From owner-freebsd-multimedia@FreeBSD.ORG Tue Apr 18 08:54:19 2006 Return-Path: X-Original-To: freebsd-multimedia@FreeBSD.ORG 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 A6BFF16A400 for ; Tue, 18 Apr 2006 08:54:19 +0000 (UTC) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (lurza.secnetix.de [83.120.8.8]) by mx1.FreeBSD.org (Postfix) with ESMTP id EE50343D6E for ; Tue, 18 Apr 2006 08:54:16 +0000 (GMT) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (mhmdaz@localhost [127.0.0.1]) by lurza.secnetix.de (8.13.4/8.13.4) with ESMTP id k3I8sAgS049959 for ; Tue, 18 Apr 2006 10:54:15 +0200 (CEST) (envelope-from oliver.fromme@secnetix.de) Received: (from olli@localhost) by lurza.secnetix.de (8.13.4/8.13.1/Submit) id k3I8sAB7049958; Tue, 18 Apr 2006 10:54:10 +0200 (CEST) (envelope-from olli) Date: Tue, 18 Apr 2006 10:54:10 +0200 (CEST) Message-Id: <200604180854.k3I8sAB7049958@lurza.secnetix.de> From: Oliver Fromme To: freebsd-multimedia@FreeBSD.ORG In-Reply-To: X-Newsgroups: list.freebsd-multimedia User-Agent: tin/1.8.0-20051224 ("Ronay") (UNIX) (FreeBSD/4.11-STABLE (i386)) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.1.2 (lurza.secnetix.de [127.0.0.1]); Tue, 18 Apr 2006 10:54:15 +0200 (CEST) Cc: Subject: Re: ffmpeg question X-BeenThere: freebsd-multimedia@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: freebsd-multimedia@FreeBSD.ORG List-Id: Multimedia discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Apr 2006 08:54:19 -0000 Joe Auty wrote: > The cat command works perfectly, but I'm trying to script it, and > since you can use ffmpeg to specify how many seconds of footage to > capture I'm trying to make this work. #!/bin/sh - DURATION=20 DATESTAMP=$(date +%Y-%m-%d) cat /dev/whatever > /foo/bar-${DATESTAMP}.mpg & CATPID=$! sleep $DURATION kill $CATPID > According to Quicktime's Get Info, the cat files are mpeg2... Yes. What exactly is wrong with MPEG-2 in your opinion? > I'd like to know the best way to preserve the same quality > from the cat command using ffmpeg. ffmpeg decodes from MPEG format and then re-encodes it, which is lossy, so you can never preserver the same quality. That is, unless you use "copy" for the codec, which means it won't decode/encode anything -- but then it's just like teh cat command anyway, with a hundred times the overhead. > Am I starting to make sense now? I'm not sure. :-) Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. "And believe me, as a C++ programmer, I don't hesitate to question the decisions of language designers. After a decent amount of C++ exposure, Python's flaws seem ridiculously small." -- Ville Vainio