/* GStreamer * Copyright (C) 2007 David Schleef * (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., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ /** * SECTION:element-appsink * * Appsink is a sink plugin that supports many different methods for making * the application get a handle on the GStreamer data in a pipeline. Unlike * most GStreamer elements, Appsink provides external API functions. * * For the documentation of the API, please see the * libgstapp section in * the GStreamer Plugins Base Libraries documentation. * * Since: 0.10.22 */ /** * SECTION:gstappsink * @see_also: #GstBaseSink, appsrc * * Appsink is a sink plugin that supports many different methods for making * the application get a handle on the GStreamer data in a pipeline. Unlike * most GStreamer elements, Appsink provides external API functions. * * appsink can be used by linking to the gstappsink.h header file to access the * methods or by using the appsink action signals and properties. * * The normal way of retrieving buffers from appsink is by using the * gst_app_sink_pull_buffer() and gst_app_sink_pull_preroll() methods. * These methods block until a buffer becomes available in the sink or when the * sink is shut down or reaches EOS. * * Appsink will internally use a queue to collect buffers from the streaming * thread. If the application is not pulling buffers fast enough, this queue * will consume a lot of memory over time. The "max-buffers" property can be * used to limit the queue size. The "drop" property controls whether the * streaming thread blocks or if older buffers are dropped when the maximum * queue size is reached. Note that blocking the streaming thread can negatively * affect real-time performance and should be avoided. * * If a blocking behaviour is not desirable, setting the "emit-signals" property * to %TRUE will make appsink emit the "new-buffer" and "new-preroll" signals * when a buffer can be pulled without blocking. * * The "caps" property on appsink can be used to control the formats that * appsink can receive. This property can contain non-fixed caps, the format of * the pulled buffers can be obtained by getting the buffer caps. * * If one of the pull-preroll or pull-buffer methods return %NULL, the appsink * is stopped or in the EOS state. You can check for the EOS state with the * "eos" property or with the gst_app_sink_is_eos() method. * * The eos signal can also be used to be informed when the EOS state is reached * to avoid polling. * * Since: 0.10.22 * * Last reviewed on 2008-12-17 (0.10.22) */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #include "gstappsink.h" struct _GstAppSinkPrivate { GstCaps *caps; gboolean emit_signals; guint max_buffers; gboolean drop; GCond *cond; GMutex *mutex; GQueue *queue; GstBuffer *preroll; gboolean flushing; gboolean started; gboolean is_eos; }; GST_DEBUG_CATEGORY_STATIC (app_sink_debug); #define GST_CAT_DEFAULT app_sink_debug enum { /* signals */ SIGNAL_EOS, SIGNAL_NEW_PREROLL, SIGNAL_NEW_BUFFER, /* actions */ SIGNAL_PULL_PREROLL, SIGNAL_PULL_BUFFER, LAST_SIGNAL }; #define DEFAULT_PROP_EOS TRUE #define DEFAULT_PROP_EMIT_SIGNALS FALSE #define DEFAULT_PROP_MAX_BUFFERS 0 #define DEFAULT_PROP_DROP FALSE enum { PROP_0, PROP_CAPS, PROP_EOS, PROP_EMIT_SIGNALS, PROP_MAX_BUFFERS, PROP_DROP, PROP_LAST }; static GstStaticPadTemplate gst_app_sink_template = GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS_ANY); static void gst_app_sink_dispose (GObject * object); static void gst_app_sink_finalize (GObject * object); static void gst_app_sink_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec); static void