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

[Stefan Kost]

Guilherme Raymo Longo schrieb:
> 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.....!

if you do
gst-launch alsasrc num-buffers=100 ! wavenc ! filesink location=test.wav
and you make some noise. Does the resulting wav file has sound (or noise
:) ) or is it silent?

Stefan
>
>
> 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 <mailto:grlongo.ireland at hotmail.com>
> skype: grlongo.ireland
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