qroverlay: Rework basing it on overlaycomposition

The base class is now a bin which wraps the `overlaycomposition`
element and implements the `draw` signal.

This way we support all the video formats the GstVideoOverlayComposition
API supports and the blending code can be reused. It is also possible
to have the blending happen in the sinks now.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1829>

4 files changed, 171 insertions, 127 deletions

diff --git a/ext/qroverlay/gstbaseqroverlay.c b/ext/qroverlay/gstbaseqroverlay.c
index 3d0334b2b..0e647649d 100644
--- a/ext/qroverlay/gstbaseqroverlay.c
+++ b/ext/qroverlay/gstbaseqroverlay.c
@@ -62,26 +62,30 @@ struct _GstBaseQROverlayPrivate
   QRecLevel level;
   gfloat x_percent;
   gfloat y_percent;
+  GstElement *overlaycomposition;
+  GstVideoInfo info;
+  gboolean valid;
+
+  GstPad *sinkpad, *srcpad;
 };
 
 #define PRIV(s) gst_base_qr_overlay_get_instance_private (GST_BASE_QR_OVERLAY (s))
 
+#define OVERLAY_COMPOSITION_CAPS GST_VIDEO_CAPS_MAKE (GST_VIDEO_OVERLAY_COMPOSITION_BLEND_FORMATS)
+
+#define ALL_CAPS OVERLAY_COMPOSITION_CAPS ";" \
+    GST_VIDEO_CAPS_MAKE_WITH_FEATURES ("ANY", GST_VIDEO_FORMATS_ALL)
+
 static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw, "
-        "format = (string) { I420 }, "
-        "framerate = (fraction) [0, MAX], "
-        "width = (int) [ 16, MAX ], " "height = (int) [ 16, MAX ]")
+    GST_STATIC_CAPS (ALL_CAPS)
     );
 
 static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
-    GST_STATIC_CAPS ("video/x-raw, "
-        "format = (string) { I420 }, "
-        "framerate = (fraction) [0, MAX], "
-        "width = (int) [ 16, MAX ], " "height = (int) [ 16, MAX ]")
+    GST_STATIC_CAPS (ALL_CAPS)
     );
 
 #define DEFAULT_PROP_QUALITY    1
@@ -110,16 +114,132 @@ gst_qrcode_quality_get_type (void)
 
 #define gst_base_qr_overlay_parent_class parent_class
 G_DEFINE_TYPE_WITH_PRIVATE (GstBaseQROverlay, gst_base_qr_overlay,
-    GST_TYPE_VIDEO_FILTER);
+    GST_TYPE_BIN);
 
 static void gst_base_qr_overlay_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec);
 static void gst_base_qr_overlay_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec);
 
