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 F408443044 for ; Tue, 19 Jul 2022 07:06:51 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 7856B68B58F; Tue, 19 Jul 2022 10:06:48 +0300 (EEST) Received: from smtp-out6.electric.net (smtp-out6.electric.net [192.162.217.187]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 8E2B968B54C for ; Tue, 19 Jul 2022 10:06:41 +0300 (EEST) Received: from 1oDhJY-000545-Uc by out6e.electric.net with emc1-ok (Exim 4.94.2) (envelope-from ) id 1oDhJY-00055A-Vd for ffmpeg-devel@ffmpeg.org; Tue, 19 Jul 2022 00:06:40 -0700 Received: by emcmailer; Tue, 19 Jul 2022 00:06:40 -0700 Received: from [212.161.31.33] (helo=SS-XFILES1.bfi.org.uk) by out6e.electric.net with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1oDhJY-000545-Uc for ffmpeg-devel@ffmpeg.org; Tue, 19 Jul 2022 00:06:40 -0700 Received: from SS-XFILES1.bfi.org.uk (172.16.5.104) by SS-XFILES1.bfi.org.uk (172.16.5.104) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.6; Tue, 19 Jul 2022 08:06:40 +0100 Received: from SS-XFILES1.bfi.org.uk ([fe80::c0f5:c4c5:8260:5e4f]) by SS-XFILES1.bfi.org.uk ([fe80::c0f5:c4c5:8260:5e4f%6]) with mapi id 15.01.2507.006; Tue, 19 Jul 2022 08:06:40 +0100 From: Stephen McConnachie To: FFmpeg development discussions and patches Thread-Topic: [FFmpeg-devel] Development opportunity: LTC noise on files created from videotape source: filter idea Thread-Index: AQHYmsnMXqtm8VxCQM+vbQ1ygjqbs62FQ1tg Date: Tue, 19 Jul 2022 07:06:40 +0000 Message-ID: <89f4bd657bc94788aacfd85c4ff1e6cb@bfi.org.uk> References: <53e29d553f5944a5b0aaa75c7fa48bc1@bfi.org.uk> <20220718171412.GS2088045@pb2> In-Reply-To: <20220718171412.GS2088045@pb2> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.16.5.199] X-Outbound-IP: 212.161.31.33 X-Env-From: Stephen.McConnachie@bfi.org.uk X-Proto: esmtps X-Revdns: stargate.bfi.org.uk X-HELO: SS-XFILES1.bfi.org.uk X-TLS: TLS1.2:ECDHE-RSA-AES128-GCM-SHA256:128 X-Authenticated_ID: X-PolicySMART: 3432616, 27538057, 23552168 MIME-Version: 1.0 Content-Language: en-US X-Virus-Status: Scanned by VirusSMART (c) X-Virus-Status: Scanned by VirusSMART (b) X-PolicySMART: 3432616, 27538057, 23552168 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=bfi.org.uk; s=bfiselector01; h=MIME-Version:In-Reply-To:References:Message-ID:Date:To:From; bh=LyQuVFYRaDLr/3bZgGa6xVAe9xoRwh8KDQMQbq/Bhm4=; b=mCgJBXqvRqFDS4pkg5fK13l7EBi39E2M8HRe5Cl1rHdp1EIf/vo/VUS27DWU4K00zfARzxUpjoWw0vdbbH8ZtkMme/auvLtkLSKGh0Zty0aXqCMprjb8TfR9Q33DXNW1BF3U3lgEZHgHiYdwc0U6HzgSEnEWAThd2Xm3iALUKjoCxlWfnfGooy9L/qmI13NeP0AVi+f2tsThxCnQDJGgToxDuX8dhqW48LjU/vKN0+zoNVwGS4wVRVAyJ5jyiVB7AmMLsZiREpi8V6wYMIw/6gspTVzivhCRxu9AVOTGYr0olJ/+mxCEv7YM5f+0mUmO2MNXyHu2U0zid0NIoYpyfA==; Subject: Re: [FFmpeg-devel] Development opportunity: LTC noise on files created from videotape source: filter idea 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: > It should be possible to implement a LTC decoder that turns a audio track into LTC binary data. If that succeeded and the data is valid then teh track would very likely have contained LTC. I was hoping that would be achievable, thank you Michael. For context, this site has a pretty good explanation of LTC - http://www.philrees.co.uk/articles/timecode.htm >Do i understand correctly that the tracks are LTC or normal audio not mixed? >or are there tracks that mix audio and LTC and require seperation ? Yes your understanding is accurate - the LTC and the other audio (Mix / FX) tracks are discrete, not mixed - and in the encoding to FFV1 MKV the LTC-derived stream is a discrete stream. >I think there are several developers who could develop such filter. >I could do it, Iam sure paul could do as well. Thank you! Dave Rice explained that he had made a start on this idea, and asked me for samples of files with LTC-derived audio - I will send Dave samples, and come back to you if I need to explore other options too. Cheers, Stephen -----Original Message----- From: ffmpeg-devel On Behalf Of Michael Niedermayer Sent: 18 July 2022 18:14 To: FFmpeg development discussions and patches Subject: Re: [FFmpeg-devel] Development opportunity: LTC noise on files created from videotape source: filter idea Attention. This email originated outside the BFI. Please be extra vigilant when opening attachments or clicking links. On Mon, Jul 18, 2022 at 09:53:14AM +0000, Stephen McConnachie wrote: > Hi FFMPEG developers, > > I have a proposal for a paid development opportunity to add a filter to FFMPEG. > > I followed the advice on the FFMPEG Consulting page at https://ffmpeg.org/consulting.html and am emailing this list to try to identify if any of the FFMPEG developers may be able to take on a development commission. > > Background: we are digitising high volumes of videotape carriers, and have identified a common case in some videotape formats where Linear Time Code from the tape carrier is present on audio stream 1 in the encoded file - manifesting as a continuous noise. > > Idea: could a filter be developed in FFMPEG, based on example files we can provide, to identify the presence of an LTC-derived audio stream, and additionally identify which of the streams is the LTC stream. > > If this filter idea sounds achievable, I would aim to identify which of the FFMPEG developers may be able to take on this work, and estimated costs and timeline. It should be possible to implement a LTC decoder that turns a audio track into LTC binary data. If that succeeded and the data is valid then teh track would very likely have contained LTC. Do i understand correctly that the tracks are LTC or normal audio not mixed? or are there tracks that mix audio and LTC and require seperation ? I think there are several developers who could develop such filter. I could do it, Iam sure paul could do as well. thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB "I am not trying to be anyone's saviour, I'm trying to think about the future and not be sad" - Elon Musk The British Film Institute is governed by Royal Charter and is a charity registered in England and Wales number 287780. The contents of this e-mail are confidential and may be legally privileged. If you are not the intended recipient, kindly notify the sender that you have received this message in error and immediately delete it. 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