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gstreamer/subprojects/gst-plugins-bad/gst/switchbin/gstswitchbin.c

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/* switchbin
* Copyright (C) 2016 Carlos Rafael Giani
*
* gstswitchbin.c: Element for switching between paths based on input caps
*
* 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.
*/
/**
* SECTION:element-switchbin
* @title: switchbin
*
* switchbin is a helper element which chooses between a set of
* processing chains (paths) based on input caps, and changes if new caps
* arrive. Paths are child objects, which are accessed by the
* #GstChildProxy interface.
*
* Whenever new input caps are encountered at the switchbin's sinkpad,
* the * first path with matching caps is picked. The paths are looked at
* in order: path \#0's caps are looked at first, checked against the new
* input caps with gst_caps_can_intersect(), and if its return value
* is TRUE, path \#0 is picked. Otherwise, path \#1's caps are looked at etc.
* If no path matches, an error is reported.
*
* <refsect2>
* <title>Example launch line</title>
*
* In this example, if the data is raw PCM audio with 44.1 kHz, a volume
* element is used for reducing the audio volume to 10%. Otherwise, it is
* just passed through. So, a 44.1 kHz MP3 will sound quiet, a 48 kHz MP3
* will be at full volume.
*
* |[
* gst-launch-1.0 uridecodebin uri=<URI> ! switchbin num-paths=2 \
* path0::element="audioconvert ! volume volume=0.1" path0::caps="audio/x-raw, rate=44100" \
* path1::element="identity" path1::caps="ANY" ! \
* autoaudiosink
* ]|
*
* This example's path \#1 is a fallback "catch-all" path. Its caps are "ANY" caps,
* so any input caps will match against this. A catch-all path with an identity element
* is useful for cases where certain kinds of processing should only be done for specific
* formats, like the example above (it applies volume only to 44.1 kHz PCM audio).
* </refsect2>
*
*/
#include <string.h>
#include <stdio.h>
#include "gstswitchbin.h"
GST_DEBUG_CATEGORY (switch_bin_debug);
#define GST_CAT_DEFAULT switch_bin_debug
enum
{
PROP_0,
PROP_NUM_PATHS,
PROP_CURRENT_PATH,
PROP_LAST
};
#define DEFAULT_NUM_PATHS 0
GParamSpec *switchbin_props[PROP_LAST];
#define PATH_LOCK(obj) g_mutex_lock(&(GST_SWITCH_BIN_CAST (obj)->path_mutex))
#define PATH_UNLOCK(obj) g_mutex_unlock(&(GST_SWITCH_BIN_CAST (obj)->path_mutex))
#define PATH_UNLOCK_AND_CHECK(obj) gst_switch_bin_unlock_paths_and_notify(GST_SWITCH_BIN_CAST (obj));
static GstStaticPadTemplate static_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static GstStaticPadTemplate static_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static void gst_switch_bin_child_proxy_iface_init (gpointer iface,
gpointer iface_data);
static GObject *gst_switch_bin_child_proxy_get_child_by_index (GstChildProxy *
child_proxy, guint index);
static guint gst_switch_bin_child_proxy_get_children_count (GstChildProxy *
child_proxy);
G_DEFINE_TYPE_WITH_CODE (GstSwitchBin,
gst_switch_bin,
GST_TYPE_BIN,
G_IMPLEMENT_INTERFACE (GST_TYPE_CHILD_PROXY,
gst_switch_bin_child_proxy_iface_init)
);
GST_ELEMENT_REGISTER_DEFINE (switchbin, "switchbin", GST_RANK_NONE,
gst_switch_bin_get_type ());
static void gst_switch_bin_unlock_paths_and_notify (GstSwitchBin * switchbin);
static void gst_switch_bin_dispose (GObject * object);
static void gst_switch_bin_finalize (GObject * object);
static void gst_switch_bin_set_property (GObject * object, guint prop_id,
GValue const *value, GParamSpec * pspec);
static void gst_switch_bin_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec);
static gboolean gst_switch_bin_sink_event (GstPad * pad,
GstObject * parent, GstEvent * event);
static gboolean gst_switch_bin_sink_query (GstPad * pad,
GstObject * parent, GstQuery * query);
