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220 lines
6.2 KiB
C
220 lines
6.2 KiB
C
/* GStreamer
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*
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* appsrc-stream2.c: example for using appsrc in streaming mode.
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*
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* Copyright (C) 2008 Wim Taymans <wim.taymans@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <gst/gst.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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GST_DEBUG_CATEGORY (appsrc_playbin_debug);
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#define GST_CAT_DEFAULT appsrc_playbin_debug
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/*
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* an example application of using appsrc in streaming pull mode. When the
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* appsrc request data with the need-data signal, we retrieve a buffer of an
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* arbitrary size and push it to appsrc.
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*
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* This example keeps the internal buffer queue of appsrc to a minimal size,
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* only feeding data to appsrc when needed.
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*
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* This is a good example how one would deal with a live resource, such as a udp
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* socket where one would feed the most recently acquired buffer to appsrc.
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*
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* Usually one would timestamp the buffers with the running_time of the
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* pipeline or configure the appsrc to do timestamping by setting the
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* do-timestamp property to TRUE.
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*
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* Appsrc in streaming mode (the default) does not support seeking so we don't
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* have to handle any seek callbacks.
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*
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* Some formats are able to estimate the duration of the media file based on the
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* file length (mp3, mpeg,..), others report an unknown length (ogg,..).
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*/
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typedef struct _App App;
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struct _App
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{
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GstElement *playbin;
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GstElement *appsrc;
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GMainLoop *loop;
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GMappedFile *file;
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guint8 *data;
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gsize length;
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guint64 offset;
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};
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App s_app;
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#define CHUNK_SIZE 4096
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/* This method is called by the need-data signal callback, we feed data into the
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* appsrc.
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*/
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static void
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feed_data (GstElement * appsrc, guint size, App * app)
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{
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GstBuffer *buffer;
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guint len;
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GstFlowReturn ret;
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if (app->offset >= app->length) {
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/* we are EOS, send end-of-stream */
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g_signal_emit_by_name (app->appsrc, "end-of-stream", &ret);
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return;
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}
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/* read the next chunk */
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buffer = gst_buffer_new ();
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len = CHUNK_SIZE;
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if (app->offset + len > app->length)
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len = app->length - app->offset;
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gst_buffer_append_memory (buffer,
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gst_memory_new_wrapped (GST_MEMORY_FLAG_READONLY,
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app->data, app->length, app->offset, len, NULL, NULL));
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GST_DEBUG ("feed buffer %p, offset %" G_GUINT64_FORMAT "-%u", buffer,
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app->offset, len);
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g_signal_emit_by_name (app->appsrc, "push-buffer", buffer, &ret);
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gst_buffer_unref (buffer);
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app->offset += len;
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return;
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}
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/* this callback is called when playbin has constructed a source object to read
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* from. Since we provided the appsrc:// uri to playbin, this will be the
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* appsrc that we must handle. We set up a signals to push data into appsrc. */
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static void
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found_source (GObject * object, GObject * orig, GParamSpec * pspec, App * app)
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{
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/* get a handle to the appsrc */
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g_object_get (orig, pspec->name, &app->appsrc, NULL);
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GST_DEBUG ("got appsrc %p", app->appsrc);
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/* we can set the length in appsrc. This allows some elements to estimate the
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* total duration of the stream. It's a good idea to set the property when you
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* can but it's not required. */
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g_object_set (app->appsrc, "size", (gint64) app->length, NULL);
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/* configure the appsrc, we will push a buffer to appsrc when it needs more
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* data */
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g_signal_connect (app->appsrc, "need-data", G_CALLBACK (feed_data), app);
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}
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static gboolean
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bus_message (GstBus * bus, GstMessage * message, App * app)
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{
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GST_DEBUG ("got message %s",
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gst_message_type_get_name (GST_MESSAGE_TYPE (message)));
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switch (GST_MESSAGE_TYPE (message)) {
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case GST_MESSAGE_ERROR:
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g_error ("received error");
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g_main_loop_quit (app->loop);
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break;
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case GST_MESSAGE_EOS:
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g_main_loop_quit (app->loop);
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break;
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default:
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break;
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}
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return TRUE;
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}
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int
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main (int argc, char *argv[])
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{
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App *app = &s_app;
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GError *error = NULL;
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GstBus *bus;
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gst_init (&argc, &argv);
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GST_DEBUG_CATEGORY_INIT (appsrc_playbin_debug, "appsrc-playbin", 0,
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"appsrc playbin example");
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if (argc < 2) {
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g_print ("usage: %s <filename>\n", argv[0]);
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return -1;
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}
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/* try to open the file as an mmapped file */
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app->file = g_mapped_file_new (argv[1], FALSE, &error);
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if (error) {
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g_print ("failed to open file: %s\n", error->message);
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g_error_free (error);
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return -2;
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}
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/* get some vitals, this will be used to read data from the mmapped file and
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* feed it to appsrc. */
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app->length = g_mapped_file_get_length (app->file);
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app->data = (guint8 *) g_mapped_file_get_contents (app->file);
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app->offset = 0;
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/* create a mainloop to get messages */
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app->loop = g_main_loop_new (NULL, TRUE);
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app->playbin = gst_element_factory_make ("playbin", NULL);
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g_assert (app->playbin);
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bus = gst_pipeline_get_bus (GST_PIPELINE (app->playbin));
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/* add watch for messages */
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gst_bus_add_watch (bus, (GstBusFunc) bus_message, app);
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/* set to read from appsrc */
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g_object_set (app->playbin, "uri", "appsrc://", NULL);
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/* get notification when the source is created so that we get a handle to it
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* and can configure it */
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g_signal_connect (app->playbin, "deep-notify::source",
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(GCallback) found_source, app);
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/* go to playing and wait in a mainloop. */
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gst_element_set_state (app->playbin, GST_STATE_PLAYING);
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/* this mainloop is stopped when we receive an error or EOS */
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g_main_loop_run (app->loop);
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GST_DEBUG ("stopping");
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gst_element_set_state (app->playbin, GST_STATE_NULL);
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/* free the file */
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g_mapped_file_unref (app->file);
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gst_object_unref (bus);
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g_main_loop_unref (app->loop);
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return 0;
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}
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