gstreamer/subprojects/gst-docs/examples/tutorials/playback-tutorial-2.c

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#include <stdio.h>
#include <gst/gst.h>
/* Structure to contain all our information, so we can pass it around */
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typedef struct _CustomData
{
GstElement *playbin; /* Our one and only element */
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gint n_video; /* Number of embedded video streams */
gint n_audio; /* Number of embedded audio streams */
gint n_text; /* Number of embedded subtitle streams */
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gint current_video; /* Currently playing video stream */
gint current_audio; /* Currently playing audio stream */
gint current_text; /* Currently playing subtitle stream */
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GMainLoop *main_loop; /* GLib's Main Loop */
} CustomData;
/* playbin flags */
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typedef enum
{
GST_PLAY_FLAG_VIDEO = (1 << 0), /* We want video output */
GST_PLAY_FLAG_AUDIO = (1 << 1), /* We want audio output */
GST_PLAY_FLAG_TEXT = (1 << 2) /* We want subtitle output */
} GstPlayFlags;
/* Forward definition for the message and keyboard processing functions */
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static gboolean handle_message (GstBus * bus, GstMessage * msg,
CustomData * data);
static gboolean handle_keyboard (GIOChannel * source, GIOCondition cond,
CustomData * data);
int
main (int argc, char *argv[])
{
CustomData data;
GstBus *bus;
GstStateChangeReturn ret;
gint flags;
GIOChannel *io_stdin;
/* Initialize GStreamer */
gst_init (&argc, &argv);
/* Create the elements */
data.playbin = gst_element_factory_make ("playbin", "playbin");
if (!data.playbin) {
g_printerr ("Not all elements could be created.\n");
return -1;
}
/* Set the URI to play */
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g_object_set (data.playbin, "uri",
"https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.ogv",
NULL);
/* Set the subtitle URI to play and some font description */
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g_object_set (data.playbin, "suburi",
"https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer_gr.srt",
NULL);
g_object_set (data.playbin, "subtitle-font-desc", "Sans, 18", NULL);
/* Set flags to show Audio, Video and Subtitles */
g_object_get (data.playbin, "flags", &flags, NULL);
flags |= GST_PLAY_FLAG_VIDEO | GST_PLAY_FLAG_AUDIO | GST_PLAY_FLAG_TEXT;
g_object_set (data.playbin, "flags", flags, NULL);
/* Add a bus watch, so we get notified when a message arrives */
bus = gst_element_get_bus (data.playbin);
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gst_bus_add_watch (bus, (GstBusFunc) handle_message, &data);
/* Add a keyboard watch so we get notified of keystrokes */
#ifdef G_OS_WIN32
io_stdin = g_io_channel_win32_new_fd (fileno (stdin));
#else
io_stdin = g_io_channel_unix_new (fileno (stdin));
#endif
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g_io_add_watch (io_stdin, G_IO_IN, (GIOFunc) handle_keyboard, &data);
/* Start playing */
ret = gst_element_set_state (data.playbin, GST_STATE_PLAYING);
if (ret == GST_STATE_CHANGE_FAILURE) {
g_printerr ("Unable to set the pipeline to the playing state.\n");
gst_object_unref (data.playbin);
return -1;
}
/* Create a GLib Main Loop and set it to run */
data.main_loop = g_main_loop_new (NULL, FALSE);
g_main_loop_run (data.main_loop);
/* Free resources */
g_main_loop_unref (data.main_loop);
g_io_channel_unref (io_stdin);
gst_object_unref (bus);
gst_element_set_state (data.playbin, GST_STATE_NULL);
gst_object_unref (data.playbin);
return 0;
}
/* Extract some metadata from the streams and print it on the screen */
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static void
analyze_streams (CustomData * data)
{
gint i;
GstTagList *tags;
gchar *str;
guint rate;
/* Read some properties */
g_object_get (data->playbin, "n-video", &data->n_video, NULL);
g_object_get (data->playbin, "n-audio", &data->n_audio, NULL);
g_object_get (data->playbin, "n-text", &data->n_text, NULL);
