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 E2E384A945 for ; Wed, 24 Apr 2024 11:40:37 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id E040568D2AF; Wed, 24 Apr 2024 14:40:33 +0300 (EEST) Received: from haasn.dev (haasn.dev [78.46.187.166]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 4AFF468CD27 for ; Wed, 24 Apr 2024 14:40:27 +0300 (EEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=haasn.xyz; s=mail; t=1713958827; bh=bhduOQTNb0Pp423TlgH/tcz6k9rJYg8lcF3GU0qMGD8=; h=Date:From:To:Subject:In-Reply-To:References:From; b=XW4jI/p9xwQb1rIe/7OEgUqkR5ZkA7iIN0cUymchhgLYmjQlAbVHxi3i68JvAJm3D bDAhxgwTA4D7DJ5YSzqn6YeNMXz1d7UNtoxCQ6wznKSzFNkOY4c13eiM+u/IXNPY+I xB+VXvxAexCa1xeo36gkX3nIUOZVpoQx+JIpEzlQ= Received: from haasn.dev (unknown [10.30.0.2]) by haasn.dev (Postfix) with ESMTP id 0088C40356 for ; Wed, 24 Apr 2024 13:40:26 +0200 (CEST) Date: Wed, 24 Apr 2024 13:40:26 +0200 Message-ID: <20240424134026.GB46942@haasn.xyz> From: Niklas Haas To: ffmpeg-devel@ffmpeg.org In-Reply-To: References: <20240424110257.38715-1-ffmpeg@haasn.xyz> MIME-Version: 1.0 Content-Disposition: inline Subject: Re: [FFmpeg-devel] [PATCH 0/5] replace scale2ref by scale=rw:rh 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 Wed, 24 Apr 2024 16:48:54 +0530 Gyan Doshi wrote: > > > On 2024-04-24 04:21 pm, Niklas Haas wrote: > > As discussed in my previous series for fixing scale2ref[1], this filter > > is fundamentally broken, and the only real fix would be to switch to > > activate(), or ideally FFFrameSync. > > > > [1] https://ffmpeg.org//pipermail/ffmpeg-devel/2024-March/323382.html > > > > The main thing making this difficult is the fact that scale2ref also > > wants to output ref frames to its secondary output, which FFFrameSync > > does not support, and which is ultimately at least part of the root > > cause of trac #10795. > > > > Since this is in principle completely unnecessary (users can just > > 'split' the ref input and have it be consumed by vf_scale), and to make > > the design of this filter a bit more robust and maintainable, switch to > > an approach where vf_scale itself gains the ability to reference > > a secondary input stream, using the "ref_*" series of variables. > > > > This makes the current [i][ri]scale2ref[o][ro] equivalent to the only > > slightly more verbose [ri]split[t][ro]; [i][t]scale=rw:rh[o]. (And > > conversely, it is no longer necessary to use nullsink to consume an > > unused [ro]) > > In principle, a good idea, but how does this impact memory use and speed > in the not-so-uncommon scenario where multiple overlay targets are > scaled 2 ref and then overlaid > e.g. > > in current flow: > > [a][base]scale2ref[a][ref]; > [b][ref]scale2ref[b][ref[; > [c][ref]scale2ref[c][ref[; > [d][ref]scale2ref[d][ref[; > [ref][a]overlay[ref]; > [ref][b]overlay[ref]; > [ref][c]overlay[ref]; > [ref][d]overlay[ref]; > > in new flow: > > [base]split=5[base][refa][refb][refc][refd]; > [a][refa]scale[a]; > [b][refb]scale[b]; > [c][refc]scale[c]; > [d][refd]scale[d]; > [base][a]overlay[outa]; > [outa][b]overlay[outb]; > [outb][c]overlay[outc]; > [outc][d]overlay[out]; > > > Regards, > Gyan I have not tested it exactly, but based on my understanding of libavfilter it shouldn't affect memory usage at all. `split` does not duplicate frame data, it merely creates more references. And since all of the `overlay` filters are upstream of [out], they all consume both of their inputs before any forward progress can be made. So there is no filter in this graph that can buffer more than 1 frame. Actually, I would suspect memory usage to be slightly *lower* on average, because ff_filter_activate_default() first consumes all possible frames from input 1, then all possible frames from input 2, etc.; whereas FFFrameSync consumes from both inputs simultaneously. > > _______________________________________________ > 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".