| /* GStreamer |
| * |
| * sprinkle.c: sample application to dynamically mix tones with adder |
| * |
| * Copyright (C) <2009> Wim Taymans <wim dot taymans at gmail dot com> |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public |
| * License along with this library; if not, write to the |
| * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| */ |
| |
| /* |
| * Produces a sweeping sprinkle of tones by dynamically adding and removing |
| * elements to adder. |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include <gst/gst.h> |
| |
| static GstElement *pipeline, *adder; |
| static GMainLoop *loop; |
| |
| typedef struct |
| { |
| GstElement *element; |
| GstPad *srcpad; |
| GstPad *sinkpad; |
| gdouble freq; |
| } SourceInfo; |
| |
| /* dynamically add the source to the pipeline and link it to a new pad on |
| * adder */ |
| static SourceInfo * |
| add_source (gdouble freq) |
| { |
| SourceInfo *info; |
| |
| info = g_new0 (SourceInfo, 1); |
| info->freq = freq; |
| |
| /* make source with unique name */ |
| info->element = gst_element_factory_make ("audiotestsrc", NULL); |
| |
| g_object_set (info->element, "freq", freq, NULL); |
| |
| /* add to the bin */ |
| gst_bin_add (GST_BIN (pipeline), info->element); |
| |
| /* get pad from the element */ |
| info->srcpad = gst_element_get_static_pad (info->element, "src"); |
| |
| /* get new pad from adder, adder will now wait for data on this pad */ |
| info->sinkpad = gst_element_get_request_pad (adder, "sink_%u"); |
| |
| /* link pad to adder */ |
| gst_pad_link (info->srcpad, info->sinkpad); |
| |
| /* and play the element */ |
| gst_element_set_state (info->element, GST_STATE_PLAYING); |
| |
| g_print ("added freq %f\n", info->freq); |
| |
| return info; |
| } |
| |
| /* remove the source from the pipeline after removing it from adder */ |
| static void |
| remove_source (SourceInfo * info) |
| { |
| g_print ("remove freq %f\n", info->freq); |
| |
| /* lock the state so that we can put it to NULL without the parent messing |
| * with our state */ |
| gst_element_set_locked_state (info->element, TRUE); |
| |
| /* first stop the source. Remember that this might block when in the PAUSED |
| * state. Alternatively one could send EOS to the source, install an event |
| * probe and schedule a state change/unlink/release from the mainthread. |
| * Note that changing the state of a source makes it emit an EOS, which can |
| * make adder go EOS. */ |
| gst_element_set_state (info->element, GST_STATE_NULL); |
| |
| /* unlink from adder */ |
| gst_pad_unlink (info->srcpad, info->sinkpad); |
| gst_object_unref (info->srcpad); |
| |
| /* remove from the bin */ |
| gst_bin_remove (GST_BIN (pipeline), info->element); |
| |
| /* give back the pad */ |
| gst_element_release_request_pad (adder, info->sinkpad); |
| gst_object_unref (info->sinkpad); |
| |
| g_free (info); |
| } |
| |
| /* we'll keep the state of the sources in this structure. We keep 3 sources |
| * alive */ |
| typedef struct |
| { |
| guint count; |
| SourceInfo *infos[3]; |
| } SprinkleState; |
| |
| static SprinkleState * |
| create_state (void) |
| { |
| SprinkleState *state; |
| |
| state = g_new0 (SprinkleState, 1); |
| |
| return state; |
| } |
| |
| static void |
| free_state (SprinkleState * state) |
| { |
| SourceInfo *info; |
| gint i; |
| |
| for (i = 0; i < 3; i++) { |
| info = state->infos[i]; |
| if (info) |
| remove_source (info); |
| } |
| |
| g_free (state); |
| } |
| |
| static gboolean |
| do_sprinkle (SprinkleState * state) |
