[gst-devel] [PATCH 1/3] gstreamer-0.8.9-gstfakesink.patch

[Thomas Vander Stichele]

Hi,

> [this patch is relative to gstreamer-0.8.9]

please put patches in bugzilla ! they get lost on the mailing list.


> This patch addresses two race conditions in Gst-Pads and Gst-Elements
> encountered in thread-based scenarios of GStreamer applications.

I assume this note is actually for the second patch you sent.

> This is a utility patch to the Fakesink plug-in. It enables applications
> to
> register for and receive the keyframes of a MPEG file - the file offset
> and corresponding timestamp of the keyframes are passed onto to the
> application. Given that information is present to some applications
> a-priori,
> applications can directly seek onto the exact keyframes without the
> decoder's
> help.

three things:

- the GST_BUFFER_KEY_UNIT flag is deprecated; there's no point in adding
code that uses it
- the functionality you want is already possible in two ways: using
PadProbes, or using handoff signals, and then checking for the flag you
want on the buffer
- rcvd_keyframe is a really bad signal name; you should choose either
rcvd_kfrm or received_keyframe.  My money is on the latter :)

Thomas


> 
> The patch creates a new signal 'rcvd_keyframe' and lets application
> register
> for that. When the fakesink receives the decoded raw video data and
> detects
> a keyframe it invokes the registered handlers of application passing the
> file offset and corresponding timestamp information for the keyframe.
> --
> diff -Naur gstreamer-0.8.9/gst/elements/gstfakesink.c
> gstreamer-0.8.9-ipvr/gst/elements/gstfakesink.c
> --- gstreamer-0.8.9/gst/elements/gstfakesink.c	2004-11-10
> 16:17:14.000000000 +0530
> +++ gstreamer-0.8.9-ipvr/gst/elements/gstfakesink.c	2005-04-25
> 13:01:15.466110280 +0530
> @@ -62,6 +62,17 @@
>    ARG_LAST_MESSAGE
>  };
>  
> +enum
> +{
> +  SIGNAL_HANDLE_KEYFRAME_FAKESINK,
> +  LAST_SIGNAL_FAKESINK
> +};
> +typedef struct _VID_KEYFRAME_FAKESINK {
> +  guint64 offset;
> +  gint64  timestamp;
> +} VID_KEYFRAME_FAKESINK;
> +static guint gst_fakesink_pad_signals[LAST_SIGNAL_FAKESINK] = { 0 };
> +
>  GstStaticPadTemplate fakesink_sink_template = GST_STATIC_PAD_TEMPLATE
> ("sink%d",
>      GST_PAD_SINK,
>      GST_PAD_REQUEST,
> @@ -177,6 +188,12 @@
>    gstelement_class->set_clock = GST_DEBUG_FUNCPTR
> (gst_fakesink_set_clock);
>    gstelement_class->change_state =
>        GST_DEBUG_FUNCPTR (gst_fakesink_change_state);
> +
> +  gst_fakesink_pad_signals[SIGNAL_HANDLE_KEYFRAME_FAKESINK] =
> +      g_signal_new("rcvd_keyframe", G_TYPE_FROM_CLASS(klass),
> +      G_SIGNAL_RUN_LAST, G_STRUCT_OFFSET(GstFakeSinkClass,
> rcvd_keyframe),
> +      NULL, NULL, gst_marshal_VOID__OBJECT_POINTER,
> +      G_TYPE_NONE, 2, G_TYPE_POINTER, G_TYPE_POINTER);
>  }
>  
>  static void
> @@ -320,6 +337,15 @@
>  
>    fakesink = GST_FAKESINK (GST_OBJECT_PARENT (pad));
>  
> +  if (GST_BUFFER_FLAG_IS_SET(buf, GST_BUFFER_KEY_UNIT)) {
> +    VID_KEYFRAME_FAKESINK tmp;
> +    tmp.offset = GST_BUFFER_OFFSET(buf);
> +    tmp.timestamp = GST_BUFFER_TIMESTAMP(buf);
> +    g_signal_emit(G_OBJECT(fakesink),
> +      gst_fakesink_pad_signals[SIGNAL_HANDLE_KEYFRAME_FAKESINK], 0,
> +      "fakesink", (void *)&tmp);
> +  }
> +
>    if (GST_IS_EVENT (buf)) {
>      GstEvent *event = GST_EVENT (buf);
>  
> diff -Naur gstreamer-0.8.9/gst/elements/gstfakesink.h
> gstreamer-0.8.9-ipvr/gst/elements/gstfakesink.h
> --- gstreamer-0.8.9/gst/elements/gstfakesink.h	2004-03-30
> 14:36:32.000000000 +0530
> +++ gstreamer-0.8.9-ipvr/gst/elements/gstfakesink.h	2005-04-25
> 13:01:33.095430216 +0530
> @@ -71,6 +71,7 @@
>  
>    /* signals */
>    void (*handoff) (GstElement *element, GstBuffer *buf, GstPad *pad);
> +  void (*rcvd_keyframe) (GstElement *fs, const char *name, void
> *vid_keyframe);
>  };
>  
>  GType gst_fakesink_get_type(void);
> 
> 
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