* [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info
@ 2021-01-22 18:27 Helen Koike
2021-01-23 9:56 ` Laurent Pinchart
0 siblings, 1 reply; 5+ messages in thread
From: Helen Koike @ 2021-01-22 18:27 UTC (permalink / raw)
To: linux-media
Cc: hverkuil, hans.verkuil, laurent.pinchart, kernel, linux-kernel
YUV 4:4:4 is not subsampled, fix this in the docs.
Fixes: da785536e007 ("media: doc: pixfmt-yuv: Move all semi-planar YUV formats to common file")
Signed-off-by: Helen Koike <helen.koike@collabora.com>
---
Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
index 7d4d39201a3f..bcb4ef24c334 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst
@@ -396,8 +396,8 @@ number of lines as the luma plane.
NV24 and NV42
-------------
-Semi-planar YUV 4:4:4 formats. The chroma plane is subsampled by 2 in the
-horizontal direction. Chroma lines contain half the number of pixels and the
+Semi-planar YUV 4:4:4 formats. No sub-sampling.
+Chroma lines contain the same number of pixels and the
same number of bytes as luma lines, and the chroma plane contains the same
number of lines as the luma plane.
--
2.30.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info 2021-01-22 18:27 [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info Helen Koike @ 2021-01-23 9:56 ` Laurent Pinchart 2021-01-25 13:57 ` Helen Koike 0 siblings, 1 reply; 5+ messages in thread From: Laurent Pinchart @ 2021-01-23 9:56 UTC (permalink / raw) To: Helen Koike; +Cc: linux-media, hverkuil, hans.verkuil, kernel, linux-kernel Hi Helen, Thank you for the patch. On Fri, Jan 22, 2021 at 03:27:23PM -0300, Helen Koike wrote: > YUV 4:4:4 is not subsampled, fix this in the docs. > > Fixes: da785536e007 ("media: doc: pixfmt-yuv: Move all semi-planar YUV formats to common file") > Signed-off-by: Helen Koike <helen.koike@collabora.com> > --- > Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst > index 7d4d39201a3f..bcb4ef24c334 100644 > --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst > +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst > @@ -396,8 +396,8 @@ number of lines as the luma plane. > NV24 and NV42 > ------------- > > -Semi-planar YUV 4:4:4 formats. The chroma plane is subsampled by 2 in the > -horizontal direction. Chroma lines contain half the number of pixels and the > +Semi-planar YUV 4:4:4 formats. No sub-sampling. "The chroma plane is not subsampled." ? > +Chroma lines contain the same number of pixels and the > same number of bytes as luma lines, and the chroma plane contains the same > number of lines as the luma plane. That's not quite right, the chroma lines contain twice the number of pixels and bytes, as there's one Cb and one Cr value in the chroma line for each Y value in the luma line. Maybe the text could be reflowed ? -- Regards, Laurent Pinchart ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info 2021-01-23 9:56 ` Laurent Pinchart @ 2021-01-25 13:57 ` Helen Koike 2021-01-25 14:02 ` Helen Koike 0 siblings, 1 reply; 5+ messages in thread From: Helen Koike @ 2021-01-25 13:57 UTC (permalink / raw) To: Laurent Pinchart Cc: linux-media, hverkuil, hans.verkuil, kernel, linux-kernel On 1/23/21 6:56 AM, Laurent Pinchart wrote: > Hi Helen, > > Thank you for the patch. > > On Fri, Jan 22, 2021 at 03:27:23PM -0300, Helen Koike wrote: >> YUV 4:4:4 is not subsampled, fix this in the docs. >> >> Fixes: da785536e007 ("media: doc: pixfmt-yuv: Move all semi-planar YUV formats to common file") >> Signed-off-by: Helen Koike <helen.koike@collabora.com> >> --- >> Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst >> index 7d4d39201a3f..bcb4ef24c334 100644 >> --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst >> +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst >> @@ -396,8 +396,8 @@ number of lines as the luma plane. >> NV24 and NV42 >> ------------- >> >> -Semi-planar YUV 4:4:4 formats. The chroma plane is subsampled by 2 in the >> -horizontal direction. Chroma lines contain half the number of pixels and the >> +Semi-planar YUV 4:4:4 formats. No sub-sampling. > > "The chroma plane is not subsampled." ? Ack. > >> +Chroma lines contain the same number of pixels and the >> same number of bytes as luma lines, and the chroma plane contains the same >> number of lines as the luma plane. > > That's not quite right, the chroma lines contain twice the number of > pixels and bytes, as there's one Cb and one Cr value in the chroma line > for each Y value in the luma line. > > > Maybe the text could be reflowed ? > Ack. I'll submit v2 updating the text. Thanks, Helen ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info 2021-01-25 13:57 ` Helen