g_print ("%d video stream(s), %d audio stream(s), %d text stream(s)\n",
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data->n_video, data->n_audio, data->n_text);
g_print ("\n");
for (i = 0; i < data->n_video; i++) {
tags = NULL;
/* Retrieve the stream's video tags */
g_signal_emit_by_name (data->playbin, "get-video-tags", i, &tags);
if (tags) {
g_print ("video stream %d:\n", i);
gst_tag_list_get_string (tags, GST_TAG_VIDEO_CODEC, &str);
g_print (" codec: %s\n", str ? str : "unknown");
g_free (str);
gst_tag_list_free (tags);
}
}
g_print ("\n");
for (i = 0; i < data->n_audio; i++) {
tags = NULL;
/* Retrieve the stream's audio tags */
g_signal_emit_by_name (data->playbin, "get-audio-tags", i, &tags);
if (tags) {
g_print ("audio stream %d:\n", i);
if (gst_tag_list_get_string (tags, GST_TAG_AUDIO_CODEC, &str)) {
g_print (" codec: %s\n", str);
g_free (str);
}
if (gst_tag_list_get_string (tags, GST_TAG_LANGUAGE_CODE, &str)) {
g_print (" language: %s\n", str);
g_free (str);
}
if (gst_tag_list_get_uint (tags, GST_TAG_BITRATE, &rate)) {
g_print (" bitrate: %d\n", rate);
}
gst_tag_list_free (tags);
}
}
g_print ("\n");
for (i = 0; i < data->n_text; i++) {
tags = NULL;
/* Retrieve the stream's subtitle tags */
g_print ("subtitle stream %d:\n", i);
g_signal_emit_by_name (data->playbin, "get-text-tags", i, &tags);
if (tags) {
if (gst_tag_list_get_string (tags, GST_TAG_LANGUAGE_CODE, &str)) {
g_print (" language: %s\n", str);
g_free (str);
}
gst_tag_list_free (tags);
} else {
g_print (" no tags found\n");
}
}
g_object_get (data->playbin, "current-video", &data->current_video, NULL);
g_object_get (data->playbin, "current-audio", &data->current_audio, NULL);
g_object_get (data->playbin, "current-text", &data->current_text, NULL);
g_print ("\n");
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g_print
("Currently playing video stream %d, audio stream %d and subtitle stream %d\n",
data->current_video, data->current_audio, data->current_text);
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g_print
("Type any number and hit ENTER to select a different subtitle stream\n");
}
/* Process messages from GStreamer */
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static gboolean
handle_message (GstBus * bus, GstMessage * msg, CustomData * data)
{
GError *err;
gchar *debug_info;
switch (GST_MESSAGE_TYPE (msg)) {
case GST_MESSAGE_ERROR:
gst_message_parse_error (msg, &err, &debug_info);
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g_printerr ("Error received from element %s: %s\n",
GST_OBJECT_NAME (msg->src), err->message);
g_printerr ("Debugging information: %s\n",
debug_info ? debug_info : "none");
g_clear_error (&err);
g_free (debug_info);
g_main_loop_quit (data->main_loop);
break;
case GST_MESSAGE_EOS:
g_print ("End-Of-Stream reached.\n");
g_main_loop_quit (data->main_loop);
break;
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case GST_MESSAGE_STATE_CHANGED:{
GstState old_state, new_state, pending_state;
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gst_message_parse_state_changed (msg, &old_state, &new_state,
&pending_state);
if (GST_MESSAGE_SRC (msg) == GST_OBJECT (data->playbin)) {
if (new_state == GST_STATE_PLAYING) {
/* Once we are in the playing state, analyze the streams */
analyze_streams (data);
}
}
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}
break;
default:
break;
}
/* We want to keep receiving messages */
return TRUE;
}
/* Process keyboard input */
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static gboolean
handle_keyboard (GIOChannel * source, GIOCondition cond, CustomData * data)
{
gchar *str = NULL;
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if (g_io_channel_read_line (source, &str, NULL, NULL,
NULL) == G_IO_STATUS_NORMAL) {
int index = g_ascii_strtoull (str, NULL, 0);
if (index < 0 || index >= data->n_text) {
g_printerr ("Index out of bounds\n");
} else {
/* If the input was a valid subtitle stream index, set the current subtitle stream */
g_print ("Setting current subtitle stream to %d\n", index);
g_object_set (data->playbin, "current-text", index, NULL);
}
}
g_free (str);
return TRUE;
}