[media] videodev2.h: add support for transfer functions
In the past the transfer function was implied by the colorspace. However,
it is an independent entity in its own right. Add support for explicitly
choosing the transfer function.
This change will allow us to represent linear RGB (as is used by openGL), and
it will make it easier to work with decoded video material since most codecs
store the transfer function as a separate property as well.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index 003a912..3d5fc72 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -240,6 +240,42 @@
((is_sdtv) ? V4L2_COLORSPACE_SMPTE170M : \
((is_hdtv) ? V4L2_COLORSPACE_REC709 : V4L2_COLORSPACE_SRGB))
+enum v4l2_xfer_func {
+ /*
+ * Mapping of V4L2_XFER_FUNC_DEFAULT to actual transfer functions
+ * for the various colorspaces:
+ *
+ * V4L2_COLORSPACE_SMPTE170M, V4L2_COLORSPACE_470_SYSTEM_M,
+ * V4L2_COLORSPACE_470_SYSTEM_BG, V4L2_COLORSPACE_REC709 and
+ * V4L2_COLORSPACE_BT2020: V4L2_XFER_FUNC_709
+ *
+ * V4L2_COLORSPACE_SRGB, V4L2_COLORSPACE_JPEG: V4L2_XFER_FUNC_SRGB
+ *
+ * V4L2_COLORSPACE_ADOBERGB: V4L2_XFER_FUNC_ADOBERGB
+ *
+ * V4L2_COLORSPACE_SMPTE240M: V4L2_XFER_FUNC_SMPTE240M
+ *
+ * V4L2_COLORSPACE_RAW: V4L2_XFER_FUNC_NONE
+ */
+ V4L2_XFER_FUNC_DEFAULT = 0,
+ V4L2_XFER_FUNC_709 = 1,
+ V4L2_XFER_FUNC_SRGB = 2,
+ V4L2_XFER_FUNC_ADOBERGB = 3,
+ V4L2_XFER_FUNC_SMPTE240M = 4,
+ V4L2_XFER_FUNC_NONE = 5,
+};
+
+/*
+ * Determine how XFER_FUNC_DEFAULT should map to a proper transfer function.
+ * This depends on the colorspace.
+ */
+#define V4L2_MAP_XFER_FUNC_DEFAULT(colsp) \
+ ((colsp) == V4L2_XFER_FUNC_ADOBERGB ? V4L2_XFER_FUNC_ADOBERGB : \
+ ((colsp) == V4L2_COLORSPACE_SMPTE240M ? V4L2_XFER_FUNC_SMPTE240M : \
+ ((colsp) == V4L2_COLORSPACE_RAW ? V4L2_XFER_FUNC_NONE : \
+ ((colsp) == V4L2_COLORSPACE_SRGB || (colsp) == V4L2_COLORSPACE_JPEG ? \
+ V4L2_XFER_FUNC_SRGB : V4L2_XFER_FUNC_709))))
+
enum v4l2_ycbcr_encoding {
/*
* Mapping of V4L2_YCBCR_ENC_DEFAULT to actual encodings for the
@@ -409,6 +445,7 @@
__u32 flags; /* format flags (V4L2_PIX_FMT_FLAG_*) */
__u32 ycbcr_enc; /* enum v4l2_ycbcr_encoding */
__u32 quantization; /* enum v4l2_quantization */
+ __u32 xfer_func; /* enum v4l2_xfer_func */
};
/* Pixel format FOURCC depth Description */
@@ -1907,6 +1944,7 @@
* @flags: format flags (V4L2_PIX_FMT_FLAG_*)
* @ycbcr_enc: enum v4l2_ycbcr_encoding, Y'CbCr encoding
* @quantization: enum v4l2_quantization, colorspace quantization
+ * @xfer_func: enum v4l2_xfer_func, colorspace transfer function
*/
struct v4l2_pix_format_mplane {
__u32 width;
@@ -1920,7 +1958,8 @@
__u8 flags;
__u8 ycbcr_enc;
__u8 quantization;
- __u8 reserved[8];
+ __u8 xfer_func;
+ __u8 reserved[7];
} __attribute__ ((packed));
/**