Merge pull request #16626 from firebladed:firebladed-v4l2_pix_fmt_y12

V4L2: Add V4L2_PIX_FMT_Y12 (12 bit grey) support

modules/videoio/src/cap_v4l.cpp

@@ -262,6 +262,10 @@ make & enjoy!
 #define V4L2_PIX_FMT_Y10 v4l2_fourcc('Y', '1', '0', ' ')
 #endif
 
+#ifndef V4L2_PIX_FMT_Y12
+#define V4L2_PIX_FMT_Y12 v4l2_fourcc('Y', '1', '2', ' ')
+#endif
+
 /* Defaults - If your board can do better, set it here.  Set for the most common type inputs. */
 #define DEFAULT_V4L_WIDTH  640
 #define DEFAULT_V4L_HEIGHT 480
@@ -561,6 +565,7 @@ bool CvCaptureCAM_V4L::autosetup_capture_mode_v4l2()
             V4L2_PIX_FMT_JPEG,
 #endif
             V4L2_PIX_FMT_Y16,
+            V4L2_PIX_FMT_Y12,
             V4L2_PIX_FMT_Y10,
             V4L2_PIX_FMT_GREY,
     };
@@ -654,6 +659,7 @@ void CvCaptureCAM_V4L::v4l2_create_frame()
             size.height = size.height * 3 / 2; // "1.5" channels
             break;
         case V4L2_PIX_FMT_Y16:
+        case V4L2_PIX_FMT_Y12:
         case V4L2_PIX_FMT_Y10:
             depth = IPL_DEPTH_16U;
             /* fallthru */
@@ -1578,6 +1584,13 @@ void CvCaptureCAM_V4L::convertToRgb(const Buffer &currentBuffer)
         cv::cvtColor(temp, destination, COLOR_GRAY2BGR);
         return;
     }
+    case V4L2_PIX_FMT_Y12:
+    {
+        cv::Mat temp(imageSize, CV_8UC1, buffers[MAX_V4L_BUFFERS].start);
+        cv::Mat(imageSize, CV_16UC1, currentBuffer.start).convertTo(temp, CV_8U, 1.0 / 16);
+        cv::cvtColor(temp, destination, COLOR_GRAY2BGR);
+        return;
+    }
     case V4L2_PIX_FMT_Y10:
     {
         cv::Mat temp(imageSize, CV_8UC1, buffers[MAX_V4L_BUFFERS].start);