/* GStreamer * * appsrc-stream2.c: example for using appsrc in streaming mode. * * Copyright (C) 2008 Wim Taymans * * 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. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include GST_DEBUG_CATEGORY (appsrc_playbin_debug); #define GST_CAT_DEFAULT appsrc_playbin_debug /* * an example application of using appsrc in streaming pull mode. When the * appsrc request data with the need-data signal, we retrieve a buffer of an * arbitrary size and push it to appsrc. * * This example keeps the internal buffer queue of appsrc to a minimal size, * only feeding data to appsrc when needed. * * This is a good example how one would deal with a live resource, such as a udp * socket where one would feed the most recently acquired buffer to appsrc. * * Usually one would timestamp the buffers with the running_time of the * pipeline or configure the appsrc to do timestamping by setting the * do-timestamp property to TRUE. * * 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; 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. */ static void feed_data (GstElement * appsrc, guint size, App * app) { GstBuffer *buffer; guint len; GstFlowReturn ret; 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 the next chunk */ buffer = gst_buffer_new (); len = CHUNK_SIZE; if (app->offset + len > app->length) len = app->length - app->offset; gst_buffer_append_memory (buffer, gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY, app->data, app->length, app->offset, len, NULL, NULL)); 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); app->offset += len; return; } /* this callback is called when playbin has constructed a source object to read * from. Since we provided the appsrc:// uri to playbin, this will be the * appsrc that we must handle. We set up a signals to push 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 a buffer to appsrc when it needs more * data */ g_signal_connect (app->appsrc, "need-data", G_CALLBACK (feed_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 \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 ("playbin", 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_unref (app->file); gst_object_unref (bus); g_main_loop_unref (app->loop); return 0; }