Implement null video sink.

Originally committed as revision 21242 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/libavfilter.texi

@@ -213,4 +213,14 @@ the configured source.
 The default values of ``width'' and ``height'' are respectively 352
 and 288 (corresponding to the CIF size format).
 
+@chapter Available video sinks
+
+Below is a description of the currently available video sinks.
+
+@section nullsink
+
+Null video sink, do absolutely nothing with the input video. It is
+mainly useful as a template and to be employed in analysis / debugging
+tools.
+
 @bye

libavfilter/Makefile

@@ -22,4 +22,6 @@ OBJS-$(CONFIG_VFLIP_FILTER)                  += vf_vflip.o
 
 OBJS-$(CONFIG_NULLSRC_FILTER)                += vsrc_nullsrc.o
 
+OBJS-$(CONFIG_NULLSINK_FILTER)               += vsink_nullsink.o
+
 include $(SUBDIR)../subdir.mak

libavfilter/allfilters.c

@@ -43,4 +43,6 @@ void avfilter_register_all(void)
     REGISTER_FILTER (VFLIP, vflip, vf);
 
     REGISTER_FILTER (NULLSRC, nullsrc, vsrc);
+
+    REGISTER_FILTER(NULLSINK, nullsink, vsink);
 }

libavfilter/avfilter.h

@@ -25,7 +25,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  1
-#define LIBAVFILTER_VERSION_MINOR 16
+#define LIBAVFILTER_VERSION_MINOR 17
 #define LIBAVFILTER_VERSION_MICRO  0
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vsink_nullsink.c

@@ -0,0 +1,45 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avfilter.h"
+
+static void start_frame(AVFilterLink *link, AVFilterPicRef *picref)
+{
+}
+
+static void end_frame(AVFilterLink *link)
+{
+}
+
+AVFilter avfilter_vsink_nullsink = {
+    .name        = "nullsink",
+    .description = "Do absolutely nothing with the input video.",
+
+    .priv_size = 0,
+
+    .inputs    = (AVFilterPad[]) {
+        {
+            .name            = "default",
+            .type            = CODEC_TYPE_VIDEO,
+            .start_frame     = start_frame,
+            .end_frame       = end_frame,
+        },
+        { .name = NULL},
+    },
+    .outputs   = (AVFilterPad[]) {{ .name = NULL }},
+};