Koike @ 2021-01-25 14:02 ` Helen Koike 2021-01-25 14:07 ` Laurent Pinchart 0 siblings, 1 reply; 5+ messages in thread From: Helen Koike @ 2021-01-25 14:02 UTC (permalink / raw) To: Laurent Pinchart Cc: linux-media, hverkuil, hans.verkuil, kernel, linux-kernel On 1/25/21 10:57 AM, Helen Koike wrote: > > > On 1/23/21 6:56 AM, Laurent Pinchart wrote: >> Hi Helen, >> >> Thank you for the patch. >> >> On Fri, Jan 22, 2021 at 03:27:23PM -0300, Helen Koike wrote: >>> YUV 4:4:4 is not subsampled, fix this in the docs. >>> >>> Fixes: da785536e007 ("media: doc: pixfmt-yuv: Move all semi-planar YUV formats to common file") >>> Signed-off-by: Helen Koike <helen.koike@collabora.com> >>> --- >>> Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst >>> index 7d4d39201a3f..bcb4ef24c334 100644 >>> --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst >>> +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst >>> @@ -396,8 +396,8 @@ number of lines as the luma plane. >>> NV24 and NV42 >>> ------------- >>> >>> -Semi-planar YUV 4:4:4 formats. The chroma plane is subsampled by 2 in the >>> -horizontal direction. Chroma lines contain half the number of pixels and the >>> +Semi-planar YUV 4:4:4 formats. No sub-sampling. >> >> "The chroma plane is not subsampled." ? > > Ack. > >> >>> +Chroma lines contain the same number of pixels and the >>> same number of bytes as luma lines, and the chroma plane contains the same >>> number of lines as the luma plane. >> >> That's not quite right, the chroma lines contain twice the number of >> pixels and bytes, as there's one Cb and one Cr value in the chroma line >> for each Y value in the luma line. Actually, it is the same number o pixels, but twice the number o bytes. Since a trio (YCbCr) compose a pixel. At least this is how I understand comparing the logic of the text description of NV16 YUV4:2:2. Regards, Helen >> >> >> Maybe the text could be reflowed ? >> > > Ack. > > I'll submit v2 updating the text. > > Thanks, > Helen > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info 2021-01-25 14:02 ` Helen Koike @ 2021-01-25 14:07 ` Laurent Pinchart 0 siblings, 0 replies; 5+ messages in thread From: Laurent Pinchart @ 2021-01-25 14:07 UTC (permalink / raw) To: Helen Koike; +Cc: linux-media, hverkuil, hans.verkuil, kernel, linux-kernel Hi Helen, On Mon, Jan 25, 2021 at 11:02:01AM -0300, Helen Koike wrote: > On 1/25/21 10:57 AM, Helen Koike wrote: > > On 1/23/21 6:56 AM, Laurent Pinchart wrote: > >> On Fri, Jan 22, 2021 at 03:27:23PM -0300, Helen Koike wrote: > >>> YUV 4:4:4 is not subsampled, fix this in the docs. > >>> > >>> Fixes: da785536e007 ("media: doc: pixfmt-yuv: Move all semi-planar YUV formats to common file") > >>> Signed-off-by: Helen Koike <helen.koike@collabora.com> > >>> --- > >>> Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst | 4 ++-- > >>> 1 file changed, 2 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst > >>> index 7d4d39201a3f..bcb4ef24c334 100644 > >>> --- a/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst > >>> +++ b/Documentation/userspace-api/media/v4l/pixfmt-yuv-planar.rst > >>> @@ -396,8 +396,8 @@ number of lines as the luma plane. > >>> NV24 and NV42 > >>> ------------- > >>> > >>> -Semi-planar YUV 4:4:4 formats. The chroma plane is subsampled by 2 in the > >>> -horizontal direction. Chroma lines contain half the number of pixels and the > >>> +Semi-planar YUV 4:4:4 formats. No sub-sampling. > >> > >> "The chroma plane is not subsampled." ? > > > > Ack. > > > >>> +Chroma lines contain the same number of pixels and the > >>> same number of bytes as luma lines, and the chroma plane contains the same > >>> number of lines as the luma plane. > >> > >> That's not quite right, the chroma lines contain twice the number of > >> pixels and bytes, as there's one Cb and one Cr value in the chroma line > >> for each Y value in the luma line. > > Actually, it is the same number o pixels, but twice the number o bytes. > Since a trio (YCbCr) compose a pixel. > > At least this is how I understand comparing the logic of the text description > of NV16 YUV4:2:2. You're right, my bad. > >> Maybe the text could be reflowed ? > > > > Ack. > > > > I'll submit v2 updating the text. -- Regards, Laurent Pinchart ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-01-26 6:30 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-01-22 18:27 [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info Helen Koike 2021-01-23 9:56 ` Laurent Pinchart 2021-01-25 13:57 ` Helen Koike 2021-01-25 14:02 ` Helen Koike 2021-01-25 14:07 ` Laurent Pinchart
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