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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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112 lines
3.1 KiB
C
112 lines
3.1 KiB
C
/*
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* audio-example.c
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*
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* Builds a pipeline with audiotestsource->alsasink and sweeps frequency and
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* volume.
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*
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* Needs gst-plugin-base installed.
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*/
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#include <gst/gst.h>
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#include <gst/controller/gstcontroller.h>
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#include <gst/controller/gstinterpolationcontrolsource.h>
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gint
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main (gint argc, gchar ** argv)
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{
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gint res = 1;
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GstElement *src, *sink;
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GstElement *bin;
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GstController *ctrl;
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GstInterpolationControlSource *csource1, *csource2;
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GstClock *clock;
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GstClockID clock_id;
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GstClockReturn wait_ret;
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GValue vol = { 0, };
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gst_init (&argc, &argv);
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gst_controller_init (&argc, &argv);
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/* build pipeline */
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bin = gst_pipeline_new ("pipeline");
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clock = gst_pipeline_get_clock (GST_PIPELINE (bin));
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src = gst_element_factory_make ("audiotestsrc", "gen_audio");
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if (!src) {
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GST_WARNING ("need audiotestsrc from gst-plugins-base");
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goto Error;
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}
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sink = gst_element_factory_make ("autoaudiosink", "play_audio");
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if (!sink) {
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GST_WARNING ("need autoaudiosink from gst-plugins-base");
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goto Error;
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}
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gst_bin_add_many (GST_BIN (bin), src, sink, NULL);
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if (!gst_element_link (src, sink)) {
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GST_WARNING ("can't link elements");
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goto Error;
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}
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/* square wave
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g_object_set (G_OBJECT(src), "wave", 1, NULL);
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*/
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/* add a controller to the source */
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if (!(ctrl = gst_controller_new (G_OBJECT (src), "freq", "volume", NULL))) {
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GST_WARNING ("can't control source element");
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goto Error;
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}
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csource1 = gst_interpolation_control_source_new ();
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csource2 = gst_interpolation_control_source_new ();
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gst_controller_set_control_source (ctrl, "volume",
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GST_CONTROL_SOURCE (csource1));
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gst_controller_set_control_source (ctrl, "freq",
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GST_CONTROL_SOURCE (csource2));
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/* Set interpolation mode */
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gst_interpolation_control_source_set_interpolation_mode (csource1,
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GST_INTERPOLATE_LINEAR);
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gst_interpolation_control_source_set_interpolation_mode (csource2,
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GST_INTERPOLATE_LINEAR);
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/* set control values */
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g_value_init (&vol, G_TYPE_DOUBLE);
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g_value_set_double (&vol, 0.0);
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gst_interpolation_control_source_set (csource1, 0 * GST_SECOND, &vol);
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g_value_set_double (&vol, 1.0);
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gst_interpolation_control_source_set (csource1, 5 * GST_SECOND, &vol);
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g_object_unref (csource1);
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g_value_set_double (&vol, 220.0);
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gst_interpolation_control_source_set (csource2, 0 * GST_SECOND, &vol);
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g_value_set_double (&vol, 3520.0);
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gst_interpolation_control_source_set (csource2, 3 * GST_SECOND, &vol);
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g_value_set_double (&vol, 440.0);
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gst_interpolation_control_source_set (csource2, 6 * GST_SECOND, &vol);
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g_object_unref (csource2);
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clock_id =
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gst_clock_new_single_shot_id (clock,
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gst_clock_get_time (clock) + (7 * GST_SECOND));
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/* run for 7 seconds */
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if (gst_element_set_state (bin, GST_STATE_PLAYING)) {
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if ((wait_ret = gst_clock_id_wait (clock_id, NULL)) != GST_CLOCK_OK) {
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GST_WARNING ("clock_id_wait returned: %d", wait_ret);
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}
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gst_element_set_state (bin, GST_STATE_NULL);
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}
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/* cleanup */
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g_object_unref (G_OBJECT (ctrl));
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gst_object_unref (G_OBJECT (clock));
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gst_object_unref (G_OBJECT (bin));
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res = 0;
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Error:
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return (res);
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}
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