static gboolean gst_switch_bin_src_query (GstPad * pad, GstObject * parent,
GstQuery * query);
static gboolean gst_switch_bin_set_num_paths (GstSwitchBin * switch_bin,
guint new_num_paths);
static gboolean gst_switch_bin_select_path_for_caps (GstSwitchBin *
switch_bin, GstCaps * caps);
static gboolean gst_switch_bin_switch_to_path (GstSwitchBin * switch_bin,
GstSwitchBinPath * switch_bin_path);
static GstSwitchBinPath *gst_switch_bin_find_matching_path (GstSwitchBin *
switch_bin, GstCaps const *caps);
static void gst_switch_bin_set_sinkpad_block (GstSwitchBin * switch_bin,
gboolean do_block);
static GstPadProbeReturn gst_switch_bin_blocking_pad_probe (GstPad * pad,
GstPadProbeInfo * info, gpointer user_data);
static GstCaps *gst_switch_bin_get_allowed_caps (GstSwitchBin * switch_bin,
GstPad * switch_bin_pad, gchar const *pad_name, GstCaps * filter);
static gboolean gst_switch_bin_are_caps_acceptable (GstSwitchBin *
switch_bin, GstCaps const *caps);
static void
gst_switch_bin_unlock_paths_and_notify (GstSwitchBin * switchbin)
{
gboolean do_notify = switchbin->path_changed;
switchbin->path_changed = FALSE;
PATH_UNLOCK (switchbin);
if (do_notify)
g_object_notify_by_pspec (G_OBJECT (switchbin),
switchbin_props[PROP_CURRENT_PATH]);
}
static void
gst_switch_bin_child_proxy_iface_init (gpointer iface,
G_GNUC_UNUSED gpointer iface_data)
{
GstChildProxyInterface *child_proxy_iface = iface;
child_proxy_iface->get_child_by_index =
GST_DEBUG_FUNCPTR (gst_switch_bin_child_proxy_get_child_by_index);
child_proxy_iface->get_children_count =
GST_DEBUG_FUNCPTR (gst_switch_bin_child_proxy_get_children_count);
}
static GObject *
gst_switch_bin_child_proxy_get_child_by_index (GstChildProxy * child_proxy,
guint index)
{
GObject *result;
GstSwitchBin *switch_bin = GST_SWITCH_BIN (child_proxy);
PATH_LOCK (switch_bin);
if (G_UNLIKELY (index >= switch_bin->num_paths))
result = NULL;
else
result = g_object_ref (G_OBJECT (switch_bin->paths[index]));
PATH_UNLOCK (switch_bin);
return result;
}
static guint
gst_switch_bin_child_proxy_get_children_count (GstChildProxy * child_proxy)
{
guint result;
GstSwitchBin *switch_bin = GST_SWITCH_BIN (child_proxy);
PATH_LOCK (switch_bin);
result = switch_bin->num_paths;
PATH_UNLOCK (switch_bin);
return result;
}
static void
gst_switch_bin_class_init (GstSwitchBinClass * klass)
{
GObjectClass *object_class;
GstElementClass *element_class;
GST_DEBUG_CATEGORY_INIT (switch_bin_debug, "switchbin", 0, "switch bin");
object_class = G_OBJECT_CLASS (klass);
element_class = GST_ELEMENT_CLASS (klass);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&static_sink_template));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&static_src_template));
object_class->dispose = GST_DEBUG_FUNCPTR (gst_switch_bin_dispose);
object_class->finalize = GST_DEBUG_FUNCPTR (gst_switch_bin_finalize);
object_class->set_property = GST_DEBUG_FUNCPTR (gst_switch_bin_set_property);
object_class->get_property = GST_DEBUG_FUNCPTR (gst_switch_bin_get_property);
/**
* GstSwitchBin:num-paths
*
* Configure how many paths the switchbin will be choosing between. Attempting
* to configure a path outside the range 0..(n-1) will fail. Reducing the
* number of paths will release any paths outside the new range, which might
* trigger activation of a new path by re-assessing the current caps.
*/
switchbin_props[PROP_NUM_PATHS] = g_param_spec_uint ("num-paths",
"Number of paths", "Number of paths", 0, G_MAXUINT - 1,
DEFAULT_NUM_PATHS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS);
g_object_class_install_property (object_class,
PROP_NUM_PATHS, switchbin_props[PROP_NUM_PATHS]);
/**
* GstSwitchBin:current-path
*
* Returns the currently selected path number. If there is no current
* path (due to no caps, or unsupported caps), the value is #G_MAXUINT. Read-only.
