Porting PocketSphinx GStreamer to Vala

[Brian Duffy]

Hello all,

I am trying to port this
example "Using PocketSphinx with GStreamer and Python" to Vala. I have an
example compiling but I am getting some warnings that I don't understand and a
segmentation fault when running. Also, I am not sure what data types I should
be using for the "text" and "uttid" params in the asrResult ,
asrPartialResult, partialResult and finalResult methods.

My environment is Fedora 16. PocketSphinx .7, latest gstreamer that comes with
Fedora 16. I am using Clutter for the main loop because my application UI will
ultimately be written in Clutter. Any help would be greatly appreciated. Here
are my compile warnings and code .... thanks.

$ valac -X -O2 -g --pkg clutter-1.0 --pkg gstreamer-0.10 --pkg gstreamer-
interfaces-0.10 --pkg clutter-gst-1.0 cmu.vala
cmu.vala:25.24-25.48: warning: unhandled error GLib.Error' pipeline = (Pipeline)Gst.parse_launch(pipeDef); ^^^^^^^^^^^^^^^^^^^^^^^^^ cmu.vala:11.2-11.26: warning: fieldSphinx.vader' never used
private Gst.Element vader;
^^^^^^^^^^^^^^^^^^^^^^^^^
cmu.vala:112.6-112.26: warning: local variable `sphinx' declared but never
used
var sphinx = new Sphinx();
^^^^^^^^^^^^^^^^^^^^^
/home/brian/BitBucketRepos/foodie/cmu.vala: In function
‘sphinx_asrPartialResult’:
/home/brian/BitBucketRepos/foodie/cmu.vala:51:2: warning: passing argument 1
of ‘gst_structure_set_value’ discards ‘const’ qualifier from pointer target
type
/usr/include/gstreamer-0.10/gst/gststructure.h:117:25: note: expected ‘struct
GstStructure ’ but argument is of type ‘const struct GstStructure ’
/home/brian/BitBucketRepos/foodie/cmu.vala:52:2: warning: passing argument 1
of ‘gst_structure_set_value’ discards ‘const’ qualifier from pointer target
type
/usr/include/gstreamer-0.10/gst/gststructure.h:117:25: note: expected ‘struct
GstStructure ’ but argument is of type ‘const struct GstStructure ’
/home/brian/BitBucketRepos/foodie/cmu.vala:54:2: warning: passing argument 1
of ‘_gst_structure_copy0’ discards ‘const’ qualifier from pointer target type
cmu.vala.c:287:17: note: expected ‘gpointer’ but argument is of type ‘const
struct GstStructure ’
/home/brian/BitBucketRepos/foodie/cmu.vala: In function ‘sphinx_asrResult’:
/home/brian/BitBucketRepos/foodie/cmu.vala:65:2: warning: passing argument 1
of ‘gst_structure_set_value’ discards ‘const’ qualifier from pointer target
type
/usr/include/gstreamer-0.10/gst/gststructure.h:117:25: note: expected ‘struct
GstStructure ’ but argument is of type ‘const struct GstStructure ’
/home/brian/BitBucketRepos/foodie/cmu.vala:66:2: warning: passing argument 1
of ‘gst_structure_set_value’ discards ‘const’ qualifier from pointer target
type
/usr/include/gstreamer-0.10/gst/gststructure.h:117:25: note: expected ‘struct
GstStructure ’ but argument is of type ‘const struct GstStructure ’
/home/brian/BitBucketRepos/foodie/cmu.vala:68:2: warning: passing argument 1
of ‘_gst_structure_copy0’ discards ‘const’ qualifier from pointer target type
cmu.vala.c:287:17: note: expected ‘gpointer’ but argument is of type ‘const
struct GstStructure ’
/home/brian/BitBucketRepos/foodie/cmu.vala: In function ‘sphinx_app_message’:
/home/brian/BitBucketRepos/foodie/cmu.vala:77:2: warning: passing argument 1
of ‘_gst_structure_copy0’ discards ‘const’ qualifier from pointer target type
cmu.vala.c:287:17: note: expected ‘gpointer’ but argument is of type ‘const
struct GstStructure *’
cmu.vala.c: In function ‘_vala_main’:
/home/brian/BitBucketRepos/foodie/cmu.vala:107:15: warning: ignoring return
value of ‘clutter_init’, declared with attribute warn_unused_result
Compilation succeeded - 3 warning(s)

using Clutter;
using ClutterGst;
using Gst;


class Sphinx : GLib.Object {


    // experimenting with gstreamer pocketsphinx
    private Gst.Pipeline pipeline;
    private Gst.Element vader;
    dynamic Gst.Element asr;
    private Gst.Bus bus;
    private Gst.Structure msg;
    private Gst.Structure my_struct;

    public Sphinx() {


        string a = """pulsesrc device="alsa_input.usb-AKM_AK5370-00-AK5370.analog-mono" ! audioconvert !""";
        string b = """ audioresample ! vader name=vad auto-threshold=true ! pocketsphinx name=asr ! fakesink""";


        string pipeDef = a + b;
        pipeline = (Pipeline)Gst.parse_launch(pipeDef);

        asr = pipeline.get_by_name("asr");

        asr.set_property("lm", "4038.lm");
        asr.set_property("dict", "4038.dic");

        asr.partial_result.connect(asrPartialResult);
        asr.result.connect(asrResult);

        asr.set_property("configured", true);

        bus = pipeline.get_bus();
        bus.add_signal_watch();
        bus.message.connect(app_message);

        pipeline.set_state(Gst.State.PLAYING);


    }


    private void asrPartialResult(Gst.Element asr, GLib.Value text, GLib.Value uttid) {

        my_struct = new Gst.Structure.empty("partial_result");

        my_struct.set_value("hyp", text);
        my_struct.set_value("uttid", uttid);

        asr.post_message(new Gst.Message.application(asr, my_struct));

    }


    private void asrResult(Gst.Element asr, GLib.Value text, GLib.Value uttid) {

        stdout.printf("%s", "inside asrResult");

        my_struct = new Gst.Structure.empty("result");

        my_struct.set_value("hyp", text);
        my_struct.set_value("uttid", uttid);

        asr.post_message(new Gst.Message.application(asr, my_struct));

    }


    private void app_message(Gst.Bus bus, Gst.Message p_msg) {


        //stdout.printf("%s", "inside app_message");
        msg = p_msg.get_structure();

        string msgType = msg.get_name();

        if (msgType == "partial_result") {
            partialResult(msg["hyp"], msg["uttid"]);
        }else if (msgType == "result") {
            finalResult(msg["hyp"], msg["uttid"]);
            pipeline.set_state(Gst.State.PAUSED);
        }


    }


    private void partialResult(GLib.Value hyp, GLib.Value uttid) {

        stdout.printf("%s", (string)hyp);
    }

    private void finalResult(GLib.Value hyp, GLib.Value uttid) {
        stdout.printf("%s", (string)hyp);
    }


}


int main (string[] args) {

    Clutter.init(ref args);
    Gst.init(ref args);

    //ClutterGst.init(ref args);

    var sphinx = new Sphinx();

    Clutter.main();

    return 0;
}

[Nickolay V. Shmyrev]

Thanks for interesting feature. I suppose the working example is here

http://cmusphinx.sourceforge.net/wiki/gstreamer