gst_app_sink_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec); static gboolean gst_app_sink_unlock_start (GstBaseSink * bsink); static gboolean gst_app_sink_unlock_stop (GstBaseSink * bsink); static gboolean gst_app_sink_start (GstBaseSink * psink); static gboolean gst_app_sink_stop (GstBaseSink * psink); static gboolean gst_app_sink_event (GstBaseSink * sink, GstEvent * event); static GstFlowReturn gst_app_sink_preroll (GstBaseSink * psink, GstBuffer * buffer); static GstFlowReturn gst_app_sink_render (GstBaseSink * psink, GstBuffer * buffer); static GstCaps *gst_app_sink_getcaps (GstBaseSink * psink); static guint gst_app_sink_signals[LAST_SIGNAL] = { 0 }; GST_BOILERPLATE (GstAppSink, gst_app_sink, GstBaseSink, GST_TYPE_BASE_SINK); void gst_app_marshal_OBJECT__VOID (GClosure * closure, GValue * return_value, guint n_param_values, const GValue * param_values, gpointer invocation_hint, gpointer marshal_data) { typedef GstBuffer *(*GMarshalFunc_OBJECT__VOID) (gpointer data1, gpointer data2); register GMarshalFunc_OBJECT__VOID callback; register GCClosure *cc = (GCClosure *) closure; register gpointer data1, data2; GstBuffer *v_return; g_return_if_fail (return_value != NULL); g_return_if_fail (n_param_values == 1); if (G_CCLOSURE_SWAP_DATA (closure)) { data1 = closure->data; data2 = g_value_peek_pointer (param_values + 0); } else { data1 = g_value_peek_pointer (param_values + 0); data2 = closure->data; } callback = (GMarshalFunc_OBJECT__VOID) (marshal_data ? marshal_data : cc->callback); v_return = callback (data1, data2); gst_value_take_buffer (return_value, v_return); } static void gst_app_sink_base_init (gpointer g_class) { GstElementClass *element_class = GST_ELEMENT_CLASS (g_class); GST_DEBUG_CATEGORY_INIT (app_sink_debug, "appsink", 0, "appsink element"); gst_element_class_set_details_simple (element_class, "AppSink", "Generic/Sink", "Allow the application to get access to raw buffer", "David Schleef , Wim Taymans "); gst_element_class_add_pad_template (element_class, gst_static_pad_template_get (&gst_app_sink_template)); } static void gst_app_sink_class_init (GstAppSinkClass * klass) { GObjectClass *gobject_class = (GObjectClass *) klass; GstBaseSinkClass *basesink_class = (GstBaseSinkClass *) klass; gobject_class->dispose = gst_app_sink_dispose; gobject_class->finalize = gst_app_sink_finalize; gobject_class->set_property = gst_app_sink_set_property; gobject_class->get_property = gst_app_sink_get_property; g_object_class_install_property (gobject_class, PROP_CAPS, g_param_spec_boxed ("caps", "Caps", "The allowed caps for the sink pad", GST_TYPE_CAPS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); g_object_class_install_property (gobject_class, PROP_EOS, g_param_spec_boolean ("eos", "EOS", "Check if the sink is EOS or not started", DEFAULT_PROP_EOS, G_PARAM_READABLE | G_PARAM_STATIC_STRINGS)); g_object_class_install_property (gobject_class, PROP_EMIT_SIGNALS, g_param_spec_boolean ("emit-signals", "Emit signals", "Emit new-preroll and new-buffer signals", DEFAULT_PROP_EMIT_SIGNALS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); g_object_class_install_property (gobject_class, PROP_MAX_BUFFERS, g_param_spec_uint ("max-buffers", "Max Buffers", "The maximum number of buffers to queue internally (0 = unlimited)", 0, G_MAXUINT, DEFAULT_PROP_MAX_BUFFERS, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); g_object_class_install_property (gobject_class, PROP_DROP, g_param_spec_boolean ("drop", "Drop", "Drop old buffers when the buffer queue is filled", DEFAULT_PROP_DROP, G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS)); /** * GstAppSink::eos: * @appsink: the appsink element that emited the signal * * Signal that the end-of-stream has been reached. This signal is emited from * the steaming thread. */ gst_app_sink_signals[SIGNAL_EOS] = g_signal_new ("eos", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAppSinkClass, eos), NULL, NULL, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0, G_TYPE_NONE); /** * GstAppSink::new-preroll: * @appsink: the appsink element that emited the signal * * Signal that a new preroll buffer is available. * * This signal is emited from the steaming thread and only when the * "emit-signals" property is %TRUE. * * The new preroll buffer can be retrieved with the "pull-preroll" action * signal or gst_app_sink_pull_preroll() either from this signal callback * or from any other thread. * * Note that this signal is only emited when the "emit-signals" property is * set to %TRUE, which it is not by default for performance reasons. */ gst_app_sink_signals[SIGNAL_NEW_PREROLL] = g_signal_new ("new-preroll", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAppSinkClass, new_preroll), NULL, NULL, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0, G_TYPE_NONE); /** * GstAppSink::new-buffer: * @appsink: the appsink element that emited the signal * * Signal that a new buffer is available. * * This signal is emited from the steaming thread and only when the * "emit-signals" property is %TRUE. * * The new buffer can be retrieved with the "pull-buffer" action * signal or gst_app_sink_pull_buffer() either from this signal callback * or from any other thread. * * Note that this signal is only emited when the "emit-signals" property is * set to %TRUE, which it is not by default for performance reasons. */ gst_app_sink_signals[SIGNAL_NEW_BUFFER] = g_signal_new ("new-buffer", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET (GstAppSinkClass, new_buffer), NULL, NULL, g_cclosure_marshal_VOID__VOID, G_TYPE_NONE, 0, G_TYPE_NONE); /** * GstAppSink::pull-preroll: * @appsink: the appsink element to emit this signal on * * Get the last preroll buffer in @appsink. This was the buffer that caused the * appsink to preroll in the PAUSED state. This buffer can be pulled many times * and remains available to the application even after EOS. * * This function is typically used when dealing with a pipeline in the PAUSED * state. Calling this function after doing a seek will give the buffer right * after the seek position. * * Note that the preroll buffer will also be returned as the first buffer * when calling gst_app_sink_pull_buffer() or the "pull-buffer" action signal. * * If an EOS event was received before any buffers, this function returns * %NULL. Use gst_app_sink_is_eos () to check for the EOS condition. * * This function blocks until a preroll buffer or EOS is received or the appsink * element is set to the READY/NULL state. * * Returns: a #GstBuffer or NULL when the appsink is stopped or EOS. */ gst_app_sink_signals[SIGNAL_PULL_PREROLL] = g_signal_new ("pull-preroll", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstAppSinkClass, pull_preroll), NULL, NULL, gst_app_marshal_OBJECT__VOID, GST_TYPE_BUFFER, 0, G_TYPE_NONE); /** * GstAppSink::pull-buffer: * @appsink: the appsink element to emit this signal on * * This function blocks until a buffer or EOS becomes available or the appsink * element is set to the READY/NULL state. * * This function will only return buffers when the appsink is in the PLAYING * state. All rendered buffers will be put in a queue so that the application * can pull buffers at its own rate. * * Note that when the application does not pull buffers fast enough, the * queued buffers could consume a lot of memory, especially when dealing with * raw video frames. It's possible to control the behaviour of the queue with * the "drop" and "max-buffers" properties. * * If an EOS event was received before any buffers, this function returns * %NULL. Use gst_app_sink_is_eos () to check for the EOS condition. * * Returns: a #GstBuffer or NULL when the appsink is stopped or EOS. */ gst_app_sink_signals[SIGNAL_PULL_BUFFER] = g_signal_new ("pull-buffer", G_TYPE_FROM_CLASS (klass), G_SIGNAL_RUN_LAST | G_SIGNAL_ACTION, G_STRUCT_OFFSET (GstAppSinkClass, pull_buffer), NULL, NULL, gst_app_marshal_OBJECT__VOID, GST_TYPE_BUFFER, 0, G_TYPE_NONE); basesink_class->unlock = gst_app_sink_unlock_start; basesink_class->unlock_stop = gst_app_sink_unlock_stop; basesink_class->start = gst_app_sink_start; basesink_class->stop = gst_app_sink_stop; basesink_class->event = gst_app_sink_event; basesink_class->preroll = gst_app_sink_preroll; basesink_class->render = gst_app_sink_render; basesink_class->get_caps = gst_app_sink_getcaps; klass->pull_preroll = gst_app_sink_pull_preroll; klass->pull_buffer = gst_app_sink_pull_buffer; g_type_class_add_private (klass, sizeof (GstAppSinkPrivate)); } static void gst_app_sink_init (GstAppSink * appsink, GstAppSinkClass * klass) { appsink->priv = G_TYPE_INSTANCE_GET_PRIVATE (appsink, GST_TYPE_APP_SINK, GstAppSinkPrivate); appsink->priv->mutex = g_mutex_new (); appsink->priv->cond = g_cond_new (); appsink->priv->queue = g_queue_new (); appsink->priv->emit_signals = DEFAULT_PROP_EMIT_SIGNALS; appsink->priv->max_buffers = DEFAULT_PROP_MAX_BUFFERS; appsink->priv->drop = DEFAULT_PROP_DROP; } static void gst_app_sink_dispose (GObject * obj) { GstAppSink *appsink = GST_APP_SINK (obj); GstBuffer *buffer; GST_OBJECT_LOCK (appsink); if (appsink->priv->caps) { gst_caps_unref (appsink->priv->caps); appsink->priv->caps = NULL; } GST_OBJECT_UNLOCK (appsink); g_mutex_lock (appsink->priv->mutex); if (appsink->priv->preroll) { gst_buffer_unref (appsink->priv->preroll); appsink->priv->preroll = NULL; } while ((buffer = g_queue_pop_head (appsink->priv->queue))) gst_buffer_unref (buffer); g_mutex_unlock (appsink->priv->mutex); G_OBJECT_CLASS (parent_class)->dispose (obj); } static void gst_app_sink_finalize (GObject * obj) { GstAppSink *appsink = GST_APP_SINK (obj); g_mutex_free (appsink->priv->mutex); g_cond_free (appsink->priv->cond); g_queue_free (appsink->priv->queue); G_OBJECT_CLASS (parent_class)->finalize (obj); } static void gst_app_sink_set_property (GObject * object, guint prop_id, const GValue * value, GParamSpec * pspec) { GstAppSink *appsink = GST_APP_SINK (object); switch (prop_id) { case PROP_CAPS: gst_app_sink_set_caps (appsink, gst_value_get_caps (value)); break; case PROP_EMIT_SIGNALS: gst_app_sink_set_emit_signals (appsink, g_value_get_boolean (value)); break; case PROP_MAX_BUFFERS: gst_app_sink_set_max_buffers (appsink, g_value_get_uint (value)); break; case PROP_DROP: gst_app_sink_set_drop (appsink, g_value_get_boolean (value)); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); break; } } static void gst_app_sink_get_property (GObject * object, guint prop_id, GValue * value, GParamSpec * pspec) { GstAppSink *appsink = GST_APP_SINK (object); switch (prop_id) { case PROP_CAPS: { GstCaps *caps; caps = gst_app_sink_get_caps (appsink); gst_value_set_caps (value, caps); if (caps) gst_caps_unref (caps); break; } case PROP_EOS: g_value_set_boolean (value, gst_app_sink_is_eos (appsink)); break; case PROP_EMIT_SIGNALS: g_value_set_boolean (value, gst_app_sink_get_emit_signals (appsink)); break; case PROP_MAX_BUFFERS: g_value_set_uint (value, gst_app_sink_get_max_buffers (appsink)); break; case PROP_DROP: g_value_set_boolean (value, gst_app_sink_get_drop (appsink)); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); break; } } static gboolean gst_app_sink_unlock_start (GstBaseSink * bsink) { GstAppSink *appsink = GST_APP_SINK (bsink); g_mutex_lock (appsink->priv->mutex); GST_DEBUG_OBJECT (appsink, "unlock start"); appsink->priv->flushing = TRUE; g_cond_signal (appsink->priv->cond); g_mutex_unlock (appsink->priv->mutex); return TRUE; } static gboolean gst_app_sink_unlock_stop (GstBaseSink * bsink) { GstAppSink *appsink = GST_APP_SINK (bsink); g_mutex_lock (appsink->priv->mutex); GST_DEBUG_OBJECT (appsink, "unlock stop"); appsink->priv->flushing = FALSE; g_cond_signal (appsink->priv->cond); g_mutex_unlock (appsink->priv->mutex); return TRUE; } static void gst_app_sink_flush_unlocked (GstAppSink * appsink) { GstBuffer *buffer; GST_DEBUG_OBJECT (appsink, "flush stop appsink"); appsink->priv->is_eos = FALSE; gst_buffer_replace (&appsink->priv->preroll, NULL); while ((buffer = g_queue_pop_head (appsink->priv->queue))) gst_buffer_unref (buffer); g_cond_signal (appsink->priv->cond); } static gboolean gst_app_sink_start (GstBaseSink * psink) { GstAppSink *appsink = GST_APP_SINK (psink); g_mutex_lock (appsink->priv->mutex); GST_DEBUG_OBJECT (appsink, "starting"); appsink->priv->started = TRUE; g_mutex_unlock (appsink->priv->mutex); return TRUE; } static gboolean gst_app_sink_stop (GstBaseSink * psink) { GstAppSink *appsink = GST_APP_SINK (psink); g_mutex_lock (appsink->priv->mutex); GST_DEBUG_OBJECT (appsink, "stopping"); appsink->priv->flushing = TRUE; appsink->priv->started = FALSE; gst_app_sink_flush_unlocked (appsink); g_mutex_unlock (appsink->priv->mutex); return TRUE; } static gboolean gst_app_sink_event (GstBaseSink * sink, GstEvent * event) { GstAppSink *appsink = GST_APP_SINK (sink); switch (event->type) { case GST_EVENT_EOS: g_mutex_lock (appsink->priv->mutex); GST_DEBUG_OBJECT (appsink, "receiving EOS"); appsink->priv->is_eos = TRUE; g_cond_signal (appsink->priv->cond); g_mutex_unlock (appsink->priv->mutex); /* emit EOS now */ g_signal_emit (appsink, gst_app_sink_signals[SIGNAL_EOS], 0); break; case GST_EVENT_FLUSH_START: /* we don't have to do anything here, the base class will call unlock * which will make sure we exit the _render method */ GST_DEBUG_OBJECT (appsink, "received FLUSH_START"); break; case GST_EVENT_FLUSH_STOP: g_mutex_lock (appsink->priv->mutex); GST_DEBUG_OBJECT (appsink, "received FLUSH_STOP"); gst_app_sink_flush_unlocked (appsink); g_mutex_unlock (appsink->priv->mutex); break; default: break; } return TRUE; } static GstFlowReturn gst_app_sink_preroll (GstBaseSink * psink, GstBuffer * buffer) { GstAppSink *appsink = GST_APP_SINK (psink); gboolean emit; g_mutex_lock (appsink->priv->mutex); if (appsink->priv->flushing) goto flushing; GST_DEBUG_OBJECT (appsink, "setting preroll buffer %p", buffer); gst_buffer_replace (&appsink->priv->preroll, buffer); g_cond_signal (appsink->priv->cond); emit = appsink->priv->emit_signals; g_mutex_unlock (appsink->priv->mutex); if (emit) g_signal_emit (appsink, gst_app_sink_signals[SIGNAL_NEW_PREROLL], 0); return GST_FLOW_OK; flushing: { GST_DEBUG_OBJECT (appsink, "we are flushing"); g_mutex_unlock (appsink->priv->mutex); return GST_FLOW_WRONG_STATE; } } static GstFlowReturn gst_app_sink_render (GstBaseSink * psink, GstBuffer * buffer) { GstAppSink *appsink = GST_APP_SINK (psink); gboolean emit; g_mutex_lock (appsink->priv->mutex); if (appsink->priv->flushing) goto flushing; GST_DEBUG_OBJECT (appsink, "pushing render buffer %p on queue (%d)", buffer, appsink->priv->queue->length); while (appsink->priv->max_buffers > 0 && appsink->priv->queue->length >= appsink->priv->max_buffers) { if (appsink->priv->drop) { GstBuffer *buf; /* we need to drop the oldest buffer and try again */ buf = g_queue_pop_head (appsink->priv->queue); GST_DEBUG_OBJECT (appsink, "dropping old buffer %p", buf); gst_buffer_unref (buf); } else { GST_DEBUG_OBJECT (appsink, "waiting for free space, length %d >= %d", appsink->priv->queue->length, appsink->priv->max_buffers); /* wait for a buffer to be removed or flush */ g_cond_wait (appsink->priv->cond, appsink->priv->mutex); if (appsink->priv->flushing) goto flushing; } } /* we need to ref the buffer when pushing it in the queue */ g_queue_push_tail (appsink->priv->queue, gst_buffer_ref (buffer)); g_cond_signal (appsink->priv->cond); emit = appsink->priv->emit_signals; g_mutex_unlock (appsink->priv->mutex); if (emit) g_signal_emit (appsink, gst_app_sink_signals[SIGNAL_NEW_BUFFER], 0); return GST_FLOW_OK; flushing: { GST_DEBUG_OBJECT (appsink, "we are flushing"); g_mutex_unlock (appsink->priv->mutex); return GST_FLOW_WRONG_STATE; } } static GstCaps * gst_app_sink_getcaps (GstBaseSink * psink) { GstCaps *caps; GstAppSink *appsink = GST_APP_SINK (psink); GST_OBJECT_LOCK (appsink); if ((caps = appsink->priv->caps)) gst_caps_ref (caps); GST_DEBUG_OBJECT (appsink, "got caps %" GST_PTR_FORMAT, caps); GST_OBJECT_UNLOCK (appsink); return caps; } /* external API */ /** * gst_app_sink_set_caps: * @appsink: a #GstAppSink * @caps: caps to set * * Set the capabilities on the appsink element. This function takes * a copy of the caps structure. After calling this method, the sink will only * accept caps that match @caps. If @caps is non-fixed, you must check the caps * on the buffers to get the actual used caps. * * Since: 0.10.22 */ void gst_app_sink_set_caps (GstAppSink * appsink, const GstCaps * caps) { GstCaps *old; g_return_if_fail (appsink != NULL); g_return_if_fail (GST_IS_APP_SINK (appsink)); GST_OBJECT_LOCK (appsink); GST_DEBUG_OBJECT (appsink, "setting caps to %" GST_PTR_FORMAT, caps); if ((old = appsink->priv->caps) != caps) { if (caps) appsink->priv->caps = gst_caps_copy (caps); else appsink->priv->caps = NULL; if (old) gst_caps_unref (old); } GST_OBJECT_UNLOCK (appsink); } /** * gst_app_sink_get_caps: * @appsink: a #GstAppSink * * Get the configured caps on @appsink. * * Returns: the #GstCaps accepted by the sink. gst_caps_unref() after usage. * * Since: 0.10.22 */ GstCaps * gst_app_sink_get_caps (GstAppSink * appsink) { GstCaps *caps; g_return_val_if_fail (appsink != NULL, NULL); g_return_val_if_fail (GST_IS_APP_SINK (appsink), NULL); GST_OBJECT_LOCK (appsink); if ((caps = appsink->priv->caps)) gst_caps_ref (caps); GST_DEBUG_OBJECT (appsink, "getting caps of %" GST_PTR_FORMAT, caps); GST_OBJECT_UNLOCK (appsink); return caps; } /** * gst_app_sink_is_eos: * @appsink: a #GstAppSink * * Check if @appsink is EOS, which is when no more buffers can be pulled because * an EOS event was received. * * This function also returns %TRUE when the appsink is not in the PAUSED or * PLAYING state. * * Returns: %TRUE if no more buffers can be pulled and the appsink is EOS. * * Since: 0.10.22 */ gboolean gst_app_sink_is_eos (GstAppSink * appsink) { gboolean ret; g_return_val_if_fail (appsink != NULL, FALSE); g_return_val_if_fail (GST_IS_APP_SINK (appsink), FALSE); g_mutex_lock (appsink->priv->mutex); if (!appsink->priv->started) goto not_started; if (appsink->priv->is_eos && g_queue_is_empty (appsink->priv->queue)) { GST_DEBUG_OBJECT (appsink, "we are EOS and the queue is empty"); ret = TRUE; } else { GST_DEBUG_OBJECT (appsink, "we are not yet EOS"); ret = FALSE; } g_mutex_unlock (appsink->priv->mutex); return ret; not_started: { GST_DEBUG_OBJECT (appsink, "we are stopped, return TRUE"); g_mutex_unlock (appsink->priv->mutex); return TRUE; } } /** * gst_app_sink_set_emit_signals: * @appsink: a #GstAppSink * @emit: the new state * * Make appsink emit the "new-preroll" and "new-buffer" signals. This option is * by default disabled because signal emission is expensive and unneeded when * the application prefers to operate in pull mode. * * Since: 0.10.22 */ void gst_app_sink_set_emit_signals (GstAppSink * appsink, gboolean emit) { g_return_if_fail (GST_IS_APP_SINK (appsink)); g_mutex_lock (appsink->priv->mutex); appsink->priv->emit_signals = emit; g_mutex_unlock (appsink->priv->mutex); } /** * gst_app_sink_get_emit_signals: * @appsink: a #GstAppSink * * Check if appsink will emit the "new-preroll" and "new-buffer" signals. * * Returns: %TRUE if @appsink is emiting the "new-preroll" and "new-buffer" * signals. * * Since: 0.10.22 */ gboolean gst_app_sink_get_emit_signals (GstAppSink * appsink) { gboolean result; g_return_val_if_fail (GST_IS_APP_SINK (appsink), FALSE); g_mutex_lock (appsink->priv->mutex); result = appsink->priv->emit_signals; g_mutex_unlock (appsink->priv->mutex); return result; } /** * gst_app_sink_set_max_buffers: * @appsink: a #GstAppSink * @max: the maximum number of buffers to queue * * Set the maximum amount of buffers that can be queued in @appsink. After this * amount of buffers are queued in appsink, any more buffers will block upstream * elements until a buffer is pulled from @appsink. * * Since: 0.10.22 */ void gst_app_sink_set_max_buffers (GstAppSink * appsink, guint max) { g_return_if_fail (GST_IS_APP_SINK (appsink)); g_mutex_lock (appsink->priv->mutex); if (max != appsink->priv->max_buffers) { appsink->priv->max_buffers = max; /* signal the change */ g_cond_signal (appsink->priv->cond); } g_mutex_unlock (appsink->priv->mutex); } /** * gst_app_sink_get_max_buffers: * @appsink: a #GstAppSink * * Get the maximum amount of buffers that can be queued in @appsink. * * Returns: The maximum amount of buffers that can be queued. * * Since: 0.10.22 */ guint gst_app_sink_get_max_buffers (GstAppSink * appsink) { guint result; g_return_val_if_fail (GST_IS_APP_SINK (appsink), 0); g_mutex_lock (appsink->priv->mutex); result = appsink->priv->max_buffers; g_mutex_unlock (appsink->priv->mutex); return result; } /** * gst_app_sink_set_drop: * @appsink: a #GstAppSink * @drop: the new state * * Instruct @appsink to drop old buffers when the maximum amount of queued * buffers is reached. * * Since: 0.10.22 */ void gst_app_sink_set_drop (GstAppSink * appsink, gboolean drop) { g_return_if_fail (GST_IS_APP_SINK (appsink)); g_mutex_lock (appsink->priv->mutex); if (appsink->priv->drop != drop) { appsink->priv->drop = drop; /* signal the change */ g_cond_signal (appsink->priv->cond); } g_mutex_unlock (appsink->priv->mutex); } /** * gst_app_sink_get_drop: * @appsink: a #GstAppSink * * Check if @appsink will drop old buffers when the maximum amount of queued * buffers is reached. * * Returns: %TRUE if @appsink is dropping old buffers when the queue is * filled. * * Since: 0.10.22 */ gboolean gst_app_sink_get_drop (GstAppSink * appsink) { gboolean result; g_return_val_if_fail (GST_IS_APP_SINK (appsink), FALSE); g_mutex_lock (appsink->priv->mutex); result = appsink->priv->drop; g_mutex_unlock (appsink->priv->mutex); return result; } /** * gst_app_sink_pull_preroll: * @appsink: a #GstAppSink * * Get the last preroll buffer in @appsink. This was the buffer