GStreamer-devel

Dynamically add and remove audio sink

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Nagy István

Dynamically add and remove audio sink

Hello everyone!

I'm very new to GStreamer, i'm experimenting with the framework since a week. My current goal would be to write a radio scheduler application which can handle audio playback required for a web radio, stream the result with different encoders and optionally do audio output on a local audio hardware.

I did some tests about how can i plugin different sources to an Adder so i can use the pipeline as an audio mixer. After finding the pad blocking capability of GStreamer, i could add and remove audio sources into the pipeline without stopping it. http://stackoverflow.com/questions/3899666/adding-and-removing-audio-sources-to-from-gstreamer-pipeline-on-the-go I want to do this with the audio outputs as well, i like to add and remove different audio sinks while the pipeline is running.

I've added a Tee after the Adder so i can split up sources to many outputs. If i fire up the pipeline with an autoaudiosink (with it's own queue), playback works fine. If i add a fakesink to the Tee's output on the go (requesting a new src request pad an linking it with an another queue in the middle), one of my audio sources pauses the pipeline with a

basesrc gstbasesrc.c:2447:gst_base_src_loop:<Buzzer1> pausing after gst_pad_push() = wrong-state

error message in the debug output.

I've tried to put a block on the Adder's source output while adding the new audio sink, but it wouldn't help me.

Here is the code i'm working with), it's the Java rewrite of the StackOverflow Python script what i linked above. I don't know what to try next. If i put the pipeline together with two sinks before the first start, everything works fine.

package test;

import java.io.IOException;

import java.util.logging.Level;

import java.util.logging.Logger;

import org.gstreamer.Element;

import org.gstreamer.ElementFactory;

import org.gstreamer.Gst;

import org.gstreamer.Pad;

import org.gstreamer.Pipeline;

import org.gstreamer.State;

public class Main {

public static void main(String[] args) {

Gst.init("RadioBeans", args);

Pipeline pipe = new Pipeline("Scheduler");

Element mixer = ElementFactory.make("adder", "Mixer");

pipe.add(mixer);

Element tee = ElementFactory.make("tee", "Splitter");

pipe.add(tee);

mixer.link(tee);

Element audioSink = ElementFactory.make("autoaudiosink","AudioOutput");

pipe.add(audioSink);

Element audioQueue = ElementFactory.make("queue","AudioQueue");

pipe.add(audioQueue);

tee.link(audioQueue);

audioQueue.link(audioSink);

Pad mixerLine1=mixer.getRequestPad("sink%d");

Pad mixerLine2=mixer.getRequestPad("sink%d");

Element buzzer1 = ElementFactory.make("audiotestsrc", "Buzzer1");

pipe.add(buzzer1);

buzzer1.set("freq", 1000);

Pad buzzer1src=buzzer1.getSrcPads().get(0);

buzzer1src.link(mixerLine1);

Element buzzer2 = ElementFactory.make("audiotestsrc", "Buzzer2");

pipe.add(buzzer2);

buzzer2.set("freq", 500);

Pad buzzer2src=buzzer2.getSrcPads().get(0);

buzzer2src.link(mixerLine2);

pipe.play();

try {

System.in.read();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

Element fakeOutput = ElementFactory.make("fakesink", "FakeOutput");

pipe.add(fakeOutput);

Element fakeQueue = ElementFactory.make("queue","FakeQueue");

pipe.add(fakeQueue);

fakeQueue.link(fakeOutput);

tee.link(fakeQueue);

pipe.play();

System.out.println("Added fakesink");

try {

System.in.read();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

buzzer1src.setBlocked(true);

buzzer1.setState(State.NULL);

buzzer1src.unlink(mixerLine1);

mixer.releaseRequestPad(mixerLine1);

System.out.println("Released buzzer1");

try {

System.in.read();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

System.out.println("Stopping.");

pipe.stop();

}

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Gruenke, Matt

Re: Dynamically add and remove audio sink

When you add an element to a bin, you must match its state to that of the bin.

I think the proper sequence is:

add the element to the bin (keep in mind that a pipeline is just a special kind of bin)
call gst_element_sync_state_with_parent() on the newly-added element
link in the element

When I add a branch to a tee, I put everything on that branch in its own bin. That way, on addition & removal, I’m just dealing with that one bin.

