Re: [PATCH 2/7] docs: uapi: media: Document Raspberry Pi NV12 column format
From: Sakari Ailus <sakari.ailus@linux.intel.com>
Date: 2025-01-08 08:09:16
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linux-arm-kernel, linux-media, lkml
Hi Dave, Thanks for the set. On Fri, Dec 20, 2024 at 04:21:13PM +0000, Dave Stevenson wrote:
quoted hunk ↗ jump to hunk
The Raspberry Pi HEVC decoder uses a tiled format based on columns for 8 and 10 bit YUV images, so document them as NV12MT_COL128 and NV12MT_10_COL128. Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com> --- .../userspace-api/media/v4l/pixfmt-yuv-planar.rst | 42 ++++++++++++++++++++++ 1 file changed, 42 insertions(+)diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst index b788f6933855..90414491d7b5 100644 --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst@@ -827,6 +827,48 @@ Data in the 12 high bits, zeros in the 4 low bits, arranged in little endian ord - Cb\ :sub:`11` - Cr\ :sub:`11` +NV12MT_COL128 and NV12MT_10_COL128
Please use full macro names of the formats here.
+---------------------------------- + +``V4L2_PIX_FMT_NV12MT_COL128`` is a tiled version of +``V4L2_PIX_FMT_NV12M`` where the two planes are split into 128 byte wide columns +of Y or interleaved CbCr. + +NV12MT_10_COL128 expands that as a 10 bit format where 3 10 bit values are
Ditto.
+packed into a 32bit word. A 128 byte wide column therefore holds 96 samples
+(either Y or interleaved CrCb). That effectively makes it 6 values in a 64 bit
+word for the CbCr plane, as the values always go in pairs.
+
+Bit-packed representation.
+
+.. tabularcolumns:: |p{1.2cm}||p{1.2cm}||p{1.2cm}||p{1.2cm}|p{3.2cm}|p{3.2cm}|
+
+.. flat-table::
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 8 8 8 8
+
+ * - Y'\ :sub:`00[7:0]`
+ - Y'\ :sub:`01[5:0] (bits 7--2)` Y'\ :sub:`00[9:8]`\ (bits 1--0)
+ - Y'\ :sub:`02[3:0] (bits 7--4)` Y'\ :sub:`01[9:6]`\ (bits 3--0)
+ - unused (bits 7--6)` Y'\ :sub:`02[9:4]`\ (bits 5--0)
+
+.. tabularcolumns:: |p{1.2cm}||p{1.2cm}||p{1.2cm}||p{1.2cm}|p{3.2cm}|p{3.2cm}|
+
+.. flat-table::
+ :header-rows: 0
+ :stub-columns: 0
+ :widths: 12 12 12 12 12 12 12 12
+
+ * - Cb\ :sub:`00[7:0]`
+ - Cr\ :sub:`00[5:0]`\ (bits 7--2) Cb\ :sub:`00[9:8]`\ (bits 1--0)
+ - Cb\ :sub:`01[3:0]`\ (bits 7--4) Cr\ :sub:`00[9:6]`\ (bits 3--0)
+ - unused (bits 7--6) Cb\ :sub:`02[9:4]`\ (bits 5--0)
+ - Cr\ :sub:`01[7:0]`
+ - Cb\ :sub:`02[5:0]`\ (bits 7--2) Cr\ :sub:`01[9:8]`\ (bits 1--0)
+ - Cr\ :sub:`02[3:0]`\ (bits 7--4) Cb\ :sub:`02[9:6]`\ (bits 3--0)
+ - unused (bits 7--6) Cr\ :sub:`02[9:4]`\ (bits 5--0)
+
Fully Planar YUV Formats
========================-- Kind regards, Sakari Ailus