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 2077340E91 for ; Sun, 10 Jul 2022 17:16:38 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 54DAB68B988; Sun, 10 Jul 2022 20:16:36 +0300 (EEST) Received: from mail0.khirnov.net (red.khirnov.net [176.97.15.12]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 59E6A68B863 for ; Sun, 10 Jul 2022 20:16:30 +0300 (EEST) Received: from localhost (localhost [IPv6:::1]) by mail0.khirnov.net (Postfix) with ESMTP id F043C240179 for ; Sun, 10 Jul 2022 19:16:29 +0200 (CEST) Received: from mail0.khirnov.net ([IPv6:::1]) by localhost (mail0.khirnov.net [IPv6:::1]) (amavisd-new, port 10024) with ESMTP id D2WjYuAcdo06 for ; Sun, 10 Jul 2022 19:16:29 +0200 (CEST) Received: from lain.khirnov.net (lain.khirnov.net [IPv6:2001:67c:1138:4306::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "lain.khirnov.net", Issuer "smtp.khirnov.net SMTP CA" (verified OK)) by mail0.khirnov.net (Postfix) with ESMTPS id 73F792400F5 for ; Sun, 10 Jul 2022 19:16:29 +0200 (CEST) Received: by lain.khirnov.net (Postfix, from userid 1000) id 893E91601B2; Sun, 10 Jul 2022 19:16:29 +0200 (CEST) From: Anton Khirnov To: FFmpeg development discussions and patches In-Reply-To: References: <20220704162912.5577-1-ffmpeg@gyani.pro> <165718689777.31466.279724099132649515@lain.khirnov.net> Mail-Followup-To: FFmpeg development discussions and patches Date: Sun, 10 Jul 2022 19:16:29 +0200 Message-ID: <165747338953.25016.5154122227679155982@lain.khirnov.net> User-Agent: alot/0.8.1 MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] [PATCH v3] ffmpeg: add option -isync 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: Quoting Gyan Doshi (2022-07-08 05:56:21) > > > On 2022-07-07 03:11 pm, Anton Khirnov wrote: > > Quoting Gyan Doshi (2022-07-04 18:29:12) > >> This is a per-file input option that adjusts an input's timestamps > >> with reference to another input, so that emitted packet timestamps > >> account for the difference between the start times of the two inputs. > >> > >> Typical use case is to sync two or more live inputs such as from capture > >> devices. Both the target and reference input source timestamps should be > >> based on the same clock source. > >> > >> If not all inputs have timestamps, the wallclock times at the time of > >> reception of inputs shall be used. FFmpeg must have been compiled with > >> thread support for this last case. > > I'm wondering if simply using the other input's InputFile.ts_offset > > wouldn't achieve the same effect with much less complexity. > > That's what I initially did. But since the code can also use two other > sources for start times (start_time_realtime, first_pkt_wallclock), > those intervals may not exactly match the difference between > fmctx->start_times so I use a generic calculation. In what cases is it better to use either of those two other sources? As per the commit message, the timestamps of both inputs are supposed to come from the same clock. Then it seems to me that offsetting each of those streams by different amounts would break synchronization rather than improve it. -- Anton Khirnov _______________________________________________ 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".