Re: [PATCH 5/5] docs: uapi: media: Document Mediatek 10bit tiled formats

From: Andrzej Pietrasiewicz
Date: Mon Aug 07 2023 - 14:35:44 EST

Hi Nicolas,

W dniu 4.08.2023 o 21:27, Nicolas Dufresne pisze:
Document V4L2_PIX_FMT_MT2110T and V4L2_PIX_FMT_MT2110R. These two
formats are nearly identical, reusing MM21 format and expending it
by inserting chunk of 16 bytes of lower 2 bit pixel data after each
chunk of 64 bytes higher 8 bit of data.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
---
.../media/v4l/pixfmt-reserved.rst | 13 --
.../media/v4l/pixfmt-yuv-planar.rst | 122 ++++++++++++++++++
2 files changed, 122 insertions(+), 13 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
index 296ad2025e8d..58f6ae25b2e7 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
@@ -275,19 +275,6 @@ please make a proposal on the linux-media mailing list.
Decoder's implementation can be found here,
`aspeed_codec <https://github.com/AspeedTech-BMC/aspeed_codec/>`__
- * .. _V4L2-PIX-FMT-MT2110T:
-
- - ``V4L2_PIX_FMT_MT2110T``
- - 'MT2110T'
- - This format is two-planar 10-Bit tile mode and having similitude with
- ``V4L2_PIX_FMT_MM21`` in term of alignment and tiling. Used for VP9, AV1
- and HEVC.
- * .. _V4L2-PIX-FMT-MT2110R:
-
- - ``V4L2_PIX_FMT_MT2110R``
- - 'MT2110R'
- - This format is two-planar 10-Bit raster mode and having similitude with
- ``V4L2_PIX_FMT_MM21`` in term of alignment and tiling. Used for AVC.
.. raw:: latex
\normalsize
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
index 052927bd9396..6ef5cd6bd9e2 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
@@ -144,6 +144,20 @@ All components are stored with the same number of bits per component.
- Cb, Cr
- Yes
- 4x4 tiles
+ * - V4L2_PIX_FMT_MT2110T
+ - 'MT2T'
+ - 15
+ - 4:2:0
+ - Cb, Cr
+ - No
+ - 16x32 / 16x16 tiles tiled low bits
+ * - V4L2_PIX_FMT_MT2110R
+ - 'MT2R'
+ - 15
+ - 4:2:0
+ - Cb, Cr
+ - No
+ - 16x32 / 16x16 tiles raster low bits
* - V4L2_PIX_FMT_NV16
- 'NV16'
- 8
@@ -369,6 +383,8 @@ two non-contiguous planes.
.. _V4L2-PIX-FMT-NV15-4L4:
.. _V4L2-PIX-FMT-NV12M-10BE-8L128:
.. _V4L2-PIX-FMT-NV12-10BE-8L128:
+.. _V4L2-PIX-FMT-MT2110T:
+.. _V4L2-PIX-FMT-MT2110R:
Tiled NV15
----------
@@ -453,6 +469,112 @@ it means that the low bits and high bits of one pixel may be in different tiles.
``V4L2_PIX_FMT_NV12_10BE_8L128`` is similar to ``V4L2_PIX_FMT_NV12M_10BE_8L128`` but stores
two planes in one memory.
+``V4L2_PIX_FMT_MT2110T``` is one of Mediatek packed 10bit YUV 4:2:0 formats.
+It is fully packed 10bit 4:2:0 format like NV15 (15 bits per pixel), except
+that the lower two bits data is stored in separate partitions. The format is
+composed of 16x32 luma tiles, and 16x16 chroma tiles. Each tiles have 640

Each tile is 640 bytes long, divided into 8 partitions of 80 bytes?

+bytes separate in 8 partitions of 80 bytes each. The first 64 bytes represents

bytes represent? (plural)

+the 8 most significant bits of pixel data. The remaining 16 bytes contains the

contain? (plural)

+2 least significant of pixel data.

least significant bits?

Regards,

Andrzej


+
+.. kernel-figure:: mt2110t.svg
+ :alt: mt2110t.svg
+ :align: center
+
+ Layout of Example MT2110T Chroma Tile
+
+Filtering out the lower part of each partitions results in a valid
+``V4L2_PIX_FMT_MM21`` frame. A partition is a sub-tile of size 16 x 4. The
+lower two bits is said to be tiled since each bytes contains the lower two
+bits of the column of for pixel matching the same index. The chroma tiles
+only have 4 partitions.
+
+.. flat-table:: MT2110T LSB bits layout
+ :header-rows: 1
+ :stub-columns: 0
+
+ * -
+ - start + 0
+ - start + 1
+ - . . .
+ - start\ +\ 15
+ * - bits 0:2
+ - Y'\ :sub:`0:0`
+ - Y'\ :sub:`0:1`
+ - . . .
+ - Y'\ :sub:`0:15`
+ * - bits 2:3
+ - Y'\ :sub:`1:0`
+ - Y'\ :sub:`1:1`
+ - . . .
+ - Y'\ :sub:`1:15`
+ * - bits 4:5
+ - Y'\ :sub:`2:0`
+ - Y'\ :sub:`2:1`
+ - . . .
+ - Y'\ :sub:`2:15`
+ * - bits 6:7
+ - Y'\ :sub:`3:0`
+ - Y'\ :sub:`3:1`
+ - . . .
+ - Y'\ :sub:`3:15`
+
+``V4L2_PIX_FMT_MT2110R`` is identical to ``V4L2_PIX_FMT_MT2110T`` except that
+the least significant two bits layout is in raster order. This means the first byte
+contains 4 pixels of the first row, with 4 bytes per line.
+
+.. flat-table:: MT2110R LSB bits layout
+ :header-rows: 1
+ :stub-columns: 0
+
+ * -
+ - b0
+ -
+ -
+ -
+ - ...
+ - b3
+ * - start + 0
+ - Y'\ :sub:`0:0`
+ - Y'\ :sub:`0:1`
+ - Y'\ :sub:`0:2`
+ - Y'\ :sub:`0:3`
+ - ...
+ - Y'\ :sub:`0:12`
+ - Y'\ :sub:`0:13`
+ - Y'\ :sub:`0:14`
+ - Y'\ :sub:`0:15`
+ * - start + 4
+ - Y'\ :sub:`1:0`
+ - Y'\ :sub:`1:1`
+ - Y'\ :sub:`1:2`
+ - Y'\ :sub:`1:3`
+ - ...
+ - Y'\ :sub:`1:12`
+ - Y'\ :sub:`1:13`
+ - Y'\ :sub:`1:14`
+ - Y'\ :sub:`1:15`
+ * - start + 8
+ - Y'\ :sub:`2:0`
+ - Y'\ :sub:`2:1`
+ - Y'\ :sub:`2:2`
+ - Y'\ :sub:`2:3`
+ - ...
+ - Y'\ :sub:`2:12`
+ - Y'\ :sub:`2:13`
+ - Y'\ :sub:`2:14`
+ - Y'\ :sub:`2:15`
+ * - start\ +\ 12
+ - Y'\ :sub:`3:0`
+ - Y'\ :sub:`3:1`
+ - Y'\ :sub:`3:2`
+ - Y'\ :sub:`3:3`
+ - ...
+ - Y'\ :sub:`3:12`
+ - Y'\ :sub:`3:13`
+ - Y'\ :sub:`3:14`
+ - Y'\ :sub:`3:15`
+
.. _V4L2-PIX-FMT-NV16:
.. _V4L2-PIX-FMT-NV61: