examples/app/: Added 3 more example application for using appsrc in random-access mode, pull-mode streaming and pull ...

Original commit message from CVS:
* examples/app/Makefile.am:
* examples/app/appsrc-ra.c: (feed_data), (seek_data),
(found_source), (bus_message), (main):
* examples/app/appsrc-seekable.c: (feed_data), (seek_data),
(found_source), (bus_message), (main):
* examples/app/appsrc-stream2.c: (feed_data), (found_source),
(bus_message), (main):
Added 3 more example application for using appsrc in random-access mode,
pull-mode streaming and pull mode seekable.
* gst-libs/gst/app/gstappsrc.c: (gst_app_src_class_init),
(gst_app_src_start), (gst_app_src_do_get_size),
(gst_app_src_create):
* gst-libs/gst/app/gstappsrc.h:
Make stream-type property writable.
Unset flushing when starting so that we reuse appsrc.
Inform basesrc about the configured size.
Emit seek-data signal when we are going to a different offset in
random-access mode.

1 files changed, 228 insertions, 0 deletions

diff --git a/tests/examples/app/appsrc-seekable.c b/tests/examples/app/appsrc-seekable.c
new file mode 100644
index 000000000..12af93d16
--- /dev/null
+++ b/tests/examples/app/appsrc-seekable.c
@@ -0,0 +1,228 @@
+/* GStreamer
+ *
+ * appsrc-seekable.c: example for using appsrc in seekable mode.
+ *
+ * Copyright (C) 2008 Wim Taymans <wim.taymans@gmail.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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+GST_DEBUG_CATEGORY (appsrc_playbin_debug);
+#define GST_CAT_DEFAULT appsrc_playbin_debug
+
+/**
+ * an example application of using appsrc in seekable mode. When the
+ * appsrc requests data with the need-data signal, we retrieve a buffer and
+ * push it to appsrc. We can also use the method as demonstrated in
+ * appsrc-stream.c, ie. pushing buffers when we can.
+ *
+ * This is a good example how one would deal with a remote http server that
+ * supports range requests.
+ *
+ * Appsrc in seekable mode needs seeking support and we must thus connect
+ * to the seek signal to perform any seeks when requested.
+ *
+ * In seekable mode we should set the size of the source material.
+ */
+typedef struct _App App;
+
+struct _App
+{
+  GstElement *playbin;
+  GstElement *appsrc;
+
+  GMainLoop *loop;
+
+  GMappedFile *file;
+  guint8 *data;
+  gsize length;
+  guint64 offset;
+};
+
+App s_app;
+
+#define CHUNK_SIZE  4096
+
+/* This method is called by the need-data signal callback, we feed data into the
+ * appsrc with an arbitrary size.
+ */
+static void
+feed_data (GstElement * appsrc, guint size, App * app)
+{
+  GstBuffer *buffer;
+  guint len;
+  GstFlowReturn ret;
+
+  buffer = gst_buffer_new ();
+
+  if (app->offset >= app->length) {
+    /* we are EOS, send end-of-stream */
+    g_signal_emit_by_name (app->appsrc, "end-of-stream", &ret);
+    return;
+  }
+
+  /* read any amount of data, we are allowed to return less if we are EOS */
+  len = CHUNK_SIZE;
+  if (app->offset + len > app->length)
+    len = app->length - app->offset;
+
+  GST_BUFFER_DATA (buffer) = app->data + app->offset;
+  GST_BUFFER_SIZE (buffer) = len;
+
+  GST_DEBUG ("feed buffer %p, offset %" G_GUINT64_FORMAT "-%u", buffer,
+      app->offset, len);
+  g_signal_emit_by_name (app->appsrc, "push-buffer", buffer, &ret);
+
+  app->offset += len;
+
+  return;
+}
+
+/* called when appsrc wants us to return data from a new position with the next
+ * call to push-buffer. */
+static gboolean
+seek_data (GstElement * appsrc, guint64 position, App * app)
+{
+  GST_DEBUG ("seek to offset %" G_GUINT64_FORMAT, position);
+  app->offset = position;
+
+  return TRUE;
+}
+
