/* GStreamer

 *

 * appsrc-stream.c: example for using appsrc in streaming 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 streaming push mode. We simply push

 * buffers into appsrc. The size of the buffers we push can be any size we

 * choose.

 *

 * This example is very close to how one would deal with a streaming webserver

 * that does not support range requests or does not report the total file size.

 *

 * Some optimisations are done so that we don't push too much data. We connect

 * to the need-data and enough-data signals to start/stop sending buffers.

 *

 * Appsrc in streaming mode (the default) does not support seeking so we don't

 * have to handle any seek callbacks.

 *

 * Some formats are able to estimate the duration of the media file based on the

 * file length (mp3, mpeg,..), others report an unknown length (ogg,..).

 */

typedef struct _App App;

struct _App

{

  GstElement *playbin;

  GstElement *appsrc;

  GMainLoop *loop;

  guint sourceid;

  GMappedFile *file;

  guint8 *data;

  gsize length;

  guint64 offset;

};

App s_app;

#define CHUNK_SIZE  4096

/* This method is called by the idle GSource in the mainloop. We feed CHUNK_SIZE

 * bytes into appsrc.

 * The ide handler is added to the mainloop when appsrc requests us to start

 * sending data (need-data signal) and is removed when appsrc has enough data

 * (enough-data signal).

 */

static gboolean

read_data (App * app)

{

  GstBuffer *buffer;

  guint len;

  GstFlowReturn ret;

  buffer = gst_buffer_new ();

  if (app->offset >= app->length) {

    /* we are EOS, send end-of-stream and remove the source */

    g_signal_emit_by_name (app->appsrc, "end-of-stream", &ret);

    return FALSE;

  }

  /* read the next chunk */

  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);

  gst_buffer_unref (buffer);

  if (ret != GST_FLOW_OK) {

    /* some error, stop sending data */

    return FALSE;

  }

  app->offset += len;

  return TRUE;

}

/* This signal callback is called when appsrc needs data, we add an idle handler

 * to the mainloop to start pushing data into the appsrc */

static void

start_feed (GstElement * playbin, guint size, App * app)

{

  if (app->sourceid == 0) {

    GST_DEBUG ("start feeding");

    app->sourceid = g_idle_add ((GSourceFunc) read_data, app);

  }

}

/* This callback is called when appsrc has enough data and we can stop sending.

 * We remove the idle handler from the mainloop */

static void

stop_feed (GstElement * playbin, App * app)

{

  if (app->sourceid != 0) {

    GST_DEBUG ("stop feeding");

    g_source_remove (app->sourceid);

    app->sourceid = 0;

  }

}

/* 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 start and stop pushing

 * data into appsrc */

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", (gint64) app->length, NULL);

  /* configure the appsrc, we will push data into the appsrc from the

   * mainloop. */

  g_signal_connect (app->appsrc, "need-data", G_CALLBACK (start_feed), app);

  g_signal_connect (app->appsrc, "enough-data", G_CALLBACK (stop_feed), 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 and to handle the idle handler that will

   * feed data to appsrc. */

  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;

}