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 43FC3423BF for ; Sun, 15 May 2022 18:55:59 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 9751668B02F; Sun, 15 May 2022 21:55:57 +0300 (EEST) Received: from relay11.mail.gandi.net (relay11.mail.gandi.net [217.70.178.231]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 5FA0468B02F for ; Sun, 15 May 2022 21:55:51 +0300 (EEST) Received: from localhost (213-47-68-29.cable.dynamic.surfer.at [213.47.68.29]) (Authenticated sender: michael@niedermayer.cc) by mail.gandi.net (Postfix) with ESMTPSA id 76FCD100002 for ; Sun, 15 May 2022 18:55:50 +0000 (UTC) Date: Sun, 15 May 2022 20:55:49 +0200 From: Michael Niedermayer To: FFmpeg development discussions and patches Message-ID: <20220515185549.GO396728@pb2> References: <20220513154208.17941-1-leo.izen@gmail.com> <20220513212245.GN396728@pb2> MIME-Version: 1.0 In-Reply-To: Subject: Re: [FFmpeg-devel] [PATCH] avutil/csp: create public API for colorspace structs 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="===============7522448358625268469==" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: --===============7522448358625268469== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="68uOmRXIw+u8y5pO" Content-Disposition: inline --68uOmRXIw+u8y5pO Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, May 15, 2022 at 12:49:51PM -0400, Ronald S. Bultje wrote: > Hi, >=20 > On Fri, May 13, 2022 at 5:22 PM Michael Niedermayer > wrote: >=20 > > On Fri, May 13, 2022 at 11:42:08AM -0400, Leo Izen wrote: > > > This commit moves some of the functionality from avfilter/colorspace > > > into avutil/csp and exposes it as a public API so it can be used by > > > libavcodec and/or libavformat. > > [...] > > > diff --git a/libavutil/csp.h b/libavutil/csp.h > > > new file mode 100644 > > > index 0000000000..1bcde7ddd3 > > > --- /dev/null > > > +++ b/libavutil/csp.h > > > @@ -0,0 +1,49 @@ > > > +/* > > > + * Copyright (c) 2016 Ronald S. Bultje > > > + * This file is part of FFmpeg. > > > + * > > > + * FFmpeg is free software; you can redistribute it and/or > > > + * modify it under the terms of the GNU Lesser General Public > > > + * License as published by the Free Software Foundation; either > > > + * version 2.1 of the License, or (at your option) any later version. > > > + * > > > + * FFmpeg is distributed in the hope that it will be useful, > > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > > > + * Lesser General Public License for more details. > > > + * > > > + * You should have received a copy of the GNU Lesser General Public > > > + * License along with FFmpeg; if not, write to the Free Software > > > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA > > 02110-1301 USA > > > + */ > > > + > > > +#ifndef AVUTIL_CSP_H > > > +#define AVUTIL_CSP_H > > > + > > > +#include "libavutil/frame.h" > > > +#include "libavutil/pixfmt.h" > > > + > > > +struct LumaCoefficients { > > > + double cr, cg, cb; > > > +}; > > > + > > > +struct PrimaryCoefficients { > > > + double xr, yr, xg, yg, xb, yb; > > > +}; > > > + > > > +struct WhitepointCoefficients { > > > + double xw, yw; > > > +}; > > > > I think we should avoid floating point so as to ensure reproduceable > > results and simplify regerssion testing > > >=20 > To explain: when I designed this stuff, I chose to keep them in float so > that we can use the literal values from the specs, which are themselves in > floating point. That would not be possible anymore, and would therefore > make it slightly harder to read for a casual observer. >=20 > (Otherwise no opinion, I'm typically used to fixed-point rather than > floating-point myself also.) I looked at Rec. ITU-T H.264 (02/2016) (was the first thing laying around, i assume but did not check that this matches the specs these numbers came f= rom) (randomly picking "whitepoints") the whitepoints for "10" contain some 1/3 values but if i just look at "1" the values are 0.3127, 0.3290 i dont think these can be represented as m*2^E either 3127/10000 =3D m*2^E 3127 * 2^-E =3D m * 10000 both sides would be all integers the right side contains 5 as factor, the left doesnt of course i may be missing something thx [...] --=20 Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB During times of universal deceit, telling the truth becomes a revolutionary act. -- George Orwell --68uOmRXIw+u8y5pO Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABEIAB0WIQSf8hKLFH72cwut8TNhHseHBAsPqwUCYoFMsQAKCRBhHseHBAsP q1YzAJ9iQojdhjxU3Arz4oFxHjsk7W8UNQCfbBkx2PKt+yGB1Sj4x41mn/193NQ= =Yi5j -----END PGP SIGNATURE----- --68uOmRXIw+u8y5pO-- --===============7522448358625268469== 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". --===============7522448358625268469==--