media: doc: pixfmt-yuv: Move all packed YUV formats to common file

The pixfmt-packed-yuv.rst file documents packed YUV 4:4:4 formats, but
is titled generically as "Packed YUV formats". 4:2:2 and 4:1:1 packed
YUV formats are documented in separate files, which can be confusing.

Group all packed YUV formats in pixfmt-packed-yuv.rst, which allows
documenting the 4:2:2 formats in a more concise way.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

1 files changed, 140 insertions, 7 deletions

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
index 84262208dd1c..8ed1a6aff3a6 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-packed-yuv.rst
@@ -6,12 +6,16 @@
 Packed YUV formats
 ******************
 
-Description
-===========
+Similarly to the packed RGB formats, the packed YUV formats store the Y, Cb and
+Cr components consecutively in memory. They may apply subsampling to the chroma
+components and thus differ in how they interlave the three components.
 
-Similar to the packed RGB formats these formats store the Y, Cb and Cr
-component of each pixel in one 16 or 32 bit word.
 
+4:4:4 Subsampling
+=================
+
+These formats do not subsample the chroma components and store each pixels as a
+full triplet of Y, Cb and Cr values.
 
 .. raw:: latex
 
@@ -19,11 +23,9 @@ component of each pixel in one 16 or 32 bit word.
     \tiny
     \setlength{\tabcolsep}{2pt}
 
-.. _packed-yuv-formats:
-
 .. tabularcolumns:: |p{2.5cm}|p{0.69cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|p{0.31cm}|
 
-.. flat-table:: Packed YUV Image Formats
+.. flat-table:: Packed YUV 4:4:4 Image Formats
     :header-rows:  2
     :stub-columns: 0
 
@@ -371,3 +373,134 @@ component of each pixel in one 16 or 32 bit word.
        expected to contain a meaningful value that can be used by drivers
        and applications. And, the formats XYUV32 and VUYX32 contain undefined
        alpha values that must be ignored by all applications and drivers.
+
+
+4:2:2 Subsampling
+=================
+
+These formats, commonly referred to as YUYV or YUY2, subsample the chroma
+components horizontally by 2, storing 2 pixels in 4 bytes.
+
+.. flat-table:: Packed YUV 4:2:2 Formats
+    :header-rows: 1
+    :stub-columns: 0
+
+    * - Identifier
+      - Code
+      - Byte 0
+      - Byte 1
+      - Byte 2
+      - Byte 3
+      - Byte 4
+      - Byte 5
+      - Byte 6
+      - Byte 7
+    * .. _V4L2-PIX-FMT-UYVY:
+
+      - ``V4L2_PIX_FMT_UYVY``
+      - 'UYVY'
+
+      - Cb\ :sub:`0`
+      - Y'\ :sub:`0`
+      - Cr\ :sub:`0`
+      - Y'\ :sub:`1`
+      - Cb\ :sub:`2`
+      - Y'\ :sub:`2`
+      - Cr\ :sub:`2`
+      - Y'\ :sub:`3`
+    * .. _V4L2-PIX-FMT-VYUY:
+
+      - ``V4L2_PIX_FMT_VYUY``
+      - 'VYUY'
+
+      - Cr\ :sub:`0`
+      - Y'\ :sub:`0`
+      - Cb\ :sub:`0`
+      - Y'\ :sub:`1`
+      - Cr\ :sub:`2`
+      - Y'\ :sub:`2`
+      - Cb\ :sub:`2`
+      - Y'\ :sub:`3`
+    * .. _V4L2-PIX-FMT-YUYV:
+
+      - ``V4L2_PIX_FMT_YUYV``
+      - 'YUYV'
+
+      - Y'\ :sub:`0`
+      - Cb\ :sub:`0`
+      - Y'\ :sub:`1`
+      - Cr\ :sub:`0`
+      - Y'\ :sub:`2`
+      - Cb\ :sub:`2`
+      - Y'\ :sub:`3`
+      - Cr\ :sub:`2`
+    * .. _V4L2-PIX-FMT-YVYU:
+
+      - ``V4L2_PIX_FMT_YVYU``
+      - 'YVYU'
+
+      - Y'\ :sub:`0`
+      - Cr\ :sub:`0`
+      - Y'\ :sub:`1`
+      - Cb\ :sub:`0`
+      - Y'\ :sub:`2`
+      - Cr\ :sub:`2`
+      - Y'\ :sub:`3`
+      - Cb\ :sub:`2`
+
+**Color Sample Location:**
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.
+
+
+4:1:1 Subsampling
+=================
+
+This format subsamples the chroma components horizontally by 4, storing 8
+pixels in 12 bytes.
+
+.. flat-table:: Packed YUV 4:1:1 Formats
+    :header-rows: 1
+    :stub-columns: 0
+
+    * - Identifier
+      - Code
+      - Byte 0
+      - Byte 1
+      - Byte 2
+      - Byte 3
+      - Byte 4
+      - Byte 5
+      - Byte 6
+      - Byte 7
+      - Byte 8
+      - Byte 9
+      - Byte 10
+      - Byte 11
+    * .. _V4L2-PIX-FMT-Y41P:
+
+      - ``V4L2_PIX_FMT_Y41P``
+      - 'Y41P'
+
+      - Cb\ :sub:`0`
+      - Y'\ :sub:`0`
+      - Cr\ :sub:`0`
+      - Y'\ :sub:`1`
+      - Cb\ :sub:`4`
+      - Y'\ :sub:`2`
+      - Cr\ :sub:`4`
+      - Y'\ :sub:`3`
+      - Y'\ :sub:`4`
+      - Y'\ :sub:`5`
+      - Y'\ :sub:`6`
+      - Y'\ :sub:`7`
+
+.. note::
+
+    Do not confuse ``V4L2_PIX_FMT_Y41P`` with
+    :ref:`V4L2_PIX_FMT_YUV411P <V4L2-PIX-FMT-YUV411P>`. Y41P is derived from
+    "YUV 4:1:1 *packed*", while YUV411P stands for "YUV 4:1:1 *planar*".
+
+**Color Sample Location:**
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.