Matt

From: Nagy István [mailto:[hidden email]]
Sent: Thursday, October 14, 2010 18:02
To: [hidden email]
Subject: [gst-devel] Dynamically add and remove audio sink

Hello everyone!

basesrc gstbasesrc.c:2447:gst_base_src_loop:<Buzzer1> pausing after gst_pad_push() = wrong-state

error message in the debug output.

I've tried to put a block on the Adder's source output while adding the new audio sink, but it wouldn't help me.

package test;

import java.io.IOException;

import java.util.logging.Level;

import java.util.logging.Logger;

import org.gstreamer.Element;

import org.gstreamer.ElementFactory;

import org.gstreamer.Gst;

import org.gstreamer.Pad;

import org.gstreamer.Pipeline;

import org.gstreamer.State;

public class Main {

public static void main(String[] args) {

Gst.init("RadioBeans", args);

Pipeline pipe = new Pipeline("Scheduler");

Element mixer = ElementFactory.make("adder", "Mixer");

pipe.add(mixer);

Element tee = ElementFactory.make("tee", "Splitter");

pipe.add(tee);

mixer.link(tee);

Element audioSink = ElementFactory.make("autoaudiosink","AudioOutput");

pipe.add(audioSink);

Element audioQueue = ElementFactory.make("queue","AudioQueue");

pipe.add(audioQueue);

tee.link(audioQueue);

audioQueue.link(audioSink);

Pad mixerLine1=mixer.getRequestPad("sink%d");

Pad mixerLine2=mixer.getRequestPad("sink%d");

Element buzzer1 = ElementFactory.make("audiotestsrc", "Buzzer1");

pipe.add(buzzer1);

buzzer1.set("freq", 1000);

Pad buzzer1src=buzzer1.getSrcPads().get(0);

buzzer1src.link(mixerLine1);

Element buzzer2 = ElementFactory.make("audiotestsrc", "Buzzer2");

pipe.add(buzzer2);

buzzer2.set("freq", 500);

Pad buzzer2src=buzzer2.getSrcPads().get(0);

buzzer2src.link(mixerLine2);

pipe.play();

try {

System.in.read();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

Element fakeOutput = ElementFactory.make("fakesink", "FakeOutput");

pipe.add(fakeOutput);

Element fakeQueue = ElementFactory.make("queue","FakeQueue");

pipe.add(fakeQueue);

fakeQueue.link(fakeOutput);

tee.link(fakeQueue);

pipe.play();

System.out.println("Added fakesink");

try {

System.in.read();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

buzzer1src.setBlocked(true);

buzzer1.setState(State.NULL);

buzzer1src.unlink(mixerLine1);

mixer.releaseRequestPad(mixerLine1);

System.out.println("Released buzzer1");

try {

System.in.read();

} catch (IOException ex) {

Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

}

System.out.println("Stopping.");

pipe.stop();

}

Nagy István

Re: Dynamically add and remove audio sink

Thank you Matt!

I did it as you said and it worked like a charm. :)

I had to enable synchronization on fakesink if i add that first to the tee before playback. If i don't do so i can't connect an autoaudiosink while the pipeline is running. I get a buffer overflow error from the new sink. I guess fakesink starts in non realtime mode as a default.

István

On Fri, Oct 15, 2010 at 6:24 AM, Gruenke, Matt <[hidden email]> wrote:

When you add an element to a bin, you must match its state to that of the bin.

I think the proper sequence is:

add the element to the bin (keep in mind that a pipeline is just a special kind of bin)

call gst_element_sync_state_with_parent() on the newly-added element

link in the element

When I add a branch to a tee, I put everything on that branch in its own bin. That way, on addition & removal, I’m just dealing with that one bin.

Matt

From: Nagy István [mailto:[hidden email]]
Sent: Thursday, October 14, 2010 18:02
To: [hidden email]
Subject: [gst-devel] Dynamically add and remove audio sink

Hello everyone!

I'm very new to GStreamer, i'm experimenting with the framework since a week. My current goal would be to write a radio scheduler application which can handle audio playback required for a web radio, stream the result with different encoders and optionally do audio output on a local audio hardware.

