Add a built-in screencast recording facility
For development and demonstration purposes, it's neat to be able to record a screencast of gnome-shell without any external setup. Built-in recording can also give much better quality than is possible with a generic desktop recording, since we hook right into the paint loop. src/shell-recorder.[ch]: A general-purposes object to record a Clutter stage to a GStreamer stream. src/shell-recorder-src.[ch]: A simple GStreamer source element (similar to appsrc in the most recent versions of GStreamer) for injecting captured data into a GStreamer pipeline. src/test-recorder.c: Test program that records a simple animation. configure.ac src/Makefile.am: Add machinery to conditionally build ShellRecorder. tools/build/gnome-shell-build-setup.sh: Add gstreamer packages to the list of required packages for Fedora. js/ui/main.js: Hook up the recorder to a MetaScreen ::toggle-recording keybinding. http://bugzilla.gnome.org/show_bug.cgi?id=575290
This commit is contained in:
Owen W. Taylor
298
src/shell-recorder-src.c
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298
src/shell-recorder-src.c
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#include <gst/base/gstpushsrc.h>
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#include "shell-recorder-src.h"
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struct _ShellRecorderSrc
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{
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GstPushSrc parent;
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GMutex *mutex;
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GstCaps *caps;
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GAsyncQueue *queue;
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gboolean closed;
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guint memory_used;
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guint memory_used_update_idle;
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};
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struct _ShellRecorderSrcClass
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{
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GstPushSrcClass parent_class;
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};
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enum {
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PROP_0,
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PROP_CAPS,
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PROP_MEMORY_USED
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};
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/* Special marker value once the source is closed */
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#define RECORDER_QUEUE_END ((GstBuffer *)1)
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GST_BOILERPLATE(ShellRecorderSrc, shell_recorder_src, GstPushSrc, GST_TYPE_PUSH_SRC);
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static void
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shell_recorder_src_init (ShellRecorderSrc *src,
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ShellRecorderSrcClass *klass)
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{
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src->queue = g_async_queue_new ();
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src->mutex = g_mutex_new ();
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}
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static void
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shell_recorder_src_base_init (gpointer klass)
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{
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}
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static gboolean
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shell_recorder_src_memory_used_update_idle (gpointer data)
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{
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ShellRecorderSrc *src = data;
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g_mutex_lock (src->mutex);
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src->memory_used_update_idle = 0;
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g_mutex_unlock (src->mutex);
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g_object_notify (G_OBJECT (src), "memory-used");
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return FALSE;
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}
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/* The memory_used property is used to monitor buffer usage,
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* so we marshal notification back to the main loop thread.
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*/
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static void
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shell_recorder_src_update_memory_used (ShellRecorderSrc *src,
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int delta)
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{
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g_mutex_lock (src->mutex);
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src->memory_used += delta;
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if (src->memory_used_update_idle == 0)
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src->memory_used_update_idle = g_idle_add (shell_recorder_src_memory_used_update_idle, src);
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g_mutex_unlock (src->mutex);
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}
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/* The create() virtual function is responsible for returning the next buffer.
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* We just pop buffers off of the queue and block if necessary.
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*/
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static GstFlowReturn
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shell_recorder_src_create (GstPushSrc *push_src,
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GstBuffer **buffer_out)
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{
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ShellRecorderSrc *src = SHELL_RECORDER_SRC (push_src);
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GstBuffer *buffer;
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if (src->closed)
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return GST_FLOW_UNEXPECTED;
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buffer = g_async_queue_pop (src->queue);
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if (buffer == RECORDER_QUEUE_END)
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{
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/* Returning UNEXPECTED here will cause a EOS message to be sent */
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src->closed = TRUE;
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return GST_FLOW_UNEXPECTED;
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}
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shell_recorder_src_update_memory_used (src,
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- (int)(GST_BUFFER_SIZE(buffer) / 1024));
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*buffer_out = buffer;
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return GST_FLOW_OK;
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}
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static void
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shell_recorder_src_set_caps (ShellRecorderSrc *src,
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const GstCaps *caps)
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{
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if (caps == src->caps)
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return;
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if (src->caps != NULL)
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{
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gst_caps_unref (src->caps);
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src->caps = NULL;
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}
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if (caps)
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{
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/* The capabilities will be negotated with the downstream element
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* and set on the pad when the first buffer is pushed.