-static GstFlowReturn
-gst_base_qr_overlay_transform_frame_ip (GstVideoFilter * base,
-    GstVideoFrame * frame);
+static void
+gst_base_qr_overlay_caps_changed_cb (GstBaseQROverlay * self, GstCaps * caps,
+    gint window_width, gint window_height, GstElement * overlay)
+{
+  GstBaseQROverlayPrivate *priv = PRIV (self);
+
+  if (gst_video_info_from_caps (&priv->info, caps))
+    priv->valid = TRUE;
+  else
+    priv->valid = FALSE;
+}
+
+static GstVideoOverlayComposition *
+draw_overlay (GstBaseQROverlay * self, QRcode * qrcode)
+{
+  guint8 *qr_data, *pixels;
+  gint stride, pstride, y, x, yy, square_size;
+  gsize offset, line_offset;
+  GstVideoInfo info;
+  GstVideoOverlayRectangle *rect;
+  GstVideoOverlayComposition *comp;
+  GstBuffer *buf;
+  GstBaseQROverlayPrivate *priv = PRIV (self);
+
+  gst_video_info_init (&info);
+
+  square_size = (qrcode->width + 4 * 2) * priv->qrcode_size;
+  gst_video_info_set_format (&info, GST_VIDEO_FORMAT_ARGB, square_size,
+      square_size);
+
+  pixels = g_malloc ((size_t) info.size);
+  stride = info.stride[0];
+  pstride = info.finfo->pixel_stride[0];
+
+  /* White background */
+  for (y = 0; y < info.height; y++)
+    memset (&pixels[y * stride], 0xff, stride);
+
+  /* Draw the black QR code blocks with 4px white space around it
+   * on top */
+  line_offset = 4 * priv->qrcode_size * stride;
+  qr_data = qrcode->data;
+  for (y = 0; y < qrcode->width; y++) {
+    for (x = 0; x < (qrcode->width); x++) {
+      for (yy = 0; yy < priv->qrcode_size * pstride; yy += pstride) {
+        if (!(*qr_data & 1))
+          continue;
+
+        offset =
+            (((line_offset + (stride * (yy / pstride))) +
+                x * priv->qrcode_size * pstride)) +
+            (priv->qrcode_size * pstride) + (4 * priv->qrcode_size * pstride);
+
+        for (gint i = 0; i < priv->qrcode_size * pstride; i += pstride) {
+          pixels[offset + i] = 0x00;
+          pixels[offset + i + 1] = 0x00;
+          pixels[offset + i + 2] = 0x00;
+        }
+      }
+      qr_data++;
+    }
+    line_offset += (stride * priv->qrcode_size);
+  }
+
+  buf = gst_buffer_new_wrapped (pixels, info.size);
+  gst_buffer_add_video_meta (buf, GST_VIDEO_FRAME_FLAG_NONE,
+      GST_VIDEO_OVERLAY_COMPOSITION_FORMAT_RGB, info.width, info.height);
+
+  x = (int) (priv->info.width - square_size) * (priv->x_percent / 100);
+  x = GST_ROUND_DOWN_2 (x);
+  y = (int) (priv->info.height - square_size) * (priv->y_percent / 100);
+  y = GST_ROUND_DOWN_4 (y);
+
+  rect = gst_video_overlay_rectangle_new_raw (buf, x, y,
+      info.width, info.height, GST_VIDEO_OVERLAY_FORMAT_FLAG_NONE);
+  comp = gst_video_overlay_composition_new (rect);
+  gst_video_overlay_rectangle_unref (rect);
+
+  return comp;
+}
+
+static GstVideoOverlayComposition *
+gst_base_qr_overlay_draw_cb (GstBaseQROverlay * self, GstSample * sample,
+    GstElement * _)
+{
+  GstBaseQROverlayPrivate *priv = PRIV (self);
+  QRcode *qrcode;
+  gchar *content;
+  GstVideoOverlayComposition *overlay = NULL;
+  GstBuffer *buffer = gst_sample_get_buffer (sample);
+  GstSegment *segment = gst_sample_get_segment (sample);
+  GstClockTime rtime = gst_segment_to_running_time (segment, GST_FORMAT_TIME,
+      GST_BUFFER_PTS (buffer));
+
+  if (!priv->valid) {
+    GST_ERROR_OBJECT (self, "Trying to draw before negotiation?");
+
+    return NULL;
+  }
+
+  if (GST_CLOCK_TIME_IS_VALID (rtime))
+    gst_object_sync_values (GST_OBJECT (self), rtime);
+
+  content =
+      GST_BASE_QR_OVERLAY_GET_CLASS (self)->get_content (GST_BASE_QR_OVERLAY
+      (self), buffer, &priv->info);
+  GST_INFO_OBJECT (self, "String will be encoded : %s", content);
+  qrcode = QRcode_encodeString (content, 0, priv->qrcode_quality, QR_MODE_8, 0);
+
+  if (qrcode) {
+    GST_DEBUG_OBJECT (self, "String encoded");
+    overlay = draw_overlay (GST_BASE_QR_OVERLAY (self), qrcode);
+  } else {
+    GST_WARNING_OBJECT (self, "Could not encode content: %s", content);
+  }
+  g_free (content);
+
+  return overlay;
+}
 
 /* GObject vmethod implementations */
 
@@ -136,6 +256,9 @@ gst_base_qr_overlay_class_init (GstBaseQROverlayClass * klass)
   gobject_class->set_property = gst_base_qr_overlay_set_property;
   gobject_class->get_property = gst_base_qr_overlay_get_property;
 
+  GST_DEBUG_CATEGORY_INIT (gst_base_qr_overlay_debug, "qroverlay", 0,
+      "Qrcode overlay base class");
+
   g_object_class_install_property (gobject_class,
       PROP_X_AXIS, g_param_spec_float ("x",
           "X position (in percent of the width)",
@@ -164,9 +287,6 @@ gst_base_qr_overlay_class_init (GstBaseQROverlayClass * klass)
       gst_static_pad_template_get (&sink_template));
 
   gst_type_mark_as_plugin_api (GST_TYPE_QRCODE_QUALITY, 0);
-
-  GST_VIDEO_FILTER_CLASS (klass)->transform_frame_ip =
-      GST_DEBUG_FUNCPTR (gst_base_qr_overlay_transform_frame_ip);
   gst_type_mark_as_plugin_api (GST_TYPE_QRCODE_QUALITY, 0);
 }
 