*/
switchbin_props[PROP_CURRENT_PATH] =
g_param_spec_uint ("current-path", "Current Path",
"Currently selected path", 0, G_MAXUINT,
0, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS);
g_object_class_install_property (object_class,
PROP_CURRENT_PATH, switchbin_props[PROP_CURRENT_PATH]);
gst_element_class_set_static_metadata (element_class,
"switchbin",
"Generic/Bin",
"Switch between sub-pipelines (paths) based on input caps",
"Carlos Rafael Giani <dv@pseudoterminal.org>");
}
static void
gst_switch_bin_init (GstSwitchBin * switch_bin)
{
GstPad *pad;
switch_bin->num_paths = DEFAULT_NUM_PATHS;
switch_bin->paths = NULL;
switch_bin->current_path = NULL;
switch_bin->last_stream_start = NULL;
switch_bin->blocking_probe_id = 0;
switch_bin->drop_probe_id = 0;
switch_bin->last_caps = NULL;
switch_bin->sinkpad = gst_ghost_pad_new_no_target_from_template ("sink",
gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (switch_bin),
"sink")
);
gst_element_add_pad (GST_ELEMENT (switch_bin), switch_bin->sinkpad);
switch_bin->srcpad = gst_ghost_pad_new_no_target_from_template ("src",
gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (switch_bin),
"src")
);
gst_element_add_pad (GST_ELEMENT (switch_bin), switch_bin->srcpad);
gst_pad_set_event_function (switch_bin->sinkpad, gst_switch_bin_sink_event);
gst_pad_set_query_function (switch_bin->sinkpad, gst_switch_bin_sink_query);
gst_pad_set_query_function (switch_bin->srcpad, gst_switch_bin_src_query);
switch_bin->input_identity =
gst_element_factory_make ("identity", "input-identity");
gst_bin_add (GST_BIN (switch_bin), switch_bin->input_identity);
pad = gst_element_get_static_pad (switch_bin->input_identity, "sink");
gst_ghost_pad_set_target (GST_GHOST_PAD (switch_bin->sinkpad), pad);
gst_object_unref (GST_OBJECT (pad));
}
static void
gst_switch_bin_dispose (GObject * object)
{
GstSwitchBin *switch_bin = GST_SWITCH_BIN (object);
guint i;
/* Chaining up will release all children of the bin,
* invalidating any pointer to elements in the paths, so make sure
* and clear those first */
PATH_LOCK (switch_bin);
for (i = 0; i < switch_bin->num_paths; ++i) {
if (switch_bin->paths[i])
switch_bin->paths[i]->element = NULL;
}
PATH_UNLOCK (switch_bin);
G_OBJECT_CLASS (gst_switch_bin_parent_class)->dispose (object);
}
static void
gst_switch_bin_finalize (GObject * object)
{
GstSwitchBin *switch_bin = GST_SWITCH_BIN (object);
guint i;
if (switch_bin->last_caps != NULL)
gst_caps_unref (switch_bin->last_caps);
if (switch_bin->last_stream_start != NULL)
gst_event_unref (switch_bin->last_stream_start);
for (i = 0; i < switch_bin->num_paths; ++i) {
gst_object_unparent (GST_OBJECT (switch_bin->paths[i]));
}
g_free (switch_bin->paths);
G_OBJECT_CLASS (gst_switch_bin_parent_class)->finalize (object);
}
static void
gst_switch_bin_set_property (GObject * object, guint prop_id,
GValue const *value, GParamSpec * pspec)
{
GstSwitchBin *switch_bin = GST_SWITCH_BIN (object);
switch (prop_id) {
case PROP_NUM_PATHS:
PATH_LOCK (switch_bin);
gst_switch_bin_set_num_paths (switch_bin, g_value_get_uint (value));
PATH_UNLOCK_AND_CHECK (switch_bin);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_switch_bin_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstSwitchBin *switch_bin = GST_SWITCH_BIN (object);
switch (prop_id) {
case PROP_NUM_PATHS:
PATH_LOCK (switch_bin);
g_value_set_uint (value, switch_bin->num_paths);
PATH_UNLOCK_AND_CHECK (switch_bin);
