From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 27DDF42912 for ; Sat, 6 Aug 2022 10:36:07 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 6546368B70B; Sat, 6 Aug 2022 13:36:06 +0300 (EEST) Received: from nef.ens.fr (nef2.ens.fr [129.199.96.40]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 79CB968B0F2 for ; Sat, 6 Aug 2022 13:36:04 +0300 (EEST) X-ENS-nef-client: 129.199.129.80 ( name = phare.normalesup.org ) Received: from phare.normalesup.org (phare.normalesup.org [129.199.129.80]) by nef.ens.fr (8.14.4/1.01.28121999) with ESMTP id 276Aa3v5021074 for ; Sat, 6 Aug 2022 12:36:04 +0200 Received: by phare.normalesup.org (Postfix, from userid 1001) id E9BC2EB5BC; Sat, 6 Aug 2022 12:36:03 +0200 (CEST) Date: Sat, 6 Aug 2022 12:36:03 +0200 From: Nicolas George To: FFmpeg development discussions and patches Message-ID: References: <20220802165421.137563-1-george@nsup.org> <20220804134924.GJ2088045@pb2> <20220804150441.GL2088045@pb2> MIME-Version: 1.0 In-Reply-To: <20220804150441.GL2088045@pb2> Subject: Re: [FFmpeg-devel] [PATCH 1/7] lavu/pixfmt: summarize yuv naming conventions X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: multipart/mixed; boundary="===============2280765319115214471==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============2280765319115214471== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="4AiNyAkWJzddPzq5" Content-Disposition: inline --4AiNyAkWJzddPzq5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Michael Niedermayer (12022-08-04): > I suspect several filters are somewhat "wrong" > for example hflip fliping 4:1:1 > would turn a: *--- into ---* > where * is teh chroma sample location, i dont think it updates the chroma > sample location metadata nor does it apply some filter to chroma to shift= by > 3/4 samples. so it looks wrong, one of the 2 is neeed. >=20 > vf_scale contains some code to handle this but iam not seeing code consid= ering > the input and output frames chroma location metadata >=20 > All this leads to small errors, often probably not vissible > when you have one one chroma sample for 4 luma samples you will always ha= ve > some artifacts on sharp color edges, if the location of the chroma sample > is wrong the artifact would be more to one side of a diagonal edge than t= he > other. If the locations are correct it should be more symmetric in theory. I think I understand. Would it be ok to apply this with the added comment: * Note: this is a quick mnemonic representation of the pixels; actual * interaction between chroma and luma is more complex, see * AVChromaLocation in pixfmt.h. ? Regards, --=20 Nicolas George --4AiNyAkWJzddPzq5 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE6ooRQGBoNzw0KnwPcZVLI8pNxgwFAmLuRBEACgkQcZVLI8pN xgwTPw//cMOc3/wkQkDl/FdEhz6xdJ3iVmqoyqpuDeN6iaehEHLe2F/MkXH+MSFT 3Zg2iseBHPKNQaMq5cwB9bGaPjFe6XY4Y7/Kly1HmB7e/Wdvw28BJC4XFchC6kTa t1RZAONx/RJKAM+HhQgCTquwf+w53T1oVcpyKZ2LLQ1s2X3khrVvZhJIv/GjdLwO TAmH/7mEOkr8C0Jn9L21WmDlZMCskjZCiUuFLnf6+38nVF0dnj3Dv/WAZexLaHg+ 7u2euOx0b1489Dcz9EfFZrEACQF9L3C/OtoBDu8IrZafqwmrpBh9+pmCGzd5Z1/q NQDtRE+a++5QlOk3bJEXOwtKpNE9JFiz6MC/NcCYAOOFW5CaN+6hL0X4w50NCRVo R+unC/zPcx1qMSRB3xGycJYgHRp4faUJaAXMRZQMRzEHxd6R80dBG9OLCu1dQXoI GJ8/xj9HJMcTCCQ9SN5x5VdSP64IKRUFKJqeCN/gnCwi9Lk+7M4qi8n56ThFouB4 A5kgZuJa5pMIRe7sml8DVuWciLbZYGse6aVxEEjfUEmDgMs/kkTXmfL/kx0WEzMP 45gHDF2as2C5BkfvmNjqfDmvMiSsBaIuLvxl+LNcWccZWGsnFKAbhgG3SlQTVrjA 8v0qhLO7+Z78/p2zcGhvPJI3KLp6d1YjRR4MBdbnHztYSLPy8ok= =CybU -----END PGP SIGNATURE----- --4AiNyAkWJzddPzq5-- --===============2280765319115214471== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". --===============2280765319115214471==--