media: doc: pixfmt-yuv: Document subsampling in more details

Document YUV subsampling, including chroma spatial siting, and replace
the siting examples in individual formats by references to the common
documentation.

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>

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-m420.rst b/Documentation/userspace-api/media/v4l/pixfmt-m420.rst
index 13cf36a8cd5cb4242f7dd48a29e6820280f94dad..c01a949e7c11dee1fbd39aac11038392e83edd5e 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-m420.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-m420.rst
@@ -67,60 +67,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 1
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-    * - 2
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 3
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally and vertically.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-nv12.rst b/Documentation/userspace-api/media/v4l/pixfmt-nv12.rst
index dd2f38129fe66e1ec76a4f15547bc54a839329b7..692117bf83ada1ef5101575b3070840b7c3ab7cc 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-nv12.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-nv12.rst
@@ -72,58 +72,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 1
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-    * - 2
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 3
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally and vertically.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-nv12m.rst b/Documentation/userspace-api/media/v4l/pixfmt-nv12m.rst
index 250f8b97760504ad0f4c4caec897b79a2175e356..002b361d5a9b33707b48751c20bef4ad41cf4633 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-nv12m.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-nv12m.rst
@@ -84,61 +84,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 1
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-    * - 2
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      -
-      - C
-      -
-    * - 3
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally and vertically.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-nv16.rst b/Documentation/userspace-api/media/v4l/pixfmt-nv16.rst
index 22295fc0c35973f772df59dd5edd13d6568583fc..e6307843d84846243bec5b328d08cfe570c39d1c 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-nv16.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-nv16.rst
@@ -80,74 +80,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 1
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * -
-    * - 2
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 3
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-nv16m.rst b/Documentation/userspace-api/media/v4l/pixfmt-nv16m.rst
index 812bf2ccabf0ea778a44e29c6608ab488dc5fc59..58e97205d41fa75112508ba9d8fcaeec6dfa3df5 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-nv16m.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-nv16m.rst
@@ -84,74 +84,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 1
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * -
-    * - 2
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
-    * - 3
-      - Y
-      -
-      - Y
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      - C
-      -
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-uyvy.rst b/Documentation/userspace-api/media/v4l/pixfmt-uyvy.rst
index bae975fb14f66b837a99110702299e2c2c7e2432..1abc3066b7129b1b9a932b359392bba9d32769b5 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-uyvy.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-uyvy.rst
@@ -66,45 +66,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 1
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 2
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 3
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-vyuy.rst b/Documentation/userspace-api/media/v4l/pixfmt-vyuy.rst
index aff8588b67a948317e68020ddf05ffb2de6b5bdb..4fd0630a83a4f8a59c6221612227b323502995b3 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-vyuy.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-vyuy.rst
@@ -66,43 +66,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      -
-      - 2
-      - 3
-    * - 0
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 1
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 2
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 3
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-y41p.rst b/Documentation/userspace-api/media/v4l/pixfmt-y41p.rst
index d14cedf8f317518622b63e81ede0af2e18686a06..bb83eb6db3e5a627cf4d9ce3e8982fece5b418c1 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-y41p.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-y41p.rst
@@ -89,63 +89,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      - 1
-      -
-      - 2
-      - 3
-      - 4
-      - 5
-      -
-      - 6
-      - 7
-    * - 0
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-    * - 1
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-    * - 2
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-    * - 3
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv410.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv410.rst
index de2e519adc60f6868e3c844edcd3b07d4531165f..d79cd46d5055aad296ec60861d8d5dce31e0ad06 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv410.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv410.rst
@@ -68,60 +68,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      -
