On Tue, 27 Jul 2021 at 14:58, Nicolas Dufresne [off-list ref] wrote:

Le mardi 27 juillet 2021 à 11:20 +0800, Ming Qian a écrit :

quoted

NT8 is 8-bit tiled nv12 format used by amphion decoder.
NT10 is 10-bit tiled format used by amphion decoder.
The tile size is 8x128

Signed-off-by: Ming Qian <ming.qian@nxp.com>
Signed-off-by: Shijie Qin <redacted>
Signed-off-by: Zhou Peng <eagle.zhou@nxp.com>
---
 .../userspace-api/media/v4l/pixfmt-reserved.rst   | 15 +++++++++++++++
 drivers/media/v4l2-core/v4l2-ioctl.c              |  2 ++
 include/uapi/linux/videodev2.h                    |  2 ++
 3 files changed, 19 insertions(+)

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
index c9231e18859b..2deae49210a7 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst

@@ -256,3 +256,18 @@ please make a proposal on the linux-media mailing list.
      of tiles, resulting in 32-aligned resolutions for the luminance plane
      and 16-aligned resolutions for the chrominance plane (with 2x2
      subsampling).
+    * .. _V4L2-PIX-FMT-NT8:
+
+      - ``V4L2_PIX_FMT_NT8``
+      - 'NA12'
+      - Two-planar NV12-based format used by the video engine found on Amphion decoder,
+    with 8x128 tiles for the luminance plane and chrominance plane.
+    The number of bytes in one luminance or chrominance row must be divisible by 256.
+    * .. _V4L2-PIX-FMT-NT10:

There is a large spread of "vendor specific" format that aren't really specific,
or complex enough to be worth being marked as vendor format. As per my reading
of this description, this is linearly layout 8x128 tiled format, with no
compression or anything (well unless you forgot to mention). As a side effect,
we should give that format an explicit name (NT8 is cryptic). What about
V4L2_PIX_FMT_NV12_8L128, my colleague is about to send a proposal in that
direction. That would be NV12 with plane tiled 8x128 bytes and layout linearly,
row by row, left to right. We already have cryptic formats like SUNXI, HM12 that
are literally just that, simple tiling, and we endup having to use obscure
vendor name whenever other HW uses the same.

(this comment extends to the other formats here)

Here's the proposal Nicolas is talking about:

https://lore.kernel.org/linux-media/20210727145745.25203-1-ezequiel@collabora.com/T/#t (local)

V4L2_PIX_FMT_NV12_8L128 makes sense, please also add support for this
format in GStreamer. I think that makes it easier to confirm the
layout of the format.

Thanks!
Ezequiel

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