gstreamer/tests/examples/controller/audio-example.c

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/*
* audio-example.c
*
* Build a pipeline with testaudiosource->alsasink
* and sweep frequency and volume
*
*/
#include <gst/gst.h>
#include <gst/controller/gstcontroller.h>
gint
main (gint argc, gchar ** argv)
{
gint res = 1;
GstElement *src, *sink;
GstElement *bin;
GstController *ctrl;
GstClock *clock;
GstClockID clock_id;
GstClockReturn wait_ret;
GValue vol = { 0, };
gst_init (&argc, &argv);
gst_controller_init (&argc, &argv);
/* build pipeline */
bin = gst_pipeline_new ("pipeline");
clock = gst_pipeline_get_clock (GST_PIPELINE (bin));
src = gst_element_factory_make ("audiotestsrc", "gen_audio");
sink = gst_element_factory_make ("alsasink", "play_audio");
gst_bin_add_many (GST_BIN (bin), src, sink, NULL);
if (!gst_element_link (src, sink)) {
GST_WARNING ("can't link elements");
goto Error;
}
/* square wave
g_object_set (G_OBJECT(src), "wave", 1, NULL);
*/
/* add a controller to the source */
if (!(ctrl = gst_controller_new (G_OBJECT (src), "freq", "volume", NULL))) {
GST_WARNING ("can't control source element");
goto Error;
}
/* set interpolation */
gst_controller_set_interpolation_mode (ctrl, "volume",
GST_INTERPOLATE_LINEAR);
gst_controller_set_interpolation_mode (ctrl, "freq", GST_INTERPOLATE_LINEAR);
/* set control values */
g_value_init (&vol, G_TYPE_DOUBLE);
g_value_set_double (&vol, 0.0);
gst_controller_set (ctrl, "volume", 0 * GST_SECOND, &vol);
g_value_set_double (&vol, 1.0);
gst_controller_set (ctrl, "volume", 5 * GST_SECOND, &vol);
g_value_set_double (&vol, 220.0);
gst_controller_set (ctrl, "freq", 0 * GST_SECOND, &vol);
g_value_set_double (&vol, 3520.0);
gst_controller_set (ctrl, "freq", 3 * GST_SECOND, &vol);
g_value_set_double (&vol, 440.0);
gst_controller_set (ctrl, "freq", 6 * GST_SECOND, &vol);
clock_id =
gst_clock_new_single_shot_id (clock,
gst_clock_get_time (clock) + (7 * GST_SECOND));
/* run for 7 seconds */
if (gst_element_set_state (bin, GST_STATE_PLAYING)) {
if ((wait_ret = gst_clock_id_wait (clock_id, NULL)) != GST_CLOCK_OK) {
GST_WARNING ("clock_id_wait returned: %d", wait_ret);
}
gst_element_set_state (bin, GST_STATE_NULL);
}
/* cleanup */
g_object_unref (G_OBJECT (ctrl));
gst_object_unref (G_OBJECT (clock));
gst_object_unref (G_OBJECT (bin));
res = 0;
Error:
return (res);
}