closedcaption: add line21 encoder

This element acts as a counterpart of line21encoder.

Also adds a simple test validating each element using the
other.

5 files changed, 300 insertions, 4 deletions

diff --git a/ext/closedcaption/Makefile.am b/ext/closedcaption/Makefile.am
index dd6914215..7a2a839a8 100644
--- a/ext/closedcaption/Makefile.am
+++ b/ext/closedcaption/Makefile.am
@@ -3,13 +3,16 @@ plugin_LTLIBRARIES = libgstclosedcaption.la
 zvbi_sources = \
 	bit_slicer.c \
 	decoder.c \
-        raw_decoder.c \
+	io-sim.c \
+	raw_decoder.c \
 	sampling_par.c
 
 zvbi_headers = \
 	bcd.h \
 	bit_slicer.h \
 	decoder.h \
+	hamm.h \
+	io-sim.h \
 	macros.h \
 	misc.h \
 	raw_decoder.h \
@@ -25,6 +28,7 @@ libgstclosedcaption_la_SOURCES = \
 	gstcea708decoder.c \
 	gstceaccoverlay.c \
 	gstline21dec.c \
+	gstline21enc.c \
 	gstclosedcaption.c
 
 libgstclosedcaption_la_CFLAGS = \
@@ -37,7 +41,8 @@ libgstclosedcaption_la_LIBADD = \
 	$(GST_PLUGINS_BASE_LIBS) -lgstvideo-@GST_API_VERSION@ \
 	$(GST_BASE_LIBS) \
 	$(GST_LIBS) \
-	$(PANGO_LIBS)
+	$(PANGO_LIBS) \
+	$(LIBM)
 
 libgstclosedcaption_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
 
@@ -48,4 +53,5 @@ noinst_HEADERS = \
 	gstcea708decoder.h \
 	gstceaccoverlay.h \
 	gstline21dec.h \
+	gstline21enc.h \
 	$(zvbi_headers)
diff --git a/ext/closedcaption/gstclosedcaption.c b/ext/closedcaption/gstclosedcaption.c
index dde31c8f8..daab0af3b 100644
--- a/ext/closedcaption/gstclosedcaption.c
+++ b/ext/closedcaption/gstclosedcaption.c
@@ -30,6 +30,7 @@
 #include "gstccextractor.h"
 #include "gstline21dec.h"
 #include "gstceaccoverlay.h"
+#include "gstline21enc.h"
 
 static gboolean
 closedcaption_init (GstPlugin * plugin)
@@ -51,6 +52,9 @@ closedcaption_init (GstPlugin * plugin)
   ret &= gst_element_register (plugin, "cc708overlay", GST_RANK_PRIMARY,
       GST_TYPE_CEA_CC_OVERLAY);
 
+  ret &= gst_element_register (plugin, "line21encoder", GST_RANK_NONE,
+      GST_TYPE_LINE21ENCODER);
+
   return ret;
 }
 
