v4l2bufferpool: set buffer interlace flags when field is V4L2_FIELD_INTERLACED

If v4l2_buffer.field is V4L2_FIELD_INTERLACED, we set corresponding
GstVideoBuffer flags depending on the video standard.
According to V4L2 specification, M/NTSC transmits the bottom field
first, all other standards the top field first.

https://bugzilla.gnome.org/show_bug.cgi?id=737603

diff --git a/sys/v4l2/gstv4l2bufferpool.c b/sys/v4l2/gstv4l2bufferpool.c
index fa069a9..6445adb 100644 (file)
--- a/sys/v4l2/gstv4l2bufferpool.c
+++ b/sys/v4l2/gstv4l2bufferpool.c
@@ -1130,6 +1130,16 @@ gst_v4l2_buffer_pool_dqbuf (GstV4l2BufferPool * pool, GstBuffer ** buffer)
       GST_BUFFER_FLAG_SET (outbuf, GST_VIDEO_BUFFER_FLAG_INTERLACED);
       GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF);
       break;
+    case V4L2_FIELD_INTERLACED:
+      GST_BUFFER_FLAG_SET (outbuf, GST_VIDEO_BUFFER_FLAG_INTERLACED);
+      if (obj->tv_norm == V4L2_STD_NTSC_M ||
+          obj->tv_norm == V4L2_STD_NTSC_M_JP ||
+          obj->tv_norm == V4L2_STD_NTSC_M_KR) {
+        GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF);
+      } else {
+        GST_BUFFER_FLAG_SET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF);
+      }
+      break;
     default:
       GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_INTERLACED);
       GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF);