line21enc: heavily constrain video height

We can only determine a correct placement for the CC line
with:

* height == 525 (standard NTSC, line 21 / 22)
* height == 486 (NTSC usable lines + 6 lines for VBI, line 1 / 2)

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1554>

diff --git a/docs/plugins/gst_plugins_cache.json b/docs/plugins/gst_plugins_cache.json
index ecda85b..e69a334 100644 (file)
--- a/docs/plugins/gst_plugins_cache.json
+++ b/docs/plugins/gst_plugins_cache.json
@@ -3426,12 +3426,12 @@
                 "long-name": "Line 21 CC Encoder",
                 "pad-templates": {
                     "sink": {
-                        "caps": "video/x-raw:\n         format: { I420, YUY2, YVYU, UYVY, VYUY }\n          width: 720\n         height: [ 23, 2147483647 ]\n interlace-mode: interleaved\n",
+                        "caps": "video/x-raw:\n         format: { I420, YUY2, YVYU, UYVY, VYUY }\n          width: 720\n         height: { (int)525, (int)486 }\n interlace-mode: interleaved\n",
                         "direction": "sink",
                         "presence": "always"
                     },
                     "src": {
-                        "caps": "video/x-raw:\n         format: { I420, YUY2, YVYU, UYVY, VYUY }\n          width: 720\n         height: [ 23, 2147483647 ]\n interlace-mode: interleaved\n",
+                        "caps": "video/x-raw:\n         format: { I420, YUY2, YVYU, UYVY, VYUY }\n          width: 720\n         height: { (int)525, (int)486 }\n interlace-mode: interleaved\n",
                         "direction": "src",
                         "presence": "always"
                     }

diff --git a/ext/closedcaption/gstline21enc.c b/ext/closedcaption/gstline21enc.c
index 424b625..6c9d13c 100644 (file)
--- a/ext/closedcaption/gstline21enc.c
+++ b/ext/closedcaption/gstline21enc.c
@@ -39,7 +39,8 @@
 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"
+/* FIXME: add and test support for PAL resolutions */
+#define CAPS "video/x-raw, format={ I420, YUY2, YVYU, UYVY, VYUY }, width=(int)720, height=(int){ 525, 486 }, interlace-mode=interleaved"
 
 static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
@@ -370,6 +371,7 @@ gst_line_21_encoder_transform_ip (GstVideoFilter * filter,
   vbi_sliced sliced[2];
   gpointer iter = NULL;
   GstFlowReturn ret = GST_FLOW_ERROR;
+  guint offset;
 
   sliced[0].id = VBI_SLICED_CAPTION_525_F1;
   sliced[0].line = self->sp.start[0];
@@ -447,9 +449,14 @@ gst_line_21_encoder_transform_ip (GstVideoFilter * filter,
   if (cc_meta)
     gst_buffer_remove_meta (frame->buffer, (GstMeta *) cc_meta);
 
+  /* When dealing with standard NTSC resolution, field 1 goes at line 21,
+   * when dealing with a reduced height the image has 3 VBI lines at the
+   * top and 3 at the bottom, and field 1 goes at line 1 */
+  offset = self->info.height == 525 ? 21 : 1;
+
   buf =
       (guint8 *) GST_VIDEO_FRAME_PLANE_DATA (frame,
-      0) + 21 * GST_VIDEO_INFO_COMP_STRIDE (&self->info, 0);
+      0) + offset * 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)) {

diff --git a/tests/check/elements/line21.c b/tests/check/elements/line21.c
index 02547ec..2a507fa 100644 (file)
--- a/tests/check/elements/line21.c
+++ b/tests/check/elements/line21.c
@@ -33,12 +33,12 @@ GST_START_TEST (basic)
   GstVideoInfo info;
   GstVideoCaptionMeta *in_cc_meta, *out_cc_meta;
   guint i;
-  guint8 empty_data[] = { 0x90, 0x80, 0x80, 0x0, 0x80, 0x80 };
-  guint8 full_data[] = { 0x90, 0x42, 0x43, 0x0, 0x44, 0x45 };
+  guint8 empty_data[] = { 0x8c, 0x80, 0x80, 0x0, 0x80, 0x80 };
+  guint8 full_data[] = { 0x8c, 0x42, 0x43, 0x0, 0x44, 0x45 };
   GstCaps *caps = gst_caps_new_simple ("video/x-raw",
       "format", G_TYPE_STRING, "I420",
       "width", G_TYPE_INT, 720,
-      "height", G_TYPE_INT, 625,
+      "height", G_TYPE_INT, 525,
       "interlace-mode", G_TYPE_STRING, "interleaved",
       NULL);
 
@@ -62,7 +62,7 @@ GST_START_TEST (basic)
   fail_unless (out_cc_meta->size == 6);
 
   for (i = 0; i < out_cc_meta->size; i++)
-    fail_unless (out_cc_meta->data[i] == empty_data[i]);
+    fail_unless_equals_int (out_cc_meta->data[i], empty_data[i]);
 
   gst_buffer_unref (outbuf);