break;
case PROP_CURRENT_PATH:
PATH_LOCK (switch_bin);
if (switch_bin->current_path) {
guint i;
for (i = 0; i < switch_bin->num_paths; ++i) {
if (switch_bin->paths[i] == switch_bin->current_path) {
g_value_set_uint (value, i);
break;
}
}
} else {
/* No valid path, return MAXUINT */
g_value_set_uint (value, G_MAXUINT);
}
PATH_UNLOCK (switch_bin);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gboolean
gst_switch_bin_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
GstSwitchBin *switch_bin = GST_SWITCH_BIN (parent);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_STREAM_START:
{
GST_DEBUG_OBJECT (switch_bin,
"stream-start event observed; copying it for later use");
gst_event_replace (&(switch_bin->last_stream_start), event);
return gst_pad_event_default (pad, parent, event);
}
case GST_EVENT_CAPS:
{
/* Intercept the caps event to switch to an appropriate path, then
* resume default caps event processing */
GstCaps *caps;
gboolean ret;
gst_event_parse_caps (event, &caps);
GST_DEBUG_OBJECT (switch_bin,
"sink pad got caps event with caps %" GST_PTR_FORMAT
" ; looking for matching path", (gpointer) caps);
PATH_LOCK (switch_bin);
ret = gst_switch_bin_select_path_for_caps (switch_bin, caps);
PATH_UNLOCK_AND_CHECK (switch_bin);
if (!ret) {
gst_event_unref (event);
return FALSE;
} else
return gst_pad_event_default (pad, parent, event);
}
default:
GST_DEBUG_OBJECT (switch_bin, "sink event: %s",
gst_event_type_get_name (GST_EVENT_TYPE (event)));
return gst_pad_event_default (pad, parent, event);
}
}
static gboolean
gst_switch_bin_handle_query (GstPad * pad, GstObject * parent, GstQuery * query,
char const *pad_name)
{
GstSwitchBin *switch_bin = GST_SWITCH_BIN (parent);
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_CAPS:
{
GstCaps *filter, *caps;
gst_query_parse_caps (query, &filter);
PATH_LOCK (switch_bin);
if (switch_bin->num_paths == 0) {
/* No paths exist - cannot return any caps */
caps = NULL;
} else if ((switch_bin->current_path == NULL)
|| (switch_bin->current_path->element == NULL)) {
/* Paths exist, but there is no current path (or the path is a dropping path,
* so no element exists) - just return all allowed caps */
caps =
gst_switch_bin_get_allowed_caps (switch_bin, pad, pad_name, filter);
} else {
/* Paths exist and there is a current path
* Forward the query to its element */
GstQuery *caps_query = gst_query_new_caps (NULL);
GstPad *element_pad =
gst_element_get_static_pad (switch_bin->current_path->element,
pad_name);
caps = NULL;
if (gst_pad_query (element_pad, caps_query)) {
GstCaps *query_caps;
gst_query_parse_caps_result (caps_query, &query_caps);
caps = gst_caps_copy (query_caps);
}
gst_query_unref (caps_query);
gst_object_unref (GST_OBJECT (element_pad));
}
PATH_UNLOCK (switch_bin);
if (caps != NULL) {
GST_DEBUG_OBJECT (switch_bin, "%s caps query: caps: %" GST_PTR_FORMAT,
pad_name, (gpointer) caps);
gst_query_set_caps_result (query, caps);
gst_caps_unref (caps);
return TRUE;
} else
return FALSE;
}
case GST_QUERY_ACCEPT_CAPS:
{
GstCaps *caps;
gboolean acceptable;
gst_query_parse_accept_caps (query, &caps);
PATH_LOCK (switch_bin);
acceptable = gst_switch_bin_are_caps_acceptable (switch_bin, caps);
PATH_UNLOCK (switch_bin);
GST_DEBUG_OBJECT (switch_bin,
"%s accept_caps query: acceptable: %d caps: %" GST_PTR_FORMAT,
pad_name, (gint) acceptable, (gpointer) caps);
gst_query_set_accept_caps_result (query, acceptable);
return TRUE;
}