| { |
| SourceInfo *info; |
| gint i; |
| |
| /* first remove the oldest info */ |
| info = state->infos[2]; |
| |
| if (info) |
| remove_source (info); |
| |
| /* move sources */ |
| for (i = 2; i > 0; i--) { |
| state->infos[i] = state->infos[i - 1]; |
| } |
| |
| /* add new source, stop adding sources after 10 rounds. */ |
| if (state->count < 10) { |
| state->infos[0] = add_source ((state->count * 100) + 200); |
| state->count++; |
| } else { |
| state->infos[0] = NULL; |
| |
| /* if no more sources left, quit */ |
| if (!state->infos[2]) |
| g_main_loop_quit (loop); |
| } |
| |
| return TRUE; |
| } |
| |
| static void |
| message_received (GstBus * bus, GstMessage * message, GstPipeline * pipeline) |
| { |
| const GstStructure *s; |
| |
| s = gst_message_get_structure (message); |
| g_print ("message from \"%s\" (%s): ", |
| GST_STR_NULL (GST_ELEMENT_NAME (GST_MESSAGE_SRC (message))), |
| gst_message_type_get_name (GST_MESSAGE_TYPE (message))); |
| if (s) { |
| gchar *sstr; |
| |
| sstr = gst_structure_to_string (s); |
| g_print ("%s\n", sstr); |
| g_free (sstr); |
| } else { |
| g_print ("no message details\n"); |
| } |
| } |
| |
| static void |
| eos_message_received (GstBus * bus, GstMessage * message, |
| GstPipeline * pipeline) |
| { |
| message_received (bus, message, pipeline); |
| g_main_loop_quit (loop); |
| } |
| |
| int |
| main (int argc, char *argv[]) |
| { |
| GstBus *bus; |
| GstElement *filter, *convert, *sink; |
| GstCaps *caps; |
| gboolean linked; |
| SprinkleState *state; |
| |
| gst_init (&argc, &argv); |
| |
| loop = g_main_loop_new (NULL, TRUE); |
| |
| pipeline = gst_pipeline_new ("pipeline"); |
| |
| /* add the fixed part to the pipeline. Remember that we need a capsfilter |
| * after adder so that multiple sources are not racing to negotiate |
| * a format */ |
| adder = gst_element_factory_make ("adder", "adder"); |
| filter = gst_element_factory_make ("capsfilter", "filter"); |
| convert = gst_element_factory_make ("audioconvert", "convert"); |
| sink = gst_element_factory_make ("autoaudiosink", "sink"); |
| |
| caps = gst_caps_new_simple ("audio/x-raw", |
| "format", G_TYPE_STRING, "S16LE", |
| "channels", G_TYPE_INT, 1, "rate", G_TYPE_INT, 44100, NULL); |
| g_object_set (filter, "caps", caps, NULL); |
| gst_caps_unref (caps); |
| |
| gst_bin_add_many (GST_BIN (pipeline), adder, filter, convert, sink, NULL); |
| |
| linked = gst_element_link_many (adder, filter, convert, sink, NULL); |
| g_assert (linked); |
| |
| /* setup message handling */ |
| bus = gst_pipeline_get_bus (GST_PIPELINE (pipeline)); |
| gst_bus_add_signal_watch_full (bus, G_PRIORITY_HIGH); |
| g_signal_connect (bus, "message::error", (GCallback) message_received, |
| pipeline); |
| g_signal_connect (bus, "message::warning", (GCallback) message_received, |
| pipeline); |
| g_signal_connect (bus, "message::eos", (GCallback) eos_message_received, |
| pipeline); |
| |
| /* we set the pipeline to PLAYING, the pipeline will not yet preroll because |
| * there is no source providing data for it yet */ |
| gst_element_set_state (pipeline, GST_STATE_PLAYING); |
| |
| /* and add the function that modifies the pipeline every 100ms */ |
| state = create_state (); |
| g_timeout_add (100, (GSourceFunc) do_sprinkle, state); |
| |
| /* go to main loop */ |
| g_main_loop_run (loop); |
| |
| gst_element_set_state (pipeline, GST_STATE_NULL); |
| |
| free_state (state); |
| gst_object_unref (bus); |
| gst_object_unref (pipeline); |
| |
| return 0; |
| } |