@@ -174,15 +294,39 @@ gst_base_qr_overlay_class_init (GstBaseQROverlayClass * klass)
  * initialize instance structure
  */
 static void
-gst_base_qr_overlay_init (GstBaseQROverlay * filter)
+gst_base_qr_overlay_init (GstBaseQROverlay * self)
 {
-  GstBaseQROverlayPrivate *priv = PRIV (filter);
+  GstBaseQROverlayPrivate *priv = PRIV (self);
 
   priv->x_percent = 50.0;
   priv->y_percent = 50.0;
   priv->qrcode_quality = DEFAULT_PROP_QUALITY;
   priv->span_frame = 0;
   priv->qrcode_size = DEFAULT_PROP_PIXEL_SIZE;
+  priv->overlaycomposition =
+      gst_element_factory_make ("overlaycomposition", NULL);
+  gst_video_info_init (&priv->info);
+
+  if (priv->overlaycomposition) {
+    GstPadTemplate *sink_tmpl = gst_static_pad_template_get (&sink_template);
+    GstPadTemplate *src_tmpl = gst_static_pad_template_get (&src_template);
+
+    gst_bin_add (GST_BIN (self), priv->overlaycomposition);
+
+    gst_element_add_pad (GST_ELEMENT_CAST (self),
+        gst_ghost_pad_new_from_template ("sink",
+            priv->overlaycomposition->sinkpads->data, sink_tmpl));
+    gst_element_add_pad (GST_ELEMENT_CAST (self),
+        gst_ghost_pad_new_from_template ("src",
+            priv->overlaycomposition->srcpads->data, src_tmpl));
+    gst_object_unref (sink_tmpl);
+    gst_object_unref (src_tmpl);
+
+    g_signal_connect_swapped (priv->overlaycomposition, "draw",
+        G_CALLBACK (gst_base_qr_overlay_draw_cb), self);
+    g_signal_connect_swapped (priv->overlaycomposition, "caps-changed",
+        G_CALLBACK (gst_base_qr_overlay_caps_changed_cb), self);
+  }
 }
 
 static void
@@ -234,103 +378,3 @@ gst_base_qr_overlay_get_property (GObject * object, guint prop_id,
       break;
   }
 }
-
-static void
-overlay_qr_in_frame (GstBaseQROverlay * filter, QRcode * qrcode,
-    GstVideoFrame * frame)
-{
-  GstBaseQROverlayPrivate *priv = PRIV (filter);
-  guchar *source_data;
-  gint32 k, y, x, yy, square_size, line = 0;
-  int x1, x2, y1, y2;
-  guint8 *d;
-  gint stride;
-
-  square_size = (qrcode->width + 4 * 2) * priv->qrcode_size;
-  /* White bg */
-  x1 = (int) (GST_VIDEO_FRAME_WIDTH (frame) -
-      square_size) * (priv->x_percent / 100);
-  x1 = GST_ROUND_DOWN_2 (x1);
-  x2 = x1 + square_size;
-  y1 = (int) (GST_VIDEO_FRAME_HEIGHT (frame) -
-      square_size) * (priv->y_percent / 100);
-  y1 = GST_ROUND_DOWN_4 (y1);
-  y2 = y1 + square_size;
-
-  d = GST_VIDEO_FRAME_PLANE_DATA (frame, 0);
-  stride = GST_VIDEO_FRAME_PLANE_STRIDE (frame, 0);
-
-  /* Start drawing the white luma plane */
-  for (y = y1; y < y2; y++) {
-    for (x = x1; x < x2; x += square_size)
-      memset (&d[y * stride + x], 0xff, square_size);
-  }
-
-  /* Draw the black QR code blocks with 4px white space around it
-   * on top */
-  line += 4 * priv->qrcode_size * stride;
-  source_data = qrcode->data;
-  for (y = 0; y < qrcode->width; y++) {
-    for (x = 0; x < (qrcode->width); x++) {
-      for (yy = 0; yy < priv->qrcode_size; yy++) {
-        k = ((((line + (4 * priv->qrcode_size))) + stride * yy +
-                x * priv->qrcode_size) + x1) + (y1 * stride);
-        if (*source_data & 1) {
-          memset (d + k, 0, priv->qrcode_size);
-        }
-      }
-      source_data++;
-    }
-    line += (stride * priv->qrcode_size);
-  }
-
-  /* Set Chrominance planes */
-  x1 /= 2;
-  x2 /= 2;
-  y1 /= 2;
-  y2 /= 2;
-  stride = GST_VIDEO_FRAME_PLANE_STRIDE (frame, 1);
-  for (y = y1; y < y2; y++) {
-    for (x = x1; x < x2; x += (x2 - x1)) {
-      d = GST_VIDEO_FRAME_PLANE_DATA (frame, 1);
-      memset (&d[y * stride + x], 128, (x2 - x1));
-      d = GST_VIDEO_FRAME_PLANE_DATA (frame, 2);
-      memset (&d[y * stride + x], 128, (x2 - x1));
-    }
-  }
-
-  QRcode_free (qrcode);
-}
-
-/* GstBaseTransform vmethod implementations */
-/* this function does the actual processing
- */
-static GstFlowReturn
-gst_base_qr_overlay_transform_frame_ip (GstVideoFilter * base,
-    GstVideoFrame * frame)
-{
-  GstBaseQROverlayPrivate *priv = PRIV (base);
-  QRcode *qrcode;
-  gchar *content;
-  GstClockTime rtime =
-      gst_segment_to_running_time (&GST_BASE_TRANSFORM (base)->segment,
-      GST_FORMAT_TIME, GST_BUFFER_PTS (frame->buffer));
-
-  if (GST_CLOCK_TIME_IS_VALID (rtime))
-    gst_object_sync_values (GST_OBJECT (base), rtime);
-
-  content =
-      GST_BASE_QR_OVERLAY_GET_CLASS (base)->get_content (GST_BASE_QR_OVERLAY
-      (base), frame);
-  GST_INFO_OBJECT (base, "String will be encoded : %s", content);
-  qrcode = QRcode_encodeString (content, 0, priv->qrcode_quality, QR_MODE_8, 0);
-  if (qrcode) {
-    GST_DEBUG_OBJECT (base, "String encoded");
-    overlay_qr_in_frame (GST_BASE_QR_OVERLAY (base), qrcode, frame);
-  } else {
-    GST_WARNING_OBJECT (base, "Could not encode content: %s", content);
-  }
-  g_free (content);
-
-  return GST_FLOW_OK;
-}
diff --git a/ext/qroverlay/gstbaseqroverlay.h b/ext/qroverlay/gstbaseqroverlay.h
index 478cbe443..4fcb16a52 100644
--- a/ext/qroverlay/gstbaseqroverlay.h
+++ b/ext/qroverlay/gstbaseqroverlay.h
@@ -32,9 +32,9 @@ G_DECLARE_DERIVABLE_TYPE (GstBaseQROverlay, gst_base_qr_overlay, GST, BASE_QR_OV
 
