Add 12 bit YUV to 10 bit RGB

Bug: libyuv:843
Change-Id: I0104c8fcaeed09e83d2fd654c6a5e7d41bcb74cf
Reviewed-on: https://chromium-review.googlesource.com/c/libyuv/libyuv/+/2727775
Reviewed-by: Frank Barchard <fbarchard@chromium.org>
Reviewed-by: Wan-Teh Chang <wtc@google.com>

1 files changed, 24 insertions, 1 deletions

diff --git a/docs/formats.md b/docs/formats.md
index a29ed5c3..5fc19d45 100644
--- a/docs/formats.md
+++ b/docs/formats.md
@@ -4,7 +4,9 @@ Formats (FOURCC) supported by libyuv are detailed here.
 
 # Core Formats
 
-There are 2 core formats supported by libyuv - I420 and ARGB.  All YUV formats can be converted to/from I420.  All RGB formats can be converted to/from ARGB.
+There are 2 core formats supported by libyuv - I420 and ARGB.
+  All YUV formats can be converted to/from I420.
+  All RGB formats can be converted to/from ARGB.
 
 Filtering functions such as scaling and planar functions work on I420 and/or ARGB.
 
@@ -109,6 +111,27 @@ The following is extracted from video_common.h as a complete list of formats sup
         I444, NV24 and NV42 are full width, full height
         I400 and J400 have no chroma channel.
 
+# Color space
+      The YUV formats start with a letter to specify the color space. e.g. I420
+        I = BT.601 limited range
+        J = BT.601 full range     (J = JPEG that uses this)
+        H = BT.709 limited range  (H for HD)
+        F = BT.709 full range     (F for Full range)
+        U = BT.2020 limited range (U for UHD)
+        V = BT.2020 full range
+        For YUV to RGB conversions, a matrix can be passed.  See also convert_argh.h
+
+# HDR formats
+      Planar formats with 10 or 12 bits use the following fourcc:
+        I010, I012, P010, P012 are half width, half height
+        I210, I212, P210, P212 are half width, full height
+        I410, I412, P410, P412 are full width, full height
+      where
+        I is the color space (see above) and 3 planes: Y, U and V.
+        P is a biplanar format, similar to NV12 but 16 bits, with the valid bits in the high bits.  There is a Y plane and a UV plane.
+        0, 2 or 4 is the last digit of subsampling: 4:2:0, 4:2:2, or 4:4:4
+        10 or 12 is the bits per channel.  The bits are in the low bits of a 16 bit channel.
+
 # The ARGB FOURCC
 
 There are 4 ARGB layouts - ARGB, BGRA, ABGR and RGBA.  ARGB is most common by far, used for screen formats, and windows webcam drivers.