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*/
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src->caps = gst_caps_copy (caps);
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}
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else
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src->caps = NULL;
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}
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static void
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shell_recorder_src_finalize (GObject *object)
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{
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ShellRecorderSrc *src = SHELL_RECORDER_SRC (object);
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if (src->memory_used_update_idle)
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g_source_remove (src->memory_used_update_idle);
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shell_recorder_src_set_caps (src, NULL);
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g_async_queue_unref (src->queue);
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g_mutex_free (src->mutex);
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G_OBJECT_CLASS (parent_class)->finalize (object);
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}
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static void
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shell_recorder_src_set_property (GObject *object,
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guint prop_id,
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const GValue *value,
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GParamSpec *pspec)
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{
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ShellRecorderSrc *src = SHELL_RECORDER_SRC (object);
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switch (prop_id)
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{
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case PROP_CAPS:
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shell_recorder_src_set_caps (src, gst_value_get_caps (value));
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static void
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shell_recorder_src_get_property (GObject *object,
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guint prop_id,
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GValue *value,
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GParamSpec *pspec)
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{
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ShellRecorderSrc *src = SHELL_RECORDER_SRC (object);
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switch (prop_id)
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{
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case PROP_CAPS:
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gst_value_set_caps (value, src->caps);
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break;
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case PROP_MEMORY_USED:
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g_mutex_lock (src->mutex);
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g_value_set_uint (value, src->memory_used);
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g_mutex_unlock (src->mutex);
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break;
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default:
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G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
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break;
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}
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}
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static void
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shell_recorder_src_class_init (ShellRecorderSrcClass *klass)
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{
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GObjectClass *object_class = G_OBJECT_CLASS (klass);
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GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
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GstPushSrcClass *push_src_class = GST_PUSH_SRC_CLASS (klass);
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static GstStaticPadTemplate src_template =
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GST_STATIC_PAD_TEMPLATE ("src",
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GST_PAD_SRC,
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GST_PAD_ALWAYS,
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GST_STATIC_CAPS_ANY);
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object_class->finalize = shell_recorder_src_finalize;
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object_class->set_property = shell_recorder_src_set_property;
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object_class->get_property = shell_recorder_src_get_property;
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push_src_class->create = shell_recorder_src_create;
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g_object_class_install_property (object_class,
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PROP_CAPS,
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g_param_spec_boxed ("caps",
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"Caps",
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"Fixed GstCaps for the source",
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GST_TYPE_CAPS,
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G_PARAM_READWRITE));
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g_object_class_install_property (object_class,
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PROP_MEMORY_USED,
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g_param_spec_uint ("memory-used",
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"Memory Used",
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"Memory currently used by the queue (in kB)",
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0, G_MAXUINT, 0,
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G_PARAM_READABLE));
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gst_element_class_add_pad_template (element_class,
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gst_static_pad_template_get (&src_template));
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gst_element_class_set_details_simple (element_class,
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"ShellRecorderSrc",
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"Generic/Src",
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"Feed screen capture data to a pipeline",
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"Owen Taylor <otaylor@redhat.com>");
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}
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/**
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* shell_recorder_src_add_buffer:
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*
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* Adds a buffer to the internal queue to be pushed out at the next opportunity.
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* There is no flow control, so arbitrary amounts of memory may be used by
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* the buffers on the queue. The buffer contents must match the #GstCaps
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* set in the :caps property.
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*/
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void
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shell_recorder_src_add_buffer (ShellRecorderSrc *src,
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GstBuffer *buffer)
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{
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g_return_if_fail (SHELL_IS_RECORDER_SRC (src));
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g_return_if_fail (src->caps != NULL);
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gst_buffer_set_caps (buffer, src->caps);
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shell_recorder_src_update_memory_used (src,
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(int) (GST_BUFFER_SIZE(buffer) / 1024));
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g_async_queue_push (src->queue, gst_buffer_ref (buffer));
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}
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/**
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* shell_recorder_src_close:
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*
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* Indicates the end of the input stream. Once all previously added buffers have
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* been pushed out an end-of-stream message will be sent.
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*/
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void
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shell_recorder_src_close (ShellRecorderSrc *src)
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{
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/* We can't send a message to the source immediately or buffers that haven't
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* been pushed yet will be discarded. Instead stick a marker onto our own
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* queue to send an event once everything has been pushed.
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*/
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g_async_queue_push (src->queue, RECORDER_QUEUE_END);
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}
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static gboolean
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plugin_init (GstPlugin *plugin)
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{
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gst_element_register(plugin, "shellrecordersrc", GST_RANK_NONE,
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SHELL_TYPE_RECORDER_SRC);
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return TRUE;
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}
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/**
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* shell_recorder_src_register:
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* Registers a plugin holding our single element to use privately in
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* this application. Can safely be called multiple times.
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*/
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void
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shell_recorder_src_register (void)
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{
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static gboolean registered = FALSE;
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if (registered)
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return;
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gst_plugin_register_static (GST_VERSION_MAJOR, GST_VERSION_MINOR,
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"shellrecorder",
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"Plugin for ShellRecorder",
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plugin_init,
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"0.1",
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"LGPL",
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"gnome-shell", "gnome-shell", "http://live.gnome.org/GnomeShell");
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registered = TRUE;
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}
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