default:
return gst_pad_query_default (pad, parent, query);
}
}
static gboolean
gst_switch_bin_sink_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
return gst_switch_bin_handle_query (pad, parent, query, "sink");
}
static gboolean
gst_switch_bin_src_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
return gst_switch_bin_handle_query (pad, parent, query, "src");
}
static gboolean
gst_switch_bin_set_num_paths (GstSwitchBin * switch_bin, guint new_num_paths)
{
guint i;
gboolean cur_path_removed = FALSE;
/* must be called with path lock held */
if (switch_bin->num_paths == new_num_paths) {
GST_DEBUG_OBJECT (switch_bin,
"no change in number of paths - ignoring call");
return TRUE;
} else if (switch_bin->num_paths < new_num_paths) {
/* New number of paths is larger -> N new paths need to be created & added,
* where N = new_num_paths - switch_bin->num_paths. */
GST_DEBUG_OBJECT (switch_bin, "adding %u new paths",
new_num_paths - switch_bin->num_paths);
switch_bin->paths =
g_realloc (switch_bin->paths, sizeof (GstObject *) * new_num_paths);
for (i = switch_bin->num_paths; i < new_num_paths; ++i) {
GstSwitchBinPath *path;
gchar *path_name;
/* default names would be something like "switchbinpath0" */
path_name = g_strdup_printf ("path%u", i);
switch_bin->paths[i] = path =
g_object_new (gst_switch_bin_path_get_type (), "name", path_name,
NULL);
path->bin = switch_bin;
gst_object_set_parent (GST_OBJECT (path), GST_OBJECT (switch_bin));
gst_child_proxy_child_added (GST_CHILD_PROXY (switch_bin),
G_OBJECT (path), path_name);
GST_DEBUG_OBJECT (switch_bin, "added path #%u \"%s\" (%p)", i, path_name,
(gpointer) path);
g_free (path_name);
}
} else {
/* New number of paths is smaller -> the last N paths need to be removed,
* where N = switch_bin->num_paths - new_num_paths. If one of the paths
* that are being removed is the current path, then a new current path
* is selected. */
gchar *path_name;
GST_DEBUG_OBJECT (switch_bin, "removing the last %u paths",
switch_bin->num_paths - new_num_paths);
for (i = new_num_paths; i < switch_bin->num_paths; ++i) {
GstSwitchBinPath *path = switch_bin->paths[i];
path_name = g_strdup (GST_OBJECT_NAME (path));
if (path == switch_bin->current_path) {
cur_path_removed = TRUE;
gst_switch_bin_switch_to_path (switch_bin, NULL);
GST_DEBUG_OBJECT (switch_bin,
"path #%u \"%s\" (%p) is the current path - selecting a new current path will be necessary",
i, path_name, (gpointer) (switch_bin->paths[i]));
}
gst_child_proxy_child_removed (GST_CHILD_PROXY (switch_bin),
G_OBJECT (path), path_name);
gst_object_unparent (GST_OBJECT (switch_bin->paths[i]));
GST_DEBUG_OBJECT (switch_bin, "removed path #%u \"%s\" (%p)", i,
path_name, (gpointer) (switch_bin->paths[i]));
g_free (path_name);
}
switch_bin->paths =
g_realloc (switch_bin->paths, sizeof (GstObject *) * new_num_paths);
}
switch_bin->num_paths = new_num_paths;
if (new_num_paths > 0) {
if (cur_path_removed) {
/* Select a new current path if the previous one was removed above */
if (switch_bin->last_caps != NULL) {
GST_DEBUG_OBJECT (switch_bin,
"current path was removed earlier - need to select a new one based on the last caps %"
GST_PTR_FORMAT, (gpointer) (switch_bin->last_caps));
return gst_switch_bin_select_path_for_caps (switch_bin,
switch_bin->last_caps);
} else {
/* This should not happen. Every time a current path is selected, the
* caps that were used for the selection are copied as the last_caps.
