Class AppSrc

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.gobject.TypeInstance
org.gnome.gobject.GObject
org.gnome.gobject.InitiallyUnowned
org.freedesktop.gstreamer.gst.GstObject
org.freedesktop.gstreamer.gst.Element
org.freedesktop.gstreamer.base.BaseSrc
org.freedesktop.gstreamer.app.AppSrc
All Implemented Interfaces:
URIHandler, Proxy
@Generated("org.javagi.JavaGI") public class AppSrc extends BaseSrc implements URIHandler

The appsrc element can be used by applications to insert data into a GStreamer pipeline. Unlike most GStreamer elements, appsrc provides external API functions.

appsrc can be used by linking with the libgstapp library to access the methods directly or by using the appsrc action signals.

Before operating appsrc, the caps property must be set to fixed caps describing the format of the data that will be pushed with appsrc. An exception to this is when pushing buffers with unknown caps, in which case no caps should be set. This is typically true of file-like sources that push raw byte buffers. If you don't want to explicitly set the caps, you can use gst_app_src_push_sample. This method gets the caps associated with the sample and sets them on the appsrc replacing any previously set caps (if different from sample's caps).

The main way of handing data to the appsrc element is by calling the gst_app_src_push_buffer() method or by emitting the push-buffer action signal. This will put the buffer onto a queue from which appsrc will read from in its streaming thread. It is important to note that data transport will not happen from the thread that performed the push-buffer call.

The "max-bytes", "max-buffers" and "max-time" properties control how much data can be queued in appsrc before appsrc considers the queue full. A filled internal queue will always signal the "enough-data" signal, which signals the application that it should stop pushing data into appsrc. The "block" property will cause appsrc to block the push-buffer method until free data becomes available again.

When the internal queue is running out of data, the "need-data" signal is emitted, which signals the application that it should start pushing more data into appsrc.

In addition to the "need-data" and "enough-data" signals, appsrc can emit the "seek-data" signal when the "stream-mode" property is set to "seekable" or "random-access". The signal argument will contain the new desired position in the stream expressed in the unit set with the "format" property. After receiving the seek-data signal, the application should push-buffers from the new position.

These signals allow the application to operate the appsrc in two different ways:

The push mode, in which the application repeatedly calls the push-buffer/push-sample method with a new buffer/sample. Optionally, the queue size in the appsrc can be controlled with the enough-data and need-data signals by respectively stopping/starting the push-buffer/push-sample calls. This is a typical mode of operation for the stream-type "stream" and "seekable". Use this mode when implementing various network protocols or hardware devices.

The pull mode, in which the need-data signal triggers the next push-buffer call. This mode is typically used in the "random-access" stream-type. Use this mode for file access or other randomly accessible sources. In this mode, a buffer of exactly the amount of bytes given by the need-data signal should be pushed into appsrc.

In all modes, the size property on appsrc should contain the total stream size in bytes. Setting this property is mandatory in the random-access mode. For the stream and seekable modes, setting this property is optional but recommended.

When the application has finished pushing data into appsrc, it should call gst_app_src_end_of_stream() or emit the end-of-stream action signal. After this call, no more buffers can be pushed into appsrc until a flushing seek occurs or the state of the appsrc has gone through READY.

  • Constructor Details

    • AppSrc

      public AppSrc(MemorySegment address)
      Create a AppSrc instance for the provided memory address.
      Parameters:
      address - the memory address of the native object

    • AppSrc

      public AppSrc()
      Create a new AppSrc.

  • Method Details

    • getType

      public static @Nullable Type getType()
      Get the GType of the AppSrc class.
      Returns:
      the GType

    • getMemoryLayout

      public static MemoryLayout getMemoryLayout()
      The memory layout of the native struct.
      Returns:
      the memory layout

    • asParent

      protected AppSrc asParent()
      Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.
      Overrides:
      asParent in class BaseSrc
      Returns:
      the instance as if it were its parent type

    • endOfStream

      public FlowReturn endOfStream()
      Indicates to the appsrc element that the last buffer queued in the element is the last buffer of the stream.
      Returns:
      GST_FLOW_OK when the EOS was successfully queued. GST_FLOW_FLUSHING when this AppSrc is not PAUSED or PLAYING.

