diff options
Diffstat (limited to 'gst/level/level-example.c')
-rw-r--r-- | gst/level/level-example.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/gst/level/level-example.c b/gst/level/level-example.c new file mode 100644 index 00000000..dcfdec0c --- /dev/null +++ b/gst/level/level-example.c @@ -0,0 +1,89 @@ +#include <string.h> +#include <math.h> + +#include <gst/gst.h> + +gboolean +message_handler (GstBus * bus, GstMessage * message, gpointer data) +{ + + if (message->type == GST_MESSAGE_APPLICATION) { + const GstStructure *s = gst_message_get_structure (message); + const gchar *name = gst_structure_get_name (s); + + if (strcmp (name, "level") == 0) { + gint channels; + gdouble endtime, rms_dB, peak_dB, decay_dB; + gdouble rms; + const GValue *list; + const GValue *value; + + if (!gst_structure_get_double (s, "endtime", &endtime)) + g_warning ("Could not parse endtime"); + list = gst_structure_get_value (s, "rms"); + /* we can get the number of channels as the length of any of the value + * lists */ + channels = gst_value_list_get_size (list); + + /* we will only get values for the first channel, since we know sinesrc + * is mono */ + value = gst_value_list_get_value (list, 0); + rms_dB = g_value_get_double (value); + list = gst_structure_get_value (s, "peak"); + value = gst_value_list_get_value (list, 0); + peak_dB = g_value_get_double (value); + list = gst_structure_get_value (s, "decay"); + value = gst_value_list_get_value (list, 0); + decay_dB = g_value_get_double (value); + g_print ("endtime: %f, channels: %d\n", endtime, channels); + g_print ("RMS: %f dB, peak: %f dB, decay: %f dB\n", + rms_dB, peak_dB, decay_dB); + + /* converting from dB to normal gives us a value between 0.0 and 1.0 */ + rms = pow (10, rms_dB / 20); + g_print ("normalized rms value: %f\n", rms); + } + } + /* we handled the message we want, and ignored the ones we didn't want. + * so the core can unref the message for us */ + return TRUE; +} + +int +main (int argc, char *argv[]) +{ + GstElement *sinesrc, *level, *fakesink; + GstElement *pipeline; + GstBus *bus; + gint watch_id; + GMainLoop *loop; + + gst_init (&argc, &argv); + + pipeline = gst_pipeline_new (NULL); + g_assert (pipeline); + sinesrc = gst_element_factory_make ("sinesrc", NULL); + g_assert (sinesrc); + level = gst_element_factory_make ("level", NULL); + g_assert (level); + fakesink = gst_element_factory_make ("fakesink", NULL); + g_assert (fakesink); + + gst_bin_add_many (GST_BIN (pipeline), sinesrc, level, fakesink, NULL); + gst_element_link (sinesrc, level); + gst_element_link (level, fakesink); + + /* make sure we'll get messages */ + g_object_set (G_OBJECT (level), "message", TRUE, NULL); + + bus = gst_element_get_bus (pipeline); + watch_id = gst_bus_add_watch (bus, message_handler, NULL); + + gst_element_set_state (pipeline, 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); + + return 0; +} |