I did some tests about how can i plugin different sources to an Adder so i can use the pipeline as an audio mixer. After finding the pad blocking capability of GStreamer, i could add and remove audio sources into the pipeline without stopping it. http://stackoverflow.com/questions/3899666/adding-and-removing-audio-sources-to-from-gstreamer-pipeline-on-the-go I want to do this with the audio outputs as well, i like to add and remove different audio sinks while the pipeline is running.

I've added a Tee after the Adder so i can split up sources to many outputs. If i fire up the pipeline with an autoaudiosink (with it's own queue), playback works fine. If i add a fakesink to the Tee's output on the go (requesting a new src request pad an linking it with an another queue in the middle), one of my audio sources pauses the pipeline with a

basesrc gstbasesrc.c:2447:gst_base_src_loop:<Buzzer1> pausing after gst_pad_push() = wrong-state

error message in the debug output.

I've tried to put a block on the Adder's source output while adding the new audio sink, but it wouldn't help me.

Here is the code i'm working with), it's the Java rewrite of the StackOverflow Python script what i linked above. I don't know what to try next. If i put the pipeline together with two sinks before the first start, everything works fine.

package test;

import java.io.IOException;

import java.util.logging.Level;

import java.util.logging.Logger;

import org.gstreamer.Element;

import org.gstreamer.ElementFactory;

import org.gstreamer.Gst;

import org.gstreamer.Pad;

import org.gstreamer.Pipeline;

import org.gstreamer.State;

public class Main {

   public static void main(String[] args) {

   Gst.init("RadioBeans", args);

   Pipeline pipe = new Pipeline("Scheduler");

   Element mixer = ElementFactory.make("adder", "Mixer");

   pipe.add(mixer);

   Element tee = ElementFactory.make("tee", "Splitter");

   pipe.add(tee);

   mixer.link(tee);

   Element audioSink = ElementFactory.make("autoaudiosink","AudioOutput");

   pipe.add(audioSink);

   Element audioQueue = ElementFactory.make("queue","AudioQueue");

   pipe.add(audioQueue);

   tee.link(audioQueue);

   audioQueue.link(audioSink);

   Pad mixerLine1=mixer.getRequestPad("sink%d");

   Pad mixerLine2=mixer.getRequestPad("sink%d");

   Element buzzer1 = ElementFactory.make("audiotestsrc", "Buzzer1");

   pipe.add(buzzer1);

   buzzer1.set("freq", 1000);

   Pad buzzer1src=buzzer1.getSrcPads().get(0);

   buzzer1src.link(mixerLine1);



   Element buzzer2 = ElementFactory.make("audiotestsrc", "Buzzer2");

   pipe.add(buzzer2);

   buzzer2.set("freq", 500);

   Pad buzzer2src=buzzer2.getSrcPads().get(0);

   buzzer2src.link(mixerLine2);

   pipe.play();

   try {

   System.in.read();

   } catch (IOException ex) {

   Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

   }

   Element fakeOutput = ElementFactory.make("fakesink", "FakeOutput");

   pipe.add(fakeOutput);

   Element fakeQueue = ElementFactory.make("queue","FakeQueue");

   pipe.add(fakeQueue);

   fakeQueue.link(fakeOutput);

   tee.link(fakeQueue);

   pipe.play();

   System.out.println("Added fakesink");

   try {

   System.in.read();

   } catch (IOException ex) {

   Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

   }

   buzzer1src.setBlocked(true);

   buzzer1.setState(State.NULL);

   buzzer1src.unlink(mixerLine1);

   mixer.releaseRequestPad(mixerLine1);

   System.out.println("Released buzzer1");

   try {

   System.in.read();

   } catch (IOException ex) {

   Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);

   }

   System.out.println("Stopping.");

   pipe.stop();

   }

}

------------------------------------------------------------------------------
Download new Adobe(R) Flash(R) Builder(TM) 4
The new Adobe(R) Flex(R) 4 and Flash(R) Builder(TM) 4 (formerly
Flex(R) Builder(TM)) enable the development of rich applications that run
across multiple browsers and platforms. Download your free trials today!
http://p.sf.net/sfu/adobe-dev2dev
_______________________________________________
gstreamer-devel mailing list
[hidden email]
https://lists.sourceforge.net/lists/listinfo/gstreamer-devel