    • getCaps

      public @Nullable Caps getCaps()
      Get the configured caps on appsrc.
      Returns:
      the GstCaps produced by the source. gst_caps_unref() after usage.

    • getCurrentLevelBuffers

      public long getCurrentLevelBuffers()
      Get the number of currently queued buffers inside appsrc.
      Returns:
      The number of currently queued buffers.
      Since:
      1.20

    • getCurrentLevelBytes

      public long getCurrentLevelBytes()
      Get the number of currently queued bytes inside appsrc.
      Returns:
      The number of currently queued bytes.
      Since:
      1.2

    • getCurrentLevelTime

      public ClockTime getCurrentLevelTime()
      Get the amount of currently queued time inside appsrc.
      Returns:
      The amount of currently queued time.
      Since:
      1.20

    • getDuration

      public ClockTime getDuration()
      Get the duration of the stream in nanoseconds. A value of GST_CLOCK_TIME_NONE means that the duration is not known.
      Returns:
      the duration of the stream previously set with gst_app_src_set_duration();
      Since:
      1.10

    • getEmitSignals

      public boolean getEmitSignals()
      Check if appsrc will emit the "new-preroll" and "new-buffer" signals.
      Returns:
      true if this AppSrc is emitting the "new-preroll" and "new-buffer" signals.

    • getLatency

      public void getLatency(Out<Long> min, Out<Long> max)
      Retrieve the min and max latencies in min and max respectively.
      Parameters:
      min - the min latency
      max - the max latency

    • getLeakyType

      public AppLeakyType getLeakyType()
      Returns the currently set GstAppLeakyType. See gst_app_src_set_leaky_type() for more details.
      Returns:
      The currently set GstAppLeakyType.
      Since:
      1.20

    • getMaxBuffers

      public long getMaxBuffers()
      Get the maximum amount of buffers that can be queued in appsrc.
      Returns:
      The maximum amount of buffers that can be queued.
      Since:
      1.20

    • getMaxBytes

      public long getMaxBytes()
      Get the maximum amount of bytes that can be queued in appsrc.
      Returns:
      The maximum amount of bytes that can be queued.

    • getMaxTime

      public ClockTime getMaxTime()
      Get the maximum amount of time that can be queued in appsrc.
      Returns:
      The maximum amount of time that can be queued.
      Since:
      1.20

    • getSize

      public long getSize()
      Get the size of the stream in bytes. A value of -1 means that the size is not known.
      Returns:
      the size of the stream previously set with gst_app_src_set_size();

    • getStreamType

      public AppStreamType getStreamType()
      Get the stream type. Control the stream type of this AppSrc with gst_app_src_set_stream_type().
      Returns:
      the stream type.

    • pushBuffer

      public FlowReturn pushBuffer(Buffer buffer)

      Adds a buffer to the queue of buffers that the appsrc element will push to its source pad. This function takes ownership of the buffer.

      When the block property is TRUE, this function can block until free space becomes available in the queue.

      Parameters:
      buffer - a GstBuffer to push
      Returns:
      GST_FLOW_OK when the buffer was successfully queued. GST_FLOW_FLUSHING when this AppSrc is not PAUSED or PLAYING. GST_FLOW_EOS when EOS occurred.

    • pushBufferList

      public FlowReturn pushBufferList(BufferList bufferList)

      Adds a buffer list to the queue of buffers and buffer lists that the appsrc element will push to its source pad. This function takes ownership of bufferList.

      When the block property is TRUE, this function can block until free space becomes available in the queue.

      Parameters:
      bufferList - a GstBufferList to push
      Returns:
      GST_FLOW_OK when the buffer list was successfully queued. GST_FLOW_FLUSHING when this AppSrc is not PAUSED or PLAYING. GST_FLOW_EOS when EOS occurred.
      Since:
      1.14

    • pushSample

      public FlowReturn pushSample(Sample sample)

      Extract a buffer from the provided sample and adds it to the queue of buffers that the appsrc element will push to its source pad. Any previous caps that were set on appsrc will be replaced by the caps associated with the sample if not equal.

