ccconverter: fix cdp->cea608-raw field 1 60fps conversion

There was a potential busy loop occuring because when we were taking
data from the internal ccbuffer, we were not resetting which field had
written data.  This would mean that the next time data was retrieved
from ccbuffer, it was always from field 0 and never from field 1.

This only affects usage of cc_buffer_take_separated() which is only used
by cdp->raw cea608.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6423>

subprojects/gst-plugins-bad/ext/closedcaption/ccutils.c

@@ -784,7 +784,7 @@ cc_buffer_get_out_sizes (CCBuffer * buf, const struct cdp_fps_entry *fps_entry,
   *field1_padding = 0;
   *field2_padding = 0;
 
-  wrote_first = !buf->last_cea608_written_was_field1;
+  wrote_first = buf->last_cea608_written_was_field1;
   /* try to push data into the packets.  Anything 'extra' will be
    * stored for later */
   while (TRUE) {
@@ -795,7 +795,7 @@ cc_buffer_get_out_sizes (CCBuffer * buf, const struct cdp_fps_entry *fps_entry,
     if (avail_1 + avail_2 >= 2 * fps_entry->max_cea608_count)
       break;
 
-    if (wrote_first) {
+    if (!wrote_first) {
       if (extra_cea608_1 > 0) {
         extra_cea608_1 -= 2;
         g_assert_cmpint (extra_cea608_1, >=, 0);
@@ -821,7 +821,7 @@ cc_buffer_get_out_sizes (CCBuffer * buf, const struct cdp_fps_entry *fps_entry,
        * requested to start with field2 */
       *field2_padding += 2;
     }
-    wrote_first = TRUE;
+    wrote_first = FALSE;
   }
 
   // don't write padding if not requested
@@ -868,11 +868,13 @@ cc_buffer_take_separated (CCBuffer * buf,
       memcpy (cea608_1, buf->cea608_1->data, write_cea608_1_size);
       memset (&cea608_1[write_cea608_1_size], 0x80, field1_padding);
       if (write_cea608_1_size == 0) {
-        buf->field1_padding_written_count += write_cea608_1_size / 2;
+        buf->field1_padding_written_count += field1_padding / 2;
       } else {
         buf->field1_padding_written_count = 0;
       }
       *cea608_1_len = write_cea608_1_size + field1_padding;
+      if (*cea608_1_len > 0)
+        buf->last_cea608_written_was_field1 = TRUE;
     } else {
       *cea608_1_len = 0;
     }
@@ -886,11 +888,13 @@ cc_buffer_take_separated (CCBuffer * buf,
       memcpy (cea608_2, buf->cea608_2->data, write_cea608_2_size);
       memset (&cea608_2[write_cea608_2_size], 0x80, field2_padding);
       if (write_cea608_2_size == 0) {
-        buf->field2_padding_written_count += write_cea608_2_size / 2;
+        buf->field2_padding_written_count += field2_padding / 2;
       } else {
         buf->field2_padding_written_count = 0;
       }
       *cea608_2_len = write_cea608_2_size + field2_padding;
+      if (*cea608_2_len > 0)
+        buf->last_cea608_written_was_field1 = FALSE;
     } else {
       *cea608_2_len = 0;
     }

subprojects/gst-plugins-bad/ext/closedcaption/gstccconverter.c

@@ -1255,11 +1255,15 @@ convert_cea708_cdp_cea608_raw (GstCCConverter * self, GstBuffer * inbuf,
   gst_buffer_map (outbuf, &out, GST_MAP_WRITE);
   cea608_len = out.size;
   if (self->out_field == 0) {
+    guint8 unused_field[MAX_CEA608_LEN];
+    guint unused_len = MAX_CEA608_LEN;
     cc_buffer_take_separated (self->cc_buffer, out_fps_entry, out.data,
-        &cea608_len, NULL, 0, NULL, 0);
+        &cea608_len, unused_field, &unused_len, NULL, 0);
   } else {
-    cc_buffer_take_separated (self->cc_buffer, out_fps_entry, NULL, 0, out.data,
+    guint8 unused_field[MAX_CEA608_LEN];
-        &cea608_len, NULL, 0);
+    guint unused_len = MAX_CEA608_LEN;
+    cc_buffer_take_separated (self->cc_buffer, out_fps_entry, unused_field,
+        &unused_len, out.data, &cea608_len, NULL, 0);
   }
   gst_buffer_unmap (outbuf, &out);
   self->output_frames++;

subprojects/gst-plugins-bad/tests/check/elements/ccconverter.c

@@ -1285,6 +1285,34 @@ GST_START_TEST (convert_cea608_raw_field1_cea708_cdp_60fps)
 
 GST_END_TEST;
 
+GST_START_TEST (convert_cea708_cdp_cea608_raw_field_one_60fps)
+{
+  const guint8 in1[] =
+      { 0x96, 0x69, 0x2b, 0x8f, 0x43, 0x00, 0x00, 0x72, 0xea, 0xfc, 0x80, 0x80,
+    0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00,
+    0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00,
+    0xfa, 0x00, 0x00, 0x74, 0x00, 0x00, 0x6e,
+  };
+  const guint8 in2[] =
+      { 0x96, 0x69, 0x2b, 0x8f, 0x43, 0x00, 0x01, 0x72, 0xea, 0xfd, 0x81, 0x82,
+    0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00,
+    0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00, 0xfa, 0x00, 0x00,
+    0xfa, 0x00, 0x00, 0x74, 0x00, 0x01, 0x68,
+  };
+  const guint8 *in[] = { in1, in2 };
+  guint in_len[] = { sizeof (in1), sizeof (in2) };
+  const guint8 out1[] = { 0x81, 0x82 };
+  const guint8 *out[] = { out1 };
+  guint out_len[] = { sizeof (out1) };
+  check_conversion_multiple (G_N_ELEMENTS (in_len), in, in_len,
+      G_N_ELEMENTS (out_len), out, out_len,
+      "closedcaption/x-cea-708,format=(string)cdp,framerate=60/1",
+      "closedcaption/x-cea-608,format=(string)raw,framerate=60/1,field=1", NULL,
+      NULL, 0);
+}
+
+GST_END_TEST;
+
 static Suite *
 ccextractor_suite (void)
 {
@@ -1330,6 +1358,7 @@ ccextractor_suite (void)
   tcase_add_test (tc, convert_cea608_s334_1a_cea608_raw_field_one);
   tcase_add_test (tc, convert_cea708_cc_data_cea608_raw_field_one);
   tcase_add_test (tc, convert_cea708_cdp_cea608_raw_field_one);
+  tcase_add_test (tc, convert_cea708_cdp_cea608_raw_field_one_60fps);
   tcase_add_test (tc, convert_cea608_raw_cea608_raw_field_one);
   tcase_add_test (tc, convert_cea608_raw_field1_cea708_cdp_60fps);