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-    * - 1
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-      -
-      -
-      -
-      - C
-      -
-      -
-      -
-    * - 2
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-    * - 3
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally and vertically.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv411p.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv411p.rst
index 998aa9b1328fce5f968a193cc954f0392938002f..8a70eeca8d839145d184208145eaafaad3fcb17a 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv411p.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv411p.rst
@@ -76,40 +76,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      - 1
-      -
-      - 2
-      - 3
-    * - 0
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-    * - 1
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-    * - 2
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
-    * - 3
-      - Y
-      - Y
-      - C
-      - Y
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv420.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv420.rst
index f1c7baf326852435b033fdbb8e7f15af5cb82156..a36ec8d6d8a46a77bdaac373791e3830968294e6 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv420.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv420.rst
@@ -77,67 +77,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      -
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      -
-      - C
-      -
-    * - 1
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-    * - 2
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      -
-      - C
-      -
-    * - 3
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally and vertically.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv420m.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv420m.rst
index cd20a57e06215fc6eb9850dabc8d94ea508dc2d6..c2cf17b9743c822dde685a0b529bcedbcc89512d 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv420m.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv420m.rst
@@ -86,67 +86,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      -
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      -
-      - C
-      -
-    * - 1
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-    * - 2
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
-    * -
-      -
-      - C
-      -
-      -
-      -
-      - C
-      -
-    * - 3
-      - Y
-      -
-      - Y
-      -
-      - Y
-      -
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally and vertically.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv422m.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv422m.rst
index 32bf15e1426e478084205da7ee2dcaf2b555f8b1..f92b54853fc97384a1ba5221a2bc2cf82b14a6bf 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv422m.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv422m.rst
@@ -97,45 +97,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 1
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 2
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 3
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv422p.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv422p.rst
index b178be558361d5232e47d03981be5365b6672241..33e6b923e3257152ff8b1b1473f7db151e2ce146 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv422p.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv422p.rst
@@ -85,45 +85,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 1
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 2
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 3
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv444m.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv444m.rst
index 90bdee2e2b0dd13897ce602662dd14f7c1d687c1..7c03cc5b07d95f8b83f93d9b8ee8f01e56ad9549 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv444m.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv444m.rst
@@ -107,35 +107,4 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      - 1
-      - 2
-      - 3
-    * - 0
-      - YC
-      - YC
-      - YC
-      - YC
-    * - 1
-      - YC
-      - YC
-      - YC
-      - YC
-    * - 2
-      - YC
-      - YC
-      - YC
-      - YC
-    * - 3
-      - YC
-      - YC
-      - YC
-      - YC
+Chroma samples are :ref:`co-sited<yuv-chroma-cosited>`.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuyv.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuyv.rst
index ca073a5098a96686276832e68455260e8659917d..4d5773922ba154e8b2f783a30814ed44a217a2f2 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuyv.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuyv.rst
@@ -69,50 +69,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      -
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      - C
-      - Y
-      -
-      - Y
-      - C
-      - Y
-    * - 1
-      - Y
-      - C
-      - Y
-      -
-      - Y
-      - C
-      - Y
-    * - 2
-      - Y
-      - C
-      - Y
-      -
-      - Y
-      - C
-      - Y
-    * - 3
-      - Y
-      - C
-      - Y
-      -
-      - Y
-      - C
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yvyu.rst b/Documentation/userspace-api/media/v4l/pixfmt-yvyu.rst
index 81ebec525ae5ca85daf15913f552ef145cba5c12..14b56b6113496ff13740e2f921abf4bfd49acb91 100644 (file)
--- a/Documentation/userspace-api/media/v4l/pixfmt-yvyu.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yvyu.rst
@@ -66,43 +66,5 @@ Each cell is one byte.
 
 
 **Color Sample Location:**
-
-.. flat-table::
-    :header-rows:  0
-    :stub-columns: 0
-
-    * -
-      - 0
-      -
-      - 1
-      - 2
-      -
-      - 3
-    * - 0
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 1
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 2
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
-    * - 3
-      - Y
-      - C
-      - Y
-      - Y
-      - C
-      - Y
+Chroma samples are :ref:`interstitially sited<yuv-chroma-centered>`
+horizontally.

diff --git a/Documentation/userspace-api/media/v4l/yuv-formats.rst b/Documentation/userspace-api/media/v4l/yuv-formats.rst
index 4a05a105a9e6cb10732f40431c106c9bd7c4a065..79a4fda566c6c63d1a6d3d2d4876149c9e756160 100644 (file)
--- a/Documentation/userspace-api/media/v4l/yuv-formats.rst
+++ b/Documentation/userspace-api/media/v4l/yuv-formats.rst
@@ -14,11 +14,251 @@ reconstructed by subtracting from the brightness component. See
 :ref:`colorspaces` for conversion examples. YUV was chosen because
 early television would only transmit brightness information. To add
 color in a way compatible with existing receivers a new signal carrier
-was added to transmit the color difference signals. Secondary in the YUV
-format the U and V components usually have lower resolution than the Y
-component. This is an analog video compression technique taking
-advantage of a property of the human visual system, being more sensitive
-to brightness information.
+was added to transmit the color difference signals.
+
+
+Subsampling
+===========
+
+YUV formats commonly encode images with a lower resolution for the chroma
+components than for the luma component. This compression technique, taking
+advantage of the human eye being more sensitive to luminance than color
+differences, is called chroma subsampling.
+
+While many combinations of subsampling factors in the horizontal and vertical
+direction are possible, common factors are 1 (no subsampling), 2 and 4, with
+horizontal subsampling always larger than or equal to vertical subsampling.
+Common combinations are named as follows.
+
+- `4:4:4`: No subsampling
+- `4:2:2`: Horizontal subsampling by 2, no vertical subsampling
+- `4:2:0`: Horizontal subsampling by 2, vertical subsampling by 2
+- `4:1:1`: Horizontal subsampling by 4, no vertical subsampling
+- `4:1:0`: Horizontal subsampling by 4, vertical subsampling by 4
+
+Subsampling the chroma component effectively creates chroma values that can be
+located in different spatial locations:
+
+- .. _yuv-chroma-centered:
+
+  The subsampled chroma value may be calculated by simply averaging the chroma
+  value of two consecutive pixels. It effectively models the chroma of a pixel
+  sited between the two original pixels. This is referred to as centered or
+  interstitially sited chroma.
+
+- .. _yuv-chroma-cosited:
+
+  The other option is to subsample chroma values in a way that place them in
+  the same spatial sites as the pixels. This may be performed by skipping every
+  other chroma sample (creating aliasing artifacts), or with filters using an
+  odd number of taps. This is referred to as co-sited chroma.
+
+The following examples show different combination of chroma siting in a 4x4
+image.
+
+.. flat-table:: 4:2:2 subsampling, interstitially sited
+    :header-rows: 1
+    :stub-columns: 1
+
+    * -
+      - 0
+      -
+      - 1
+      -
+      - 2
+      -
+      - 3
+    * - 0
+      - Y
+      - C
+      - Y
+      -
+      - Y
+      - C
+      - Y
+    * - 1
+      - Y
+      - C
+      - Y
+      -
+      - Y
+      - C
+      - Y
+    * - 2
+      - Y
+      - C
+      - Y
+      -
+      - Y
+      - C
+      - Y
+    * - 3
+      - Y
+      - C
+      - Y
+      -
+      - Y
+      - C
+      - Y
+
+.. flat-table:: 4:2:2 subsampling, co-sited
+    :header-rows: 1
+    :stub-columns: 1
+
+    * -
+      - 0
+      -
+      - 1
+      -
+      - 2
+      -
+      - 3
+    * - 0
+      - Y/C
+      -
+      - Y
+      -
+      - Y/C
+      -
+      - Y
+    * - 1
+      - Y/C
+      -
+      - Y
+      -
+      - Y/C
+      -
+      - Y
+    * - 2
+      - Y/C
+      -
+      - Y
+      -
+      - Y/C
+      -
+      - Y
+    * - 3
+      - Y/C
+      -
+      - Y
+      -
+      - Y/C
+      -
+      - Y
+
+.. flat-table:: 4:2:0 subsampling, horizontally interstitially sited, vertically co-sited
+    :header-rows: 1
+    :stub-columns: 1
+
+    * -
+      - 0
+      -
+      - 1
+      -
+      - 2
+      -
+      - 3
+    * - 0
+      - Y
+      - C
+      - Y
+      -
+      - Y
+      - C
+      - Y
+    * - 1
+      - Y
+      -
+      - Y
+      -
+      - Y
+      -
+      - Y
+    * - 2
+      - Y
+      - C
+      - Y
+      -
+      - Y
+      - C
+      - Y
+    * - 3
+      - Y
+      -
+      - Y
+      -
+      - Y
+      -
+      - Y
+
+.. flat-table:: 4:1:0 subsampling, horizontally and vertically interstitially sited
+    :header-rows: 1
+    :stub-columns: 1
+
+    * -
+      - 0
+      -
+      - 1
+      -
+      - 2
+      -
+      - 3
+    * - 0
+      - Y
+      -
+      - Y
+      -
+      - Y
+      -
+      - Y
+    * -
+      -
+      -
+      -
+      -
+      -
+      -
+      -
+    * - 1
+      - Y
+      -
+      - Y
+      -
+      - Y
+      -
+      - Y
+    * -
+      -
+      -
+      -
+      - C
+      -
+      -
+      -
+    * - 2
+      - Y
+      -
+      - Y
+      -
+      - Y
+      -
+      - Y
+    * -
+      -
+      -
+      -
+      -
+      -
+      -
+      -
+    * - 3
+      - Y
+      -
+      - Y
+      -
+      - Y
+      -
+      - Y
 
 
 .. toctree::