      This function does not take ownership of the sample so the sample needs to be unreffed after calling this function.

      When the block property is TRUE, this function can block until free space becomes available in the queue.

      Parameters:
      sample - a GstSample from which buffer and caps may be extracted
      Returns:
      GST_FLOW_OK when the buffer was successfully queued. GST_FLOW_FLUSHING when this AppSrc is not PAUSED or PLAYING. GST_FLOW_EOS when EOS occurred.
      Since:
      1.6

    • setCallbacks

      public void setCallbacks(AppSrcCallbacks callbacks, @Nullable MemorySegment userData)

      Set callbacks which will be executed when data is needed, enough data has been collected or when a seek should be performed. This is an alternative to using the signals, it has lower overhead and is thus less expensive, but also less flexible.

      If callbacks are installed, no signals will be emitted for performance reasons.

      Before 1.16.3 it was not possible to change the callbacks in a thread-safe way.

      Parameters:
      callbacks - the callbacks
      userData - a user_data argument for the callbacks

    • setCapabilities

      public void setCapabilities(@Nullable Caps caps)
      Set the capabilities on the appsrc element. This function takes a copy of the caps structure. After calling this method, the source will only produce caps that match caps. caps must be fixed and the caps on the buffers must match the caps or left NULL.
      Parameters:
      caps - caps to set

    • setDuration

      public void setDuration(ClockTime duration)
      Set the duration of the stream in nanoseconds. A value of GST_CLOCK_TIME_NONE means that the duration is not known.
      Parameters:
      duration - the duration to set
      Since:
      1.10

    • setEmitSignals

      public void setEmitSignals(boolean emit)
      Make appsrc emit the "new-preroll" and "new-buffer" signals. This option is by default disabled because signal emission is expensive and unneeded when the application prefers to operate in pull mode.
      Parameters:
      emit - the new state

    • setLatency

      public void setLatency(long min, long max)
      Configure the min and max latency in src. If min is set to -1, the default latency calculations for pseudo-live sources will be used.
      Parameters:
      min - the min latency
      max - the max latency

    • setLeakyType

      public void setLeakyType(AppLeakyType leaky)
      When set to any other value than GST_APP_LEAKY_TYPE_NONE then the appsrc will drop any buffers that are pushed into it once its internal queue is full. The selected type defines whether to drop the oldest or new buffers.
      Parameters:
      leaky - the GstAppLeakyType
      Since:
      1.20

    • setMaxBuffers

      public void setMaxBuffers(long max)
      Set the maximum amount of buffers that can be queued in appsrc. After the maximum amount of buffers are queued, this AppSrc will emit the "enough-data" signal.
      Parameters:
      max - the maximum number of buffers to queue
      Since:
      1.20

    • setMaxBytes

      public void setMaxBytes(long max)
      Set the maximum amount of bytes that can be queued in appsrc. After the maximum amount of bytes are queued, this AppSrc will emit the "enough-data" signal.
      Parameters:
      max - the maximum number of bytes to queue

    • setMaxTime

      public void setMaxTime(ClockTime max)
      Set the maximum amount of time that can be queued in appsrc. After the maximum amount of time are queued, this AppSrc will emit the "enough-data" signal.
      Parameters:
      max - the maximum amonut of time to queue
      Since:
      1.20

    • setSize

      public void setSize(long size)
      Set the size of the stream in bytes. A value of -1 means that the size is not known.
      Parameters:
      size - the size to set

    • setStreamType

      public void setStreamType(AppStreamType type)

      Set the stream type on appsrc. For seekable streams, the "seek" signal must be connected to.

      A stream_type stream

      Parameters:
      type - the new state

    • enoughData

      protected void enoughData()

    • needData

      protected void needData(int length)

    • seekData

      protected boolean seekData(long offset)

    • onEndOfStream

      public SignalConnection<AppSrc.EndOfStreamCallback> onEndOfStream(AppSrc.EndOfStreamCallback handler)
      Notify appsrc that no more buffer are available.
      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitEndOfStream

      public FlowReturn emitEndOfStream()
      Emits the "end-of-stream" signal. See onEndOfStream(AppSrc.EndOfStreamCallback).