* So, if a current path exists, but last_caps is NULL, it indicates
* a bug. For example, if the current path was selected without calling
* gst_switch_bin_select_path_for_caps(). */
g_assert_not_reached ();
return FALSE; /* shuts up compiler warning */
}
} else
return TRUE;
} else
return gst_switch_bin_switch_to_path (switch_bin, NULL);
}
static gboolean
gst_switch_bin_select_path_for_caps (GstSwitchBin * switch_bin, GstCaps * caps)
{
/* must be called with path lock held */
gboolean ret;
GstSwitchBinPath *path;
path = gst_switch_bin_find_matching_path (switch_bin, caps);
if (path == NULL) {
/* No matching path found, the caps are incompatible. Report this and exit. */
GST_ELEMENT_ERROR (switch_bin, STREAM, WRONG_TYPE,
("could not find compatible path"), ("sink caps: %" GST_PTR_FORMAT,
(gpointer) caps));
ret = FALSE;
} else {
/* Matching path found. Try to switch to it. */
GST_DEBUG_OBJECT (switch_bin, "found matching path \"%s\" (%p) - switching",
GST_OBJECT_NAME (path), (gpointer) path);
ret = gst_switch_bin_switch_to_path (switch_bin, path);
}
if (ret && (caps != switch_bin->last_caps))
gst_caps_replace (&(switch_bin->last_caps), caps);
return ret;
}
static gboolean
gst_switch_bin_switch_to_path (GstSwitchBin * switch_bin,
GstSwitchBinPath * switch_bin_path)
{
/* must be called with path lock held */
gboolean ret = TRUE;
if (switch_bin_path != NULL)
GST_DEBUG_OBJECT (switch_bin, "switching to path \"%s\" (%p)",
GST_OBJECT_NAME (switch_bin_path), (gpointer) switch_bin_path);
else
GST_DEBUG_OBJECT (switch_bin,
"switching to NULL path (= disabling current path)");
/* No current path set and no path is to be set -> nothing to do */
if ((switch_bin_path == NULL) && (switch_bin->current_path == NULL))
return TRUE;
/* If this path is already the current one, do nothing */
if (switch_bin->current_path == switch_bin_path)
return TRUE;
/* Block incoming data to be able to safely switch */
gst_switch_bin_set_sinkpad_block (switch_bin, TRUE);
/* Unlink the current path's element (if there is a current path) */
if (switch_bin->current_path != NULL) {
GstSwitchBinPath *cur_path = switch_bin->current_path;
if (cur_path->element != NULL) {
gst_element_set_state (cur_path->element, GST_STATE_NULL);
gst_element_unlink (switch_bin->input_identity, cur_path->element);
}
gst_ghost_pad_set_target (GST_GHOST_PAD (switch_bin->srcpad), NULL);
switch_bin->current_path = NULL;
switch_bin->path_changed = TRUE;
}
/* Link the new path's element (if a new path is specified) */
if (switch_bin_path != NULL) {
if (switch_bin_path->element != NULL) {
GstPad *pad;
/* There is a path element. Link it into the pipeline. Data passes through
* it now, since its associated path just became the current one. */
/* TODO: currently, only elements with one "src" "sink" always-pad are supported;
* add support for request and sometimes pads */
pad = gst_element_get_static_pad (switch_bin_path->element, "src");
if (pad == NULL) {
GST_ERROR_OBJECT (switch_bin,
"path element has no static srcpad - cannot link");
ret = FALSE;
goto finish;
}
if (!gst_ghost_pad_set_target (GST_GHOST_PAD (switch_bin->srcpad), pad)) {
GST_ERROR_OBJECT (switch_bin,
"could not set the path element's srcpad as the ghost srcpad's target");
ret = FALSE;
}
gst_object_unref (GST_OBJECT (pad));
if (!ret)
goto finish;
if (!gst_element_link (switch_bin->input_identity,
switch_bin_path->element)) {
GST_ERROR_OBJECT (switch_bin,
"linking the path element's sinkpad failed ; check if the path element's sink caps and the upstream elements connected to the switchbin's sinkpad match");
ret = FALSE;
goto finish;
}
/* Unlock the element's state in case it was locked earlier
* so its state can be synced to the switchbin's */
gst_element_set_locked_state (switch_bin_path->element, FALSE);
if (!gst_element_sync_state_with_parent (switch_bin_path->element)) {
GST_ERROR_OBJECT (switch_bin,
"could not sync the path element's state with that of the switchbin");
ret = FALSE;
goto finish;
}
} else {
GstPad *srcpad;
/* There is no path element. This will probably yield an error
* into the pipeline unless we're shutting down */
GST_DEBUG_OBJECT (switch_bin, "path has no element ; will drop data");
srcpad = gst_element_get_static_pad (switch_bin->input_identity, "src");
g_assert (srcpad != NULL);
if (!gst_ghost_pad_set_target (GST_GHOST_PAD (switch_bin->srcpad),
srcpad)) {
GST_ERROR_OBJECT (switch_bin,
"could not set the path element's srcpad as the ghost srcpad's target");
ret = FALSE;
}
GST_DEBUG_OBJECT (switch_bin,
"pushing stream-start downstream before disabling");
gst_element_send_event (switch_bin->input_identity,
gst_event_ref (switch_bin->last_stream_start));
gst_object_unref (GST_OBJECT (srcpad));
}
}
switch_bin->current_path = switch_bin_path;
switch_bin->path_changed = TRUE;
/* If there is a new path to use, unblock the input */
if (switch_bin_path != NULL)
gst_switch_bin_set_sinkpad_block (switch_bin, FALSE);
finish:
return ret;
}
static GstSwitchBinPath *
gst_switch_bin_find_matching_path (GstSwitchBin * switch_bin,
GstCaps const *caps)
{
/* must be called with path lock held */
guint i;
for (i = 0; i < switch_bin->num_paths; ++i) {
GstSwitchBinPath *path = switch_bin->paths[i];
if (gst_caps_can_intersect (caps, path->caps))
return path;
}
return NULL;
}
static GstCaps *
gst_switch_bin_get_allowed_caps (GstSwitchBin * switch_bin,
GstPad * switch_bin_pad, gchar const *pad_name, GstCaps * filter)
{
/* must be called with path lock held */
guint i;
GstCaps *total_path_caps;
gboolean is_sink_pad =
(gst_pad_get_direction (switch_bin_pad) == GST_PAD_SINK);
/* The allowed caps are a combination of the caps of all paths, the
* filter caps, and the allowed caps as indicated by the result
* of the CAPS query on the current path's element.
* Since the CAPS query result can be influenced by an element's
* current state and link to other elements, the non-current
* path elements are not queried.
*
* In theory, it would be enough to just append all path caps. However,
* to refine this a bit further, in case of the current path, the
* path caps are first intersected with the result of the CAPS query.
