From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F2ABC433E0 for ; Mon, 25 Jan 2021 14:14:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1CB45230FD for ; Mon, 25 Jan 2021 14:14:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729342AbhAYOOF (ORCPT ); Mon, 25 Jan 2021 09:14:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729255AbhAYOIq (ORCPT ); Mon, 25 Jan 2021 09:08:46 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4BB6C0613D6; Mon, 25 Jan 2021 06:08:02 -0800 (PST) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 4BFC6331; Mon, 25 Jan 2021 15:08:00 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1611583680; bh=sjCWCuGQ91U+T/0nFlj+7MX712ur5d08TWXtqlvD9Xs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=capaosn0vDWFRiSnaj/PgDHhjjCNdRyMHGfJ1C5bC0PpylOK8672d0hQWb67KHpYr uFG8Pjl3xnehIVZafMYKWi3Hhs2OtCnwXLczhIHEvOAThLd8jxYltjHhrnLqt+kY10 L1mxh6zCIRRAoBb6/60Onp9daHe3kYpxEO26GdR8= Date: Mon, 25 Jan 2021 16:07:41 +0200 From: Laurent Pinchart To: Helen Koike Cc: linux-media@vger.kernel.org, hverkuil@xs4all.nl, hans.verkuil@cisco.com, kernel@collabora.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] media: doc: pixfmt-yuv: Fix 4:4:4 subsampling info Message-ID: References: <20210122182723.327438-1-helen.koike@collabora.com> <7f650d51-d419-53cc-0ad1-b241a10ab801@collabora.com> <9468d3e1-ac8b-8de7-5632-1da9119c992e@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <9468d3e1-ac8b-8de7-5632-1da9119c992e@collabora.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > >>> --- > >>> 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