+/* this callback is called when playbin2 has constructed a source object to read
+ * from. Since we provided the appsrc:// uri to playbin2, this will be the
+ * appsrc that we must handle. We set up some signals to push data into appsrc
+ * and one to perform a seek. */
+static void
+found_source (GObject * object, GObject * orig, GParamSpec * pspec, App * app)
+{
+  /* get a handle to the appsrc */
+  g_object_get (orig, pspec->name, &app->appsrc, NULL);
+
+  GST_DEBUG ("got appsrc %p", app->appsrc);
+
+  /* we can set the length in appsrc. This allows some elements to estimate the
+   * total duration of the stream. It's a good idea to set the property when you
+   * can but it's not required. */
+  g_object_set (app->appsrc, "size", app->length, NULL);
+  /* we are seekable in push mode, this means that the element usually pushes
+   * out buffers of an undefined size and that seeks happen only occasionally
+   * and only by request of the user. */
+  g_object_set (app->appsrc, "stream-type", 1, NULL);
+
+  /* configure the appsrc, we will push a buffer to appsrc when it needs more
+   * data */
+  g_signal_connect (app->appsrc, "need-data", G_CALLBACK (feed_data), app);
+  g_signal_connect (app->appsrc, "seek-data", G_CALLBACK (seek_data), app);
+}
+
+static gboolean
+bus_message (GstBus * bus, GstMessage * message, App * app)
+{
+  GST_DEBUG ("got message %s",
+      gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
+
+  switch (GST_MESSAGE_TYPE (message)) {
+    case GST_MESSAGE_ERROR:
+      g_error ("received error");
+      g_main_loop_quit (app->loop);
+      break;
+    case GST_MESSAGE_EOS:
+      g_main_loop_quit (app->loop);
+      break;
+    default:
+      break;
+  }
+  return TRUE;
+}
+
+int
+main (int argc, char *argv[])
+{
+  App *app = &s_app;
+  GError *error = NULL;
+  GstBus *bus;
+
+  gst_init (&argc, &argv);
+
+  GST_DEBUG_CATEGORY_INIT (appsrc_playbin_debug, "appsrc-playbin", 0,
+      "appsrc playbin example");
+
+  if (argc < 2) {
+    g_print ("usage: %s <filename>\n", argv[0]);
+    return -1;
+  }
+
+  /* try to open the file as an mmapped file */
+  app->file = g_mapped_file_new (argv[1], FALSE, &error);
+  if (error) {
+    g_print ("failed to open file: %s\n", error->message);
+    g_error_free (error);
+    return -2;
+  }
+  /* get some vitals, this will be used to read data from the mmapped file and
+   * feed it to appsrc. */
+  app->length = g_mapped_file_get_length (app->file);
+  app->data = (guint8 *) g_mapped_file_get_contents (app->file);
+  app->offset = 0;
+
+  /* create a mainloop to get messages */
+  app->loop = g_main_loop_new (NULL, TRUE);
+
+  app->playbin = gst_element_factory_make ("playbin2", NULL);
+  g_assert (app->playbin);
+
+  bus = gst_pipeline_get_bus (GST_PIPELINE (app->playbin));
+
+  /* add watch for messages */
+  gst_bus_add_watch (bus, (GstBusFunc) bus_message, app);
+
+  /* set to read from appsrc */
+  g_object_set (app->playbin, "uri", "appsrc://", NULL);
+
+  /* get notification when the source is created so that we get a handle to it
+   * and can configure it */
+  g_signal_connect (app->playbin, "deep-notify::source",
+      (GCallback) found_source, app);
+
+  /* go to playing and wait in a mainloop. */
+  gst_element_set_state (app->playbin, GST_STATE_PLAYING);
+
+  /* this mainloop is stopped when we receive an error or EOS */
+  g_main_loop_run (app->loop);
+
+  GST_DEBUG ("stopping");
+
+  gst_element_set_state (app->playbin, GST_STATE_NULL);
+
+  /* free the file */
+  g_mapped_file_free (app->file);
+
+  gst_object_unref (bus);
+  g_main_loop_unref (app->loop);
+
+  return 0;
+}