* This narrows down the acceptable caps for this current path,
* hopefully providing better quality caps. */
if (switch_bin->num_paths == 0) {
/* No paths exist, so nothing can be returned */
GST_ELEMENT_ERROR (switch_bin, STREAM, FAILED, ("no paths defined"),
("there must be at least one path in order for switchbin to do anything"));
return NULL;
}
total_path_caps = gst_caps_new_empty ();
for (i = 0; i < switch_bin->num_paths; ++i) {
GstSwitchBinPath *path = switch_bin->paths[i];
if (path->element != NULL) {
GstPad *pad;
GstCaps *caps, *intersected_caps;
GstQuery *caps_query = NULL;
pad = gst_element_get_static_pad (path->element, pad_name);
caps_query = gst_query_new_caps (NULL);
/* Query the path element for allowed caps. If this is
* successful, intersect the returned caps with the path caps for the sink pad,
* and append the result of the intersection to the total_path_caps,
* or just append the result to the total_path_caps if collecting srcpad caps. */
if (gst_pad_query (pad, caps_query)) {
gst_query_parse_caps_result (caps_query, &caps);
if (is_sink_pad) {
intersected_caps = gst_caps_intersect (caps, path->caps);
} else {
intersected_caps = gst_caps_copy (caps);
}
gst_caps_append (total_path_caps, intersected_caps);
} else if (is_sink_pad) {
/* Just assume the sink pad has the path caps if the query failed */
gst_caps_append (total_path_caps, gst_caps_ref (path->caps));
}
gst_object_unref (GST_OBJECT (pad));
gst_query_unref (caps_query);
} else {
/* This is a path with no element (= is a dropping path),
* If querying the sink caps, append the path
* input caps, otherwise the output caps can be ANY */
if (is_sink_pad)
gst_caps_append (total_path_caps, gst_caps_ref (path->caps));
else
gst_caps_append (total_path_caps, gst_caps_new_any ());
}
}
/* Apply filter caps if present */
if (filter != NULL) {
GstCaps *tmp_caps = total_path_caps;
total_path_caps = gst_caps_intersect (tmp_caps, filter);
gst_caps_unref (tmp_caps);
}
return total_path_caps;
}
static gboolean
gst_switch_bin_are_caps_acceptable (GstSwitchBin * switch_bin,
GstCaps const *caps)
{
/* must be called with path lock held */
return (gst_switch_bin_find_matching_path (switch_bin, caps) != NULL);
}
static void
gst_switch_bin_set_sinkpad_block (GstSwitchBin * switch_bin, gboolean do_block)
{
GstPad *pad;
if ((do_block && (switch_bin->blocking_probe_id != 0)) || (!do_block
&& (switch_bin->blocking_probe_id == 0)))
return;
pad = gst_element_get_static_pad (switch_bin->input_identity, "sink");
if (do_block) {
switch_bin->blocking_probe_id =
gst_pad_add_probe (pad, GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM,
gst_switch_bin_blocking_pad_probe, NULL, NULL);
} else {
gst_pad_remove_probe (pad, switch_bin->blocking_probe_id);
switch_bin->blocking_probe_id = 0;
}
GST_DEBUG_OBJECT (switch_bin, "sinkpad block enabled: %d", do_block);
gst_object_unref (GST_OBJECT (pad));
}
static GstPadProbeReturn
gst_switch_bin_blocking_pad_probe (G_GNUC_UNUSED GstPad * pad,
GstPadProbeInfo * info, G_GNUC_UNUSED gpointer user_data)
{
if (GST_PAD_PROBE_INFO_TYPE (info) & GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM) {
GstEvent *event = GST_PAD_PROBE_INFO_EVENT (info);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_CAPS:
case GST_EVENT_STREAM_START:
return GST_PAD_PROBE_PASS;
default:
break;
}
}
return GST_PAD_PROBE_OK;
}
/************ GstSwitchBinPath ************/
typedef struct _GstSwitchBinPathClass GstSwitchBinPathClass;
#define GST_TYPE_SWITCH_BIN_PATH (gst_switch_bin_path_get_type())
#define GST_SWITCH_BIN_PATH(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj), GST_TYPE_SWITCH_BIN_PATH, GstSwitchBinPath))
#define GST_SWITCH_BIN_PATH_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass), GST_TYPE_SWITCH_BIN_PATH, GstSwitchBinPathClass))
#define GST_SWITCH_BIN_PATH_CAST(obj) ((GstSwitchBinPath *)(obj))
#define GST_IS_SWITCH_BIN_PATH(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj), GST_TYPE_SWITCH_BIN_PATH))
#define GST_IS_SWITCH_BIN_PATH_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass), GST_TYPE_SWITCH_BIN_PATH))
struct _GstSwitchBinPathClass
{
GstObjectClass parent_class;
};
enum
{
PROP_PATH_0,
PROP_ELEMENT,
PROP_PATH_CAPS
};
G_DEFINE_TYPE (GstSwitchBinPath, gst_switch_bin_path, GST_TYPE_OBJECT);
static void gst_switch_bin_path_dispose (GObject * object);
static void gst_switch_bin_path_set_property (GObject * object,
guint prop_id, GValue const *value, GParamSpec * pspec);
static void gst_switch_bin_path_get_property (GObject * object,
guint prop_id, GValue * value, GParamSpec * pspec);
static gboolean gst_switch_bin_path_use_new_element (GstSwitchBinPath *
switch_bin_path, GstElement * new_element);
static void
gst_switch_bin_path_class_init (GstSwitchBinPathClass * klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->dispose = GST_DEBUG_FUNCPTR (gst_switch_bin_path_dispose);
object_class->set_property =
GST_DEBUG_FUNCPTR (gst_switch_bin_path_set_property);
object_class->get_property =
GST_DEBUG_FUNCPTR (gst_switch_bin_path_get_property);
