From owner-freebsd-multimedia Thu Jan 9 10:22:59 2003 Delivered-To: freebsd-multimedia@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 573F337B401 for ; Thu, 9 Jan 2003 10:22:57 -0800 (PST) Received: from smtp6.wanadoo.nl (smtp6.wanadoo.nl [194.134.35.177]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5888F43F13 for ; Thu, 9 Jan 2003 10:22:56 -0800 (PST) (envelope-from steve@sohara.org) Received: from ams-gw.sohara.org (p2486.vwr.wanadoo.nl [194.134.217.191]) by smtp6.wanadoo.nl (Postfix) with SMTP id 872796F123; Thu, 9 Jan 2003 19:22:52 +0100 (CET) Date: Thu, 9 Jan 2003 19:22:47 +0100 From: Steve O'Hara-Smith To: Andre Albsmeier Cc: freebsd-multimedia@FreeBSD.ORG Subject: AV sync on ffmpeg captures - was Re: FreeBSD 4.7R: no sound when recording with ffmpeg? Message-Id: <20030109192247.0602e203.steve@sohara.org> In-Reply-To: <20030109144913.A30175@curry.mchp.siemens.de> References: <20021028202230.1283e8cd.steve@sohara.org> <20021029194220.7fb532ad.steve@sohara.org> <20030106115851.A12349@curry.mchp.siemens.de> <20030106215821.60130d42.steve@sohara.org> <20030107085526.A14263@curry.mchp.siemens.de> <20030107191359.12abeb78.steve@sohara.org> <20030109144913.A30175@curry.mchp.siemens.de> X-Mailer: Sylpheed version 0.8.8 (GTK+ 1.2.10; i386-portbld-freebsd4.7) X-Face: %]+HVL}K`P8>+8ZcY-WGHP6j@&mxMo9JH6_WdgIgUGH)JX/usO0%jy7T~IVgqjumD^OBqX,Kv^- GM6mlw(fI^$"QRKyZ$?xx/ Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-multimedia@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Thu, 9 Jan 2003 14:49:13 +0100 Andre Albsmeier wrote: AA> On Tue, 07-Jan-2003 at 19:13:59 +0100, Steve O'Hara-Smith wrote: AA> > On Tue, 7 Jan 2003 08:55:26 +0100 AA> > Please do, it would be good to confirm that the problem is not in AA> > mplayer (I suspect it isn't but confirmation is good and I have no AA> > windows). AA> AA> Hmm, tried the file in question with "Zoom Player" under Win32 and AA> here the sync is perfect! So far so good, now one would say this is an AA> mplayer problem. But there are two things left: AA> AA> 1.) I played lot of other mpegs using mplayer and the audio sync is AA> ok. Yep - I've played a lot of VOBs and AVIs in mplayer without sync problems too. Timestamping in streams is an amazingly complex thing (ie. I haven't managed to grok it yet). There are AFAICT multiple ways to work out when things should be played, there is probably a consistency problem in the streams generated by ffmpeg. What this tells me is that I shouldn't try and fix this in the grab code which is probably behaving well now, it needs fixing in the ffmpeg stream building code (somewhere) which I don't understand properly (the last time I tried to fiddle with it strange and unexpected things happened, I retreated in confusion). It may be better in ffmpeg 0.46 unfortunately the performance of 0.46 leaves much to be desired - my XP can't quite keep up with half resolution recording under 0.46 :(. AA> 2.) When I use Virtualdub (which also runs under Win32 and has nothing AA> to AA> do with mplayer) It probably digs out the timing in the same way as mplayer. What happens if you just play back the stream with mplayer -fps 25.045 (or perhaps about 24.95) ? Can anyone point me to a comprehensible description of how the timestamping is supposed to work in mpeg and avi streams ? If I can grok what is supposed to be going on I can take a crack at fixing it. -- C:>WIN | Directable Mirrors The computer obeys and wins. |A Better Way To Focus The Sun You lose and Bill collects. | licenses available - see: | http://www.sohara.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message