/* * audio-example.c * * Build a pipeline with testaudiosource->alsasink * and sweep frequency and volume * */ #include #include 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); }