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 316B142C0B for ; Fri, 1 Jul 2022 11:03:30 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 2778668B78D; Fri, 1 Jul 2022 14:03:28 +0300 (EEST) Received: from mout-p-201.mailbox.org (mout-p-201.mailbox.org [80.241.56.171]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id E75CB68B325 for ; Fri, 1 Jul 2022 14:03:19 +0300 (EEST) Received: from smtp102.mailbox.org (smtp102.mailbox.org [10.196.197.102]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 4LZC3m5dwgz9sRx for ; Fri, 1 Jul 2022 13:03:16 +0200 (CEST) Message-ID: <5d033e8d-0cb4-fdae-aed7-e76c8f639f6d@gyani.pro> Date: Fri, 1 Jul 2022 16:33:04 +0530 MIME-Version: 1.0 Content-Language: en-US To: ffmpeg-devel@ffmpeg.org References: <20220625082951.11897-1-ffmpeg@gyani.pro> <20220625082951.11897-2-ffmpeg@gyani.pro> <165666982804.10358.9258749207970028711@lain.khirnov.net> From: Gyan Doshi In-Reply-To: <165666982804.10358.9258749207970028711@lain.khirnov.net> Subject: Re: [FFmpeg-devel] [PATCH v2 2/2] 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-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: On 2022-07-01 03:33 pm, Anton Khirnov wrote: > Quoting Gyan Doshi (2022-06-25 10:29:51) >> 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 both streams are using the same clock, then why is any extra > synchronization needed? Because ffmpeg.c normalizes timestamps by default. We can keep timestamps using -copyts, but these inputs are usually preprocessed using single-input filters which won't have access to the reference inputs, or the merge filters like e.g. amix don't sync by timestamp. What this option does is allow keeping 0-start timestamps but offset the target input relatively. Then it's possible to filter/merge in sync. Regards, Gyan _______________________________________________ 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".