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authorSebastian Fricke <sebastian.fricke@collabora.com>2022-03-29 08:56:56 +0200
committerMauro Carvalho Chehab <mchehab@kernel.org>2022-05-13 11:02:19 +0200
commit87581a9ef5616b903a3d0edab0eae77c266d1e38 (patch)
tree61c5659abaa46826b09e9282d8c067484db4f696 /Documentation
parent6a5446f97b1c3add10d371590e7b09157f3c96fc (diff)
downloadlinux-87581a9ef5616b903a3d0edab0eae77c266d1e38.tar.gz
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.

[hverkuil: replaced the 'corresponds to' symbol with the full text for clarity]

Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/userspace-api/media/v4l/dev-decoder.rst9
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/userspace-api/media/v4l/dev-decoder.rst b/Documentation/userspace-api/media/v4l/dev-decoder.rst
index 3cf2b496f2d0..675bc2c3c6b8 100644
--- a/Documentation/userspace-api/media/v4l/dev-decoder.rst
+++ b/Documentation/userspace-api/media/v4l/dev-decoder.rst
@@ -72,6 +72,12 @@ coded resolution
 coded width
    width for given coded resolution.
 
+coding tree unit
+   processing unit of the HEVC codec (corresponds to 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 +110,8 @@ 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