gstreamer/examples/tutorials/basic-tutorial-9.c

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6 KiB
C

#include <string.h>
#include <gst/gst.h>
#include <gst/pbutils/pbutils.h>
/* Structure to contain all our information, so we can pass it around */
typedef struct _CustomData {
GstDiscoverer *discoverer;
GMainLoop *loop;
} CustomData;
/* Print a tag in a human-readable format (name: value) */
static void print_tag_foreach (const GstTagList *tags, const gchar *tag, gpointer user_data) {
GValue val = { 0, };
gchar *str;
gint depth = GPOINTER_TO_INT (user_data);
gst_tag_list_copy_value (&val, tags, tag);
if (G_VALUE_HOLDS_STRING (&val))
str = g_value_dup_string (&val);
else
str = gst_value_serialize (&val);
g_print ("%*s%s: %s\n", 2 * depth, " ", gst_tag_get_nick (tag), str);
g_free (str);
g_value_unset (&val);
}
/* Print information regarding a stream */
static void print_stream_info (GstDiscovererStreamInfo *info, gint depth) {
gchar *desc = NULL;
GstCaps *caps;
const GstTagList *tags;
caps = gst_discoverer_stream_info_get_caps (info);
if (caps) {
if (gst_caps_is_fixed (caps))
desc = gst_pb_utils_get_codec_description (caps);
else
desc = gst_caps_to_string (caps);
gst_caps_unref (caps);
}
g_print ("%*s%s: %s\n", 2 * depth, " ", gst_discoverer_stream_info_get_stream_type_nick (info), (desc ? desc : ""));
if (desc) {
g_free (desc);
desc = NULL;
}
tags = gst_discoverer_stream_info_get_tags (info);
if (tags) {
g_print ("%*sTags:\n", 2 * (depth + 1), " ");
gst_tag_list_foreach (tags, print_tag_foreach, GINT_TO_POINTER (depth + 2));
}
}
/* Print information regarding a stream and its substreams, if any */
static void print_topology (GstDiscovererStreamInfo *info, gint depth) {
GstDiscovererStreamInfo *next;
if (!info)
return;
print_stream_info (info, depth);
next = gst_discoverer_stream_info_get_next (info);
if (next) {
print_topology (next, depth + 1);
gst_discoverer_stream_info_unref (next);
} else if (GST_IS_DISCOVERER_CONTAINER_INFO (info)) {
GList *tmp, *streams;
streams = gst_discoverer_container_info_get_streams (GST_DISCOVERER_CONTAINER_INFO (info));
for (tmp = streams; tmp; tmp = tmp->next) {
GstDiscovererStreamInfo *tmpinf = (GstDiscovererStreamInfo *) tmp->data;
print_topology (tmpinf, depth + 1);
}
gst_discoverer_stream_info_list_free (streams);
}
}
/* This function is called every time the discoverer has information regarding
* one of the URIs we provided.*/
static void on_discovered_cb (GstDiscoverer *discoverer, GstDiscovererInfo *info, GError *err, CustomData *data) {
GstDiscovererResult result;
const gchar *uri;
const GstTagList *tags;
GstDiscovererStreamInfo *sinfo;
uri = gst_discoverer_info_get_uri (info);
result = gst_discoverer_info_get_result (info);
switch (result) {
case GST_DISCOVERER_URI_INVALID:
g_print ("Invalid URI '%s'\n", uri);
break;
case GST_DISCOVERER_ERROR:
g_print ("Discoverer error: %s\n", err->message);
break;
case GST_DISCOVERER_TIMEOUT:
g_print ("Timeout\n");
break;
case GST_DISCOVERER_BUSY:
g_print ("Busy\n");
break;
case GST_DISCOVERER_MISSING_PLUGINS:{
const GstStructure *s;
gchar *str;
s = gst_discoverer_info_get_misc (info);
str = gst_structure_to_string (s);
g_print ("Missing plugins: %s\n", str);
g_free (str);
break;
}
case GST_DISCOVERER_OK:
g_print ("Discovered '%s'\n", uri);
break;
}
if (result != GST_DISCOVERER_OK) {
g_printerr ("This URI cannot be played\n");
return;
}
/* If we got no error, show the retrieved information */
g_print ("\nDuration: %" GST_TIME_FORMAT "\n", GST_TIME_ARGS (gst_discoverer_info_get_duration (info)));
tags = gst_discoverer_info_get_tags (info);
if (tags) {
g_print ("Tags:\n");
gst_tag_list_foreach (tags, print_tag_foreach, GINT_TO_POINTER (1));
}
g_print ("Seekable: %s\n", (gst_discoverer_info_get_seekable (info) ? "yes" : "no"));
g_print ("\n");
sinfo = gst_discoverer_info_get_stream_info (info);
if (!sinfo)
return;
g_print ("Stream information:\n");
print_topology (sinfo, 1);
gst_discoverer_stream_info_unref (sinfo);
g_print ("\n");
}
/* This function is called when the discoverer has finished examining
* all the URIs we provided.*/
static void on_finished_cb (GstDiscoverer *discoverer, CustomData *data) {
g_print ("Finished discovering\n");
g_main_loop_quit (data->loop);
}
int main (int argc, char **argv) {
CustomData data;
GError *err = NULL;
gchar *uri = "https://www.freedesktop.org/software/gstreamer-sdk/data/media/sintel_trailer-480p.webm";
/* if a URI was provided, use it instead of the default one */
if (argc > 1) {
uri = argv[1];
}
/* Initialize cumstom data structure */
memset (&data, 0, sizeof (data));
/* Initialize GStreamer */
gst_init (&argc, &argv);
g_print ("Discovering '%s'\n", uri);
/* Instantiate the Discoverer */
data.discoverer = gst_discoverer_new (5 * GST_SECOND, &err);
if (!data.discoverer) {
g_print ("Error creating discoverer instance: %s\n", err->message);
g_clear_error (&err);
return -1;
}
/* Connect to the interesting signals */
g_signal_connect (data.discoverer, "discovered", G_CALLBACK (on_discovered_cb), &data);
g_signal_connect (data.discoverer, "finished", G_CALLBACK (on_finished_cb), &data);
/* Start the discoverer process (nothing to do yet) */
gst_discoverer_start (data.discoverer);
/* Add a request to process asynchronously the URI passed through the command line */
if (!gst_discoverer_discover_uri_async (data.discoverer, uri)) {
g_print ("Failed to start discovering URI '%s'\n", uri);
g_object_unref (data.discoverer);
return -1;
}
/* Create a GLib Main Loop and set it to run, so we can wait for the signals */
data.loop = g_main_loop_new (NULL, FALSE);
g_main_loop_run (data.loop);
/* Stop the discoverer process */
gst_discoverer_stop (data.discoverer);
/* Free resources */
g_object_unref (data.discoverer);
g_main_loop_unref (data.loop);
return 0;
}