVOKABLE void	requestSamples (const QString &strSubStream)
	Request samples from a given Substream. More...
Q_INVOKABLE void	cancelRequest (const QString &strSubStream)
	Cancels a request for samples from a given Substream. More...

Detailed Description

A Reader that is returned by cScriptFilter::createInputPin.

Samples returned by getNextSample(), getLastSample() and passed via the sample() signal contain the following elements:

• sample.timestamp: contains the timestamp of the sample in nanoseconds.
• sample.substream: contains the name of the substream that the sample belongs to (can be empty)
• sample.data: contains the payload of the sample in one of the following forms:
  • For streams that have a media description:
    • A javascript object that represents the data structure of the media description, i.e sample.data.parent.child.value etc.
  • For streams with stream type "adtf/image" (adtf::streaming::ant::stream_meta_type_image)
    • A QImage with the image data.
  • For all others
    • A javascript ArrayBuffer object containing the raw data bytes of the sample

Please keep in mind that when you do not connect a callback to both trigger() and sample(), all incoming samples will be discarded.

Definition at line 127 of file builds/digitalwerk/solutions/adtf_content/adtf_base/adtf_core/src/libraries/javascriptfiltersdk/src/reader.h.

Member Function Documentation

cancelRequest()

Q_INVOKABLE void cancelRequest

(

const QString &

strSubStream

)

Cancels a request for samples from a given Substream.

Parameters

[in]

strSubStream

The substream.

getLastSample()

Q_INVOKABLE QVariant getLastSample

(

)

Returns the last available sample.

Example Usage

var input = filter.createInputPin("input")
input.trigger.connect(function(timestamp)
{
    console.info("last sample: " + JSON.stringify(input.getLastSample()))
})

Warning

Mind that this does not work for Substreams.

Returns

The last sample available or false.

getNextSample()

Q_INVOKABLE QVariant getNextSample

(

)

Returns the next available sample.

Example Usage

var input = filter.createInputPin("input")
input.trigger.connect(function(timestamp)
{
    var sampleCount = 0
    while ((sample = input.getNextSample()))
    {
        ++sampleCount
    }
 
    console.info("recieved " + sampleCount + " samples")
})

Returns

The next sample available or false.

requestSamples()

Q_INVOKABLE void requestSamples

(

const QString &

strSubStream

)

Request samples from a given Substream.

Example Usage

var input = filter.createInputPin("input")
 
input.requestSamples("stream1")
input.requestSamples("stream2")
 
input.sample.connect(function(sample)
{
    if (sample.substream === "stream1")
    {
        console.info("recieved sample from substream stream1")
    }
    else if (sample.substream === "stream2")
    {
        console.info("recieved sample from substream stream2")
    }
})

Parameters

[in]

strSubStream

The Substream.

sample

void sample ( const QVariant &  sample )

signal

Connect to this signal to handle Samples received via the associated Pin.

Note this signal is only emitted if the trigger() signal has no receivers.

Example Usage

var input = filter.createInputPin("input")
input.sample.connect(function(sample)
{
    console.info("sample with timestamp " + sample.timestamp)
})

Parameters

sample

The sample.

streamTypeChanged

void streamTypeChanged ( QObject *  type )

signal

Connect to this signal to handle new Stream Types recieved via the associated Pin.

Example Usage

var input = filter.createInputPin("input")
input.streamTypeChanged.connect(function(type)
{
    console.info("stream type: " +  JSON.stringify(type))
})

Parameters

type	The stream type (see adtf::javascript::scripting::cStreamTypeWrapper)

trigger

void trigger ( qint64  timestamp )

signal

Connect to this signal to handle Data In Triggers in the associated Pin.

Example Usage

var input = filter.createInputPin("input")
input.trigger.connect(function(timestamp)
{
    console.info("trigger at " + timestamp)
})

Process Samples from multiple inputs on a single trigger

Parameters

timestamp

The timestamp of the trigger in nanoseconds.