From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.ffmpeg.org (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTPS id 1A64744B2E for ; Wed, 13 Aug 2025 14:25:50 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.ffmpeg.org (Postfix) with ESMTP id 8BB4468CCF4; Wed, 13 Aug 2025 17:25:46 +0300 (EEST) Received: from haasn.dev (haasn.dev [78.46.187.166]) by ffbox0-bg.ffmpeg.org (Postfix) with ESMTP id 6BD0D68BDE5 for ; Wed, 13 Aug 2025 17:25:39 +0300 (EEST) Received: from haasn.dev (unknown [10.30.1.1]) by haasn.dev (Postfix) with UTF8SMTP id 3B2B5403F0 for ; Wed, 13 Aug 2025 16:25:38 +0200 (CEST) Date: Wed, 13 Aug 2025 16:25:38 +0200 Message-ID: <20250813162538.GC676537@haasn.xyz> From: Niklas Haas To: FFmpeg development discussions and patches In-Reply-To: References: MIME-Version: 1.0 Content-Disposition: inline Subject: Re: [FFmpeg-devel] [PATCH] lavfi: protection against premultiplied alpha (was: The patch series about premultiplied alpha) 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: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On Mon, 11 Aug 2025 11:32:56 +0200 Nicolas George wrote: > Niklas Haas (HE12025-08-11): > > I still think this series overall is a step in the wrong direction; and that > > our goal should be to move towards negotiation, and not towards some IMO hacky > > flag that is already deprecated on arrival. > > In terms of work, this patch series is 5% trivial code easily removed > and 95% work that is necessary for real negotiation. > > Which means this patch series is a step in the right direction anyway. Updated https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20031 with full negotiation for the alpha mode. I also went ahead and fixed the drawutils filters to support premultiplied alpha, since it was low-hanging fruit. Now all the filters you were concerned about should be protected from receiving premultiplied alpha, at filter graph configuration time. > > > However, I decided I would rather just implement the full negotiation at this > > point, to save ourselves the continued discussion; especially in light of the > > TC's inaction / radio silence. > > > > Can you confirm that, if we implement full negotiation (thus allowing every > > filter to decide for itself which alpha modes it can ingest), your remaining > > your remaining objection to this series would be withdrawn? > > Of course. I suspect you widely underestimate the amount of work > necessary for real negotiation, but I would be happy to be proven wrong > on this issue. > > As I said multiple time, work on negotiation in libavfilter must start > with adding test coverage to avoid breaking the myriad of corner cases > that have been implemented over the years. I would be happy to review > your patches in this direction. Feel free to take over the old > preliminary ones I had posted a few years ago and never pushed. > > But whatever you choose, negotiation or hackish flag, I will stand firm > on the fact that the default must be to protect users from creating > invalid output. > > Regards, > > -- > Nicolas George > _______________________________________________ > 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". _______________________________________________ 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".