diff --git a/ext/closedcaption/gstline21enc.c b/ext/closedcaption/gstline21enc.c
new file mode 100644
index 000000000..1a63fe542
--- /dev/null
+++ b/ext/closedcaption/gstline21enc.c
@@ -0,0 +1,224 @@
+/*
+ * GStreamer
+ * Copyright (C) 2019 Mathieu Duponchelle <mathieu@centricular.com>
+ *
+ * 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-line21encoder
+ * @title: line21encoder
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <gst/gst.h>
+#include <gst/video/video.h>
+#include <string.h>
+
+#include "gstline21enc.h"
+#include "io-sim.h"
+
+GST_DEBUG_CATEGORY_STATIC (gst_line_21_encoder_debug);
+#define GST_CAT_DEFAULT gst_line_21_encoder_debug
+
+#define CAPS "video/x-raw, format={ I420, YUY2, YVYU, UYVY, VYUY }, width=(int)720, height=(int)[ 23, MAX ], interlace-mode=interleaved"
+
+static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (CAPS));
+
+static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS (CAPS));
+
+G_DEFINE_TYPE (GstLine21Encoder, gst_line_21_encoder, GST_TYPE_VIDEO_FILTER);
+#define parent_class gst_line_21_encoder_parent_class
+
+static gboolean gst_line_21_encoder_set_info (GstVideoFilter * filter,
+    GstCaps * incaps, GstVideoInfo * in_info,
+    GstCaps * outcaps, GstVideoInfo * out_info);
+static GstFlowReturn gst_line_21_encoder_transform_ip (GstVideoFilter * filter,
+    GstVideoFrame * frame);
+
+static void
+gst_line_21_encoder_class_init (GstLine21EncoderClass * klass)
+{
+  GstElementClass *gstelement_class;
+  GstVideoFilterClass *filter_class;
+
+  gstelement_class = (GstElementClass *) klass;
+  filter_class = (GstVideoFilterClass *) klass;
+
+  gst_element_class_set_static_metadata (gstelement_class,
+      "Line 21 CC Encoder",
+      "Filter/Video/ClosedCaption",
+      "Inject line21 CC in SD video streams",
+      "Mathieu Duponchelle <mathieu@centricular.com>");
+
+  gst_element_class_add_static_pad_template (gstelement_class, &sinktemplate);
+  gst_element_class_add_static_pad_template (gstelement_class, &srctemplate);
+
+  filter_class->set_info = gst_line_21_encoder_set_info;
+  filter_class->transform_frame_ip = gst_line_21_encoder_transform_ip;
+
+  GST_DEBUG_CATEGORY_INIT (gst_line_21_encoder_debug, "line21encoder",
+      0, "Line 21 CC Encoder");
+  vbi_initialize_gst_debug ();
+}
+
+static void
+gst_line_21_encoder_init (GstLine21Encoder * filter)
+{
+}
+
+static vbi_pixfmt
+vbi_pixfmt_from_gst_video_format (GstVideoFormat format)
+{
+  switch (format) {
+    case GST_VIDEO_FORMAT_I420:
+      return VBI_PIXFMT_YUV420;
+    case GST_VIDEO_FORMAT_YUY2:
+      return VBI_PIXFMT_YUYV;
+    case GST_VIDEO_FORMAT_YVYU:
+      return VBI_PIXFMT_YVYU;
+    case GST_VIDEO_FORMAT_UYVY:
+      return VBI_PIXFMT_UYVY;
+    case GST_VIDEO_FORMAT_VYUY:
+      return VBI_PIXFMT_VYUY;
+    default:
+      g_assert_not_reached ();
+      return (vbi_pixfmt) 0;
+  }
+#undef NATIVE_VBI_FMT
+}
+
+static gboolean
+gst_line_21_encoder_set_info (GstVideoFilter * filter,
+    GstCaps * incaps, GstVideoInfo * in_info,
+    GstCaps * outcaps, GstVideoInfo * out_info)
+{
+  GstLine21Encoder *self = GST_LINE21ENCODER (filter);
+
+  self->info = *in_info;
+
+  /*
+   * Set up blank / black / white levels fit for NTSC, no actual relation
+   * with the height of the video
+   */
+  self->sp.scanning = 525;
+  /* The pixel format */
+  self->sp.sampling_format =
+      vbi_pixfmt_from_gst_video_format (GST_VIDEO_INFO_FORMAT (&self->info));
+  /* Sampling rate. For BT.601 it's 13.5MHz */
+  self->sp.sampling_rate = 13.5e6;
+  /* Stride */
+  self->sp.bytes_per_line = GST_VIDEO_INFO_COMP_STRIDE (&self->info, 0);
+  /* Horizontal offset of the VBI image */
+  self->sp.offset = 122;
+
+  /* FIXME: magic numbers */
+  self->sp.start[0] = 21;
+  self->sp.count[0] = 1;
+  self->sp.start[1] = 284;
+  self->sp.count[1] = 1;
+
+  self->sp.interlaced = FALSE;
+  self->sp.synchronous = TRUE;
+
+  return TRUE;
+}
+
+static GstFlowReturn
+gst_line_21_encoder_transform_ip (GstVideoFilter * filter,
+    GstVideoFrame * frame)
+{
+  GstLine21Encoder *self = GST_LINE21ENCODER (filter);
+  GstVideoCaptionMeta *cc_meta;
+  guint8 *buf;
+  vbi_sliced sliced[2];
+  gpointer iter = NULL;