that caused the * appsink to preroll in the PAUSED state. This buffer can be pulled many times * and remains available to the application even after EOS. * * This function is typically used when dealing with a pipeline in the PAUSED * state. Calling this function after doing a seek will give the buffer right * after the seek position. * * Note that the preroll buffer will also be returned as the first buffer * when calling gst_app_sink_pull_buffer(). * * If an EOS event was received before any buffers, this function returns * %NULL. Use gst_app_sink_is_eos () to check for the EOS condition. * * This function blocks until a preroll buffer or EOS is received or the appsink * element is set to the READY/NULL state. * * Returns: a #GstBuffer or NULL when the appsink is stopped or EOS. * * Since: 0.10.22 */ GstBuffer * gst_app_sink_pull_preroll (GstAppSink * appsink) { GstBuffer *buf = NULL; g_return_val_if_fail (appsink != NULL, NULL); g_return_val_if_fail (GST_IS_APP_SINK (appsink), NULL); g_mutex_lock (appsink->priv->mutex); while (TRUE) { GST_DEBUG_OBJECT (appsink, "trying to grab a buffer"); if (!appsink->priv->started) goto not_started; if (appsink->priv->preroll != NULL) break; if (appsink->priv->is_eos) goto eos; /* nothing to return, wait */ GST_DEBUG_OBJECT (appsink, "waiting for the preroll buffer"); g_cond_wait (appsink->priv->cond, appsink->priv->mutex); } buf = gst_buffer_ref (appsink->priv->preroll); GST_DEBUG_OBJECT (appsink, "we have the preroll buffer %p", buf); g_mutex_unlock (appsink->priv->mutex); return buf; /* special conditions */ eos: { GST_DEBUG_OBJECT (appsink, "we are EOS, return NULL"); g_mutex_unlock (appsink->priv->mutex); return NULL; } not_started: { GST_DEBUG_OBJECT (appsink, "we are stopped, return NULL"); g_mutex_unlock (appsink->priv->mutex); return NULL; } } /** * gst_app_sink_pull_buffer: * @appsink: a #GstAppSink * * This function blocks until a buffer or EOS becomes available or the appsink * element is set to the READY/NULL state. * * This function will only return buffers when the appsink is in the PLAYING * state. All rendered buffers will be put in a queue so that the application * can pull buffers at its own rate. Note that when the application does not * pull buffers fast enough, the queued buffers could consume a lot of memory, * especially when dealing with raw video frames. * * If an EOS event was received before any buffers, this function returns * %NULL. Use gst_app_sink_is_eos () to check for the EOS condition. * * Returns: a #GstBuffer or NULL when the appsink is stopped or EOS. * * Since: 0.10.22 */ GstBuffer * gst_app_sink_pull_buffer (GstAppSink * appsink) { GstBuffer *buf = NULL; g_return_val_if_fail (appsink != NULL, NULL); g_return_val_if_fail (GST_IS_APP_SINK (appsink), NULL); g_mutex_lock (appsink->priv->mutex); while (TRUE) { GST_DEBUG_OBJECT (appsink, "trying to grab a buffer"); if (!appsink->priv->started) goto not_started; if (!g_queue_is_empty (appsink->priv->queue)) break; if (appsink->priv->is_eos) goto eos; /* nothing to return, wait */ GST_DEBUG_OBJECT (appsink, "waiting for a buffer"); g_cond_wait (appsink->priv->cond, appsink->priv->mutex); } buf = g_queue_pop_head (appsink->priv->queue); GST_DEBUG_OBJECT (appsink, "we have a buffer %p", buf); g_cond_signal (appsink->priv->cond); g_mutex_unlock (appsink->priv->mutex); return buf; /* special conditions */ eos: { GST_DEBUG_OBJECT (appsink, "we are EOS, return NULL"); g_mutex_unlock (appsink->priv->mutex); return NULL; } not_started: { GST_DEBUG_OBJECT (appsink, "we are stopped, return NULL"); g_mutex_unlock (appsink->priv->mutex); return NULL; } }