    • onEnoughData

      public SignalConnection<AppSrc.EnoughDataCallback> onEnoughData(AppSrc.EnoughDataCallback handler)
      Signal that the source has enough data. It is recommended that the application stops calling push-buffer until the need-data signal is emitted again to avoid excessive buffer queueing.
      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitEnoughData

      public void emitEnoughData()
      Emits the "enough-data" signal. See onEnoughData(AppSrc.EnoughDataCallback).

    • onNeedData

      public SignalConnection<AppSrc.NeedDataCallback> onNeedData(AppSrc.NeedDataCallback handler)

      Signal that the source needs more data. In the callback or from another thread you should call push-buffer or end-of-stream.

      length is just a hint and when it is set to -1, any number of bytes can be pushed into appsrc.

      You can call push-buffer multiple times until the enough-data signal is fired.

      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitNeedData

      public void emitNeedData(int length)
      Emits the "need-data" signal. See onNeedData(AppSrc.NeedDataCallback).

    • onPushBuffer

      public SignalConnection<AppSrc.PushBufferCallback> onPushBuffer(AppSrc.PushBufferCallback handler)

      Adds a buffer to the queue of buffers that the appsrc element will push to its source pad.

      This function does not take ownership of the buffer, but it takes a reference so the buffer can be unreffed at any time after calling this function.

      When the block property is TRUE, this function can block until free space becomes available in the queue.

      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitPushBuffer

      public FlowReturn emitPushBuffer(@Nullable Buffer buffer)
      Emits the "push-buffer" signal. See onPushBuffer(AppSrc.PushBufferCallback).

    • onPushBufferList

      public SignalConnection<AppSrc.PushBufferListCallback> onPushBufferList(AppSrc.PushBufferListCallback handler)

      Adds a buffer list to the queue of buffers and buffer lists that the appsrc element will push to its source pad.

      This function does not take ownership of the buffer list, but it takes a reference so the buffer list can be unreffed at any time after calling this function.

      When the block property is TRUE, this function can block until free space becomes available in the queue.

      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      Since:
      1.14
      See Also:

    • emitPushBufferList

      public FlowReturn emitPushBufferList(@Nullable BufferList bufferList)
      Emits the "push-buffer-list" signal. See onPushBufferList(AppSrc.PushBufferListCallback).

    • onPushSample

      public SignalConnection<AppSrc.PushSampleCallback> onPushSample(AppSrc.PushSampleCallback handler)

      Extract a buffer from the provided sample and adds the extracted buffer to the queue of buffers that the appsrc element will push to its source pad. This function set the appsrc caps based on the caps in the sample and reset the caps if they change. Only the caps and the buffer of the provided sample are used and not for example the segment in the sample.

      This function does not take ownership of the sample, but it takes a reference so the sample can be unreffed at any time after calling this function.

      When the block property is TRUE, this function can block until free space becomes available in the queue.

      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      Since:
      1.6
      See Also:

    • emitPushSample

      public FlowReturn emitPushSample(@Nullable Sample sample)
      Emits the "push-sample" signal. See onPushSample(AppSrc.PushSampleCallback).

    • onSeekData

      public SignalConnection<AppSrc.SeekDataCallback> onSeekData(AppSrc.SeekDataCallback handler)
      Seek to the given offset. The next push-buffer should produce buffers from the new offset. This callback is only called for seekable stream types.
      Parameters:
      handler - the signal handler
      Returns:
      a signal handler ID to keep track of the signal connection
      See Also:

    • emitSeekData

      public boolean emitSeekData(long offset)
      Emits the "seek-data" signal. See onSeekData(AppSrc.SeekDataCallback).

    • builder

      public static AppSrc.Builder<? extends AppSrc.Builder> builder()
      A AppSrc.Builder object constructs a AppSrc with the specified properties. Use the various set...() methods to set properties, and finish construction with AppSrc.Builder.build().
      Returns:
      the builder object