g_object_class_install_property (object_class,
PROP_ELEMENT,
g_param_spec_object ("element",
"Element",
"The path's element (if set to NULL, this path will drop any incoming data)",
GST_TYPE_ELEMENT, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)
);
g_object_class_install_property (object_class,
PROP_PATH_CAPS,
g_param_spec_boxed ("caps",
"Caps",
"Caps which, if they are a subset of the input caps, select this path as the active one",
GST_TYPE_CAPS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)
);
}
static void
gst_switch_bin_path_init (GstSwitchBinPath * switch_bin_path)
{
switch_bin_path->caps = gst_caps_new_any ();
switch_bin_path->element = NULL;
switch_bin_path->bin = NULL;
}
static void
gst_switch_bin_path_dispose (GObject * object)
{
GstSwitchBinPath *switch_bin_path = GST_SWITCH_BIN_PATH (object);
if (switch_bin_path->caps != NULL) {
gst_caps_unref (switch_bin_path->caps);
switch_bin_path->caps = NULL;
}
if (switch_bin_path->element != NULL) {
gst_switch_bin_path_use_new_element (switch_bin_path, NULL);
}
/* element is managed by the bin itself */
G_OBJECT_CLASS (gst_switch_bin_path_parent_class)->dispose (object);
}
static void
gst_switch_bin_path_set_property (GObject * object, guint prop_id,
GValue const *value, GParamSpec * pspec)
{
GstSwitchBinPath *switch_bin_path = GST_SWITCH_BIN_PATH (object);
switch (prop_id) {
case PROP_ELEMENT:
{
/* Get the object without modifying the refcount */
GstElement *new_element = GST_ELEMENT (g_value_get_object (value));
GST_OBJECT_LOCK (switch_bin_path);
PATH_LOCK (switch_bin_path->bin);
gst_switch_bin_path_use_new_element (switch_bin_path, new_element);
PATH_UNLOCK_AND_CHECK (switch_bin_path->bin);
GST_OBJECT_UNLOCK (switch_bin_path);
break;
}
case PROP_PATH_CAPS:
{
GstCaps *old_caps;
GstCaps const *new_caps = gst_value_get_caps (value);
GST_OBJECT_LOCK (switch_bin_path);
old_caps = switch_bin_path->caps;
if (new_caps == NULL) {
/* NULL caps are interpreted as ANY */
switch_bin_path->caps = gst_caps_new_any ();
} else
switch_bin_path->caps = gst_caps_copy (new_caps);
GST_OBJECT_UNLOCK (switch_bin_path);
if (old_caps != NULL)
gst_caps_unref (old_caps);
/* the new caps do not get applied right away
* they only start to be used with the next stream */
break;
}
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_switch_bin_path_get_property (GObject * object, guint prop_id,
GValue * value, GParamSpec * pspec)
{
GstSwitchBinPath *switch_bin_path = GST_SWITCH_BIN_PATH (object);
switch (prop_id) {
case PROP_ELEMENT:
/* If a path element exists, increase its refcount first. This is
* necessary because the code that called g_object_get() to fetch this
* element will also unref it when it is finished with it. */
if (switch_bin_path->element != NULL)
gst_object_ref (GST_OBJECT (switch_bin_path->element));
/* Use g_value_take_object() instead of g_value_set_object() as the latter
* increases the element's refcount for the duration of the GValue's lifetime */
g_value_take_object (value, switch_bin_path->element);
break;
case PROP_PATH_CAPS:
GST_OBJECT_LOCK (switch_bin_path);
gst_value_set_caps (value, switch_bin_path->caps);
GST_OBJECT_UNLOCK (switch_bin_path);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static gboolean
gst_switch_bin_path_use_new_element (GstSwitchBinPath * switch_bin_path,
GstElement * new_element)
{
/* Must be called with lock */
GstSwitchBinPath *current_path = switch_bin_path->bin->current_path;
gboolean is_current_path = (current_path == switch_bin_path);
/* Before switching the element, make sure it is not linked,
* which is the case if this is the current path. */
if (is_current_path)
gst_switch_bin_switch_to_path (switch_bin_path->bin, NULL);
/* Remove any present path element prior to using the new one */
if (switch_bin_path->element != NULL) {
gst_element_set_state (switch_bin_path->element, GST_STATE_NULL);
/* gst_bin_remove automatically unrefs the path element */
gst_bin_remove (GST_BIN (switch_bin_path->bin), switch_bin_path->element);
switch_bin_path->element = NULL;
}
/* If there *is* a new element, use it. new_element == NULL is a valid case;
* a NULL element is used in dropping paths, which will just use the drop probe
* to drop buffers if they become the current path. */
if (new_element != NULL) {
gst_bin_add (GST_BIN (switch_bin_path->bin), new_element);
switch_bin_path->element = new_element;
/* Lock the element's state in case. This prevents freezes, which can happen
* when an element from a not-current path tries to follow a state change,
* but is unable to do so as long as it isn't linked. By locking the state,
* it won't follow state changes, so the freeze does not happen. */
gst_element_set_locked_state (new_element, TRUE);
}
/* We are done. Switch back to the path if it is the current one,
* since we switched away from it earlier. */
if (is_current_path)
return gst_switch_bin_switch_to_path (switch_bin_path->bin, current_path);
else
return TRUE;
}
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