+  GstFlowReturn ret = GST_FLOW_ERROR;
+
+  sliced[0].id = VBI_SLICED_CAPTION_525_F1;
+  sliced[0].line = self->sp.start[0];
+  sliced[1].id = VBI_SLICED_CAPTION_525_F2;
+  sliced[1].line = self->sp.start[1];
+
+  sliced[0].data[0] = 0x80;
+  sliced[0].data[1] = 0x80;
+  sliced[1].data[0] = 0x80;
+  sliced[1].data[1] = 0x80;
+
+  /* We loop over caption metas until we find the first CEA608 meta */
+  while ((cc_meta = (GstVideoCaptionMeta *)
+          gst_buffer_iterate_meta_filtered (frame->buffer, &iter,
+              GST_VIDEO_CAPTION_META_API_TYPE))) {
+    guint n = cc_meta->size;
+    guint i;
+
+    if (cc_meta->caption_type != GST_VIDEO_CAPTION_TYPE_CEA608_S334_1A)
+      continue;
+
+    if (n % 3 != 0) {
+      GST_ERROR_OBJECT (filter, "Invalid S334-1A CEA608 buffer size");
+      goto done;
+    }
+
+    n /= 3;
+
+    if (n >= 3) {
+      GST_ERROR_OBJECT (filter, "Too many S334-1A CEA608 triplets %u", n);
+      goto done;
+    }
+
+    for (i = 0; i < n; i++) {
+      if (cc_meta->data[i * 3] & 0x80) {
+        sliced[0].data[0] = cc_meta->data[i * 3 + 1];
+        sliced[0].data[1] = cc_meta->data[i * 3 + 2];
+      } else {
+        sliced[1].data[0] = cc_meta->data[i * 3 + 1];
+        sliced[1].data[1] = cc_meta->data[i * 3 + 2];
+      }
+    }
+
+    break;
+  }
+
+  /* We've encoded this meta, it can now be removed */
+  if (cc_meta)
+    gst_buffer_remove_meta (frame->buffer, (GstMeta *) cc_meta);
+
+  buf =
+      (guint8 *) GST_VIDEO_FRAME_PLANE_DATA (frame,
+      0) + 21 * GST_VIDEO_INFO_COMP_STRIDE (&self->info, 0);
+
+  if (!vbi_raw_video_image (buf, GST_VIDEO_INFO_COMP_STRIDE (&self->info,
+              0) * 2, &self->sp, 0, 0, 0, 0x000000FF, 0, sliced, 2)) {
+    GST_ERROR_OBJECT (filter, "Failed to encode CC data");
+    goto done;
+  }
+
+  ret = GST_FLOW_OK;
+
+done:
+  return ret;
+}
diff --git a/ext/closedcaption/gstline21enc.h b/ext/closedcaption/gstline21enc.h
new file mode 100644
index 000000000..ac89f2cd5
--- /dev/null
+++ b/ext/closedcaption/gstline21enc.h
@@ -0,0 +1,61 @@
+/*
+ * GStreamer
+ * Copyright (C) 2019 Mathieu Duponchelle <mathieu@centricular.com>
+ *
+ * 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.
+ */
+
+#ifndef __GST_LINE21ENCODER_H__
+#define __GST_LINE21ENCODER_H__
+
+#include <gst/gst.h>
+#include <gst/video/video.h>
+#include <gst/video/video-anc.h>
+#include "io-sim.h"
+
+G_BEGIN_DECLS
+#define GST_TYPE_LINE21ENCODER \
+  (gst_line_21_encoder_get_type())
+#define GST_LINE21ENCODER(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_LINE21ENCODER,GstLine21Encoder))
+#define GST_LINE21ENCODER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_LINE21ENCODER,GstLine21EncoderClass))
+#define GST_IS_LINE21ENCODER(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_LINE21ENCODER))
+#define GST_IS_LINE21ENCODER_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_LINE21ENCODER))
+
+typedef struct _GstLine21Encoder GstLine21Encoder;
+typedef struct _GstLine21EncoderClass GstLine21EncoderClass;
+
+struct _GstLine21Encoder
+{
+  GstVideoFilter parent;
+
+  vbi_sampling_par sp;
+
+  GstVideoInfo info;
+};
+
+struct _GstLine21EncoderClass
+{
+  GstVideoFilterClass parent_class;
+};
+
+GType gst_line_21_encoder_get_type (void);
+
+G_END_DECLS
+#endif /* __GST_LINE21ENCODER_H__ */
diff --git a/ext/closedcaption/meson.build b/ext/closedcaption/meson.build
index c5c971b2e..50329df25 100644
--- a/ext/closedcaption/meson.build
+++ b/ext/closedcaption/meson.build
@@ -12,11 +12,12 @@ zvbi_sources = [
 if pangocairo_dep.found()
   gstclosedcaption = library('gstclosedcaption',
     'gstcccombiner.c', 'gstccextractor.c', 'gstccconverter.c', 'gstclosedcaption.c',
-    'gstline21dec.c', 'gstcea708decoder.c', 'gstceaccoverlay.c', zvbi_sources,
+    'gstline21dec.c', 'gstcea708decoder.c', 'gstceaccoverlay.c', 'gstline21enc.c',
+    zvbi_sources,
     c_args : gst_plugins_bad_args,
     link_args : noseh_link_args,
     include_directories : [configinc],
-    dependencies : [gstvideo_dep, gstbase_dep, gst_dep, pangocairo_dep],
+    dependencies : [gstvideo_dep, gstbase_dep, gst_dep, pangocairo_dep, libm],
     install : true,
     install_dir : plugins_install_dir,
   )