[gst-devel] spectrum plug-in not working properly with alsasrc

[Guilherme Raymo Longo]

Good morning mates.

I've been working on this code over a month and I can't figure out what is
wrong with it.

I am developing a spectrum analyser and as a first step the program is
capturing sound from alsa and analysing the sound using the spectrum
plug-in.

If I use audiotestsrc, I get the results on screen as expected, when I
change to alsasrc, I still get the results on screen but without
modification, as if I didn't have any sound comming from my microfone.
Its is strange 'cause my mic is working pretty well since I am able to
record sound.

I was wondering if someone could gimme some help here.....!


Thanks in advanced...



#include <string.h>
#include <stdlib.h>
#include <gst/gst.h>

static guint spect_bands = 20;

#define AUDIOFREQ 44100

/* receive spectral data from element message */
gboolean
message_handler (GstBus * bus, GstMessage * message, gpointer data)
{
  if (message->type == GST_MESSAGE_ELEMENT) {
    const GstStructure *s = gst_message_get_structure (message);
    const gchar *name = gst_structure_get_name (s);
    GstClockTime endtime;

    if (strcmp (name, "spectrum") == 0) {
      const GValue *magnitudes;
      const GValue *phases;
      const GValue *mag, *phase;
      gdouble freq;
      guint i;

      if (!gst_structure_get_clock_time (s, "endtime", &endtime))
        endtime = GST_CLOCK_TIME_NONE;

      g_print ("New spectrum message, endtime %" GST_TIME_FORMAT "\n",
          GST_TIME_ARGS (endtime));

      magnitudes = gst_structure_get_value (s, "magnitude");
      phases = gst_structure_get_value (s, "phase");

      for (i = 0; i < spect_bands; ++i) {
        freq = (gdouble) ((AUDIOFREQ / 2) * i + AUDIOFREQ / 4) /
spect_bands;
        mag = gst_value_list_get_value (magnitudes, i);
        phase = gst_value_list_get_value (phases, i);

        if (mag != NULL && phase != NULL) {
          g_print ("band %d (freq %g): magnitude %f dB phase %f\n", i, freq,
              g_value_get_float (mag), g_value_get_float (phase));
        }
      }
      g_print ("\n");
    }
  }
  return TRUE;
}

int
main (int argc, char *argv[])
{
  GstElement *bin;
  GstElement *src, *spectrum, *sink;
  GstBus *bus;
  GMainLoop *loop;

  gst_init (&argc, &argv);

  bin = gst_pipeline_new ("bin");

  src = gst_element_factory_make ("audiotestsrc", "src");

  spectrum = gst_element_factory_make ("spectrum", "spectrum");
  g_object_set (G_OBJECT (spectrum), "bands", spect_bands,
      "message", TRUE, "message-phase", TRUE, NULL);

  sink = gst_element_factory_make ("fakesink", "sink");
  g_object_set (G_OBJECT (sink), "sync", TRUE, NULL);

  gst_bin_add_many (GST_BIN (bin), src, spectrum, sink, NULL);


  if (!gst_element_link (src, spectrum) ||
      !gst_element_link (spectrum, sink)) {
    fprintf (stderr, "can't link elements\n");
    exit (1);
  }


 bus = gst_element_get_bus (bin);
  gst_bus_add_watch (bus, message_handler, NULL);
  gst_object_unref (bus);

  gst_element_set_state (bin, GST_STATE_PLAYING);

  /* we need to run a GLib main loop to get the messages */
  loop = g_main_loop_new (NULL, FALSE);
  g_main_loop_run (loop);

  gst_element_set_state (bin, GST_STATE_NULL);

  gst_object_unref (bin);

  return 0;
}
-- 
Guilherme Raymo Longo
Software Developer
Mob. 087 - 3179008
msn: grlongo.ireland at hotmail.com
skype: grlongo.ireland
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