 struct _GstBaseQROverlayClass
 {
-  GstVideoFilterClass parent;
+  GstBinClass parent;
 
-  gchar* (*get_content) (GstBaseQROverlay *self, GstVideoFrame *frame);
+  gchar* (*get_content) (GstBaseQROverlay *self, GstBuffer *buf, GstVideoInfo *info);
 };
 
 G_END_DECLS
diff --git a/ext/qroverlay/gstdebugqroverlay.c b/ext/qroverlay/gstdebugqroverlay.c
index 69fde6bee..bcd73bceb 100644
--- a/ext/qroverlay/gstdebugqroverlay.c
+++ b/ext/qroverlay/gstdebugqroverlay.c
@@ -59,8 +59,8 @@
 GST_DEBUG_CATEGORY_STATIC (gst_debug_qr_overlay_debug);
 #define GST_CAT_DEFAULT gst_debug_qr_overlay_debug
 
-static gchar *get_qrcode_content (GstBaseQROverlay * filter,
-    GstVideoFrame * frame);
+static gchar *get_qrcode_content (GstBaseQROverlay * base, GstBuffer * buf,
+    GstVideoInfo * info);
 
 enum
 {
@@ -231,14 +231,13 @@ gst_debug_qr_overlay_get_property (GObject * object, guint prop_id,
 }
 
 static gchar *
-get_qrcode_content (GstBaseQROverlay * base, GstVideoFrame * frame)
+get_qrcode_content (GstBaseQROverlay * base, GstBuffer * buf,
+    GstVideoInfo * info)
 {
   GstDebugQROverlay *filter = GST_DEBUG_QR_OVERLAY (base);
-  GstBuffer *buf = frame->buffer;
   GString *res = g_string_new (NULL);
   JsonGenerator *jgen;
-  gchar *framerate_string =
-      g_strdup_printf ("%d/%d", frame->info.fps_n, frame->info.fps_d);
+  gchar *framerate_string = g_strdup_printf ("%d/%d", info->fps_n, info->fps_d);
 
   JsonObject *jobj = json_object_new ();
   JsonNode *root = json_node_new (JSON_NODE_OBJECT);
diff --git a/ext/qroverlay/gstqroverlay.c b/ext/qroverlay/gstqroverlay.c
index ca9cbba0b..a55f70e84 100644
--- a/ext/qroverlay/gstqroverlay.c
+++ b/ext/qroverlay/gstqroverlay.c
@@ -68,9 +68,10 @@ struct _GstQROverlay
 G_DEFINE_TYPE (GstQROverlay, gst_qr_overlay, GST_TYPE_BASE_QR_OVERLAY);
 
 static gchar *
-get_qrcode_content (GstBaseQROverlay * filter, GstVideoFrame * frame)
+get_qrcode_content (GstBaseQROverlay * self, GstBuffer * buf,
+    GstVideoInfo * info)
 {
-  return g_strdup (GST_QR_OVERLAY (filter)->data);
+  return g_strdup (GST_QR_OVERLAY (self)->data);
 }
 
 static void