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Message-Id: <20220326183158.65303-1-sebastian.fricke@collabora.com>
Date: Sat, 26 Mar 2022 19:31:56 +0100
From: Sebastian Fricke <sebastian.fricke@...labora.com>
To: linux-media@...r.kernel.org
Cc: acourbot@...omium.org, tfiga@...omium.org,
hverkuil-cisco@...all.nl,
Sebastian Fricke <sebastian.fricke@...labora.com>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Maxime Ripard <mripard@...nel.org>,
Paul Kocialkowski <paul.kocialkowski@...tlin.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Chen-Yu Tsai <wens@...e.org>,
Jernej Skrabec <jernej.skrabec@...il.com>,
linux-kernel@...r.kernel.org (open list),
linux-staging@...ts.linux.dev (open list:STAGING SUBSYSTEM),
linux-arm-kernel@...ts.infradead.org (moderated list:ARM/Allwinner
sunXi SoC support),
linux-sunxi@...ts.linux.dev (open list:ARM/Allwinner sunXi SoC support)
Subject: [RFC PATCH 1/2] media: docs-rst: Append HEVC specific term
Describe the coding tree unit as replacement for the macroblock in the
HEVC codec. Highlight a key difference of the HEVC codec to predecessors
like AVC(H.264) to give a better overview of the differences between the
coding standards.
Signed-off-by: Sebastian Fricke <sebastian.fricke@...labora.com>
---
Documentation/userspace-api/media/v4l/dev-decoder.rst | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/Documentation/userspace-api/media/v4l/dev-decoder.rst b/Documentation/userspace-api/media/v4l/dev-decoder.rst
index 3cf2b496f2d0..eb5b1b1e3a51 100644
--- a/Documentation/userspace-api/media/v4l/dev-decoder.rst
+++ b/Documentation/userspace-api/media/v4l/dev-decoder.rst
@@ -72,6 +72,11 @@ coded resolution
coded width
width for given coded resolution.
+coding tree unit
+ processing unit of the HEVC codec (≘ macroblock units in H.264, VP8, VP9);
+ can use block structures of up to 64×64 pixels;
+ Good at sub-partitioning the picture into variable sized structures.
+
decode order
the order in which frames are decoded; may differ from display order if the
coded format includes a feature of frame reordering; for decoders,
@@ -104,7 +109,8 @@ keyframe
macroblock
a processing unit in image and video compression formats based on linear
block transforms (e.g. H.264, VP8, VP9); codec-specific, but for most of
- popular codecs the size is 16x16 samples (pixels).
+ popular codecs the size is 16x16 samples (pixels). The HEVC codec uses a
+ slightly more flexible processing unit called coding tree unit (CTU).
OUTPUT
the source buffer queue; for decoders, the queue of buffers containing
--
2.25.1
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