From owner-freebsd-multimedia Sat Mar 16 5:54:59 2002 Delivered-To: freebsd-multimedia@freebsd.org Received: from smtp2.wanadoo.nl (smtp2.wanadoo.nl [194.134.35.138]) by hub.freebsd.org (Postfix) with ESMTP id 217A637B416 for ; Sat, 16 Mar 2002 05:54:55 -0800 (PST) Received: from ams-gw.sohara.org (p2464.vwr.wanadoo.nl [194.134.217.169]) by smtp2.wanadoo.nl (8.11.3/8.11.3) with SMTP id g2GDshJ11030; Sat, 16 Mar 2002 14:54:43 +0100 (MET) Date: Sat, 16 Mar 2002 14:54:38 +0100 From: "Steve O'Hara-Smith" To: Mike Meyer Cc: freebsd-multimedia@freebsd.org Subject: Re: Some video Capture questions (Was: Some audio capture questions) Message-Id: <20020316145438.7695fac0.steve@sohara.org> In-Reply-To: <15507.9577.337812.353727@guru.mired.org> References: <20020315074048.A12682@hostwiththemost> <15506.40571.544247.899130@guru.mired.org> <20020316084125.3b2b0874.steve@sohara.org> <15507.9577.337812.353727@guru.mired.org> X-Mailer: Sylpheed version 0.7.3 (GTK+ 1.2.10; i386-portbld-freebsd4.5) 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 Sat, 16 Mar 2002 04:58:49 -0600 Mike Meyer wrote: MM> Since you seem to have a grasp of these numbers, let me ask this one: I'm getting a grasp for them :) MM> I've got two machines, A and B. B has enough oomph to capture MM> real-time video - it's done it. B doesn't, or at least didn't when I MM> tried using MS's software on it without tuning. However, the video MM> feed of interest is tied to B. How much oomph does B need in order to MM> get the bits to A to capture them? I don't need on-the-fly encoding, MM> so I'll give it up to get good quality. Hmm there's a good one. It all comes down to byte shuffling bandwidth though. First biggie is full resolution (640x480 for NTSC or 768x576 PAL) or half resolution. All real time video handling I've seen going to date has been in half res - (full res is rather a lot of bps ~30Mbyte/sec for RGB24 or ~20Mbtye for most useful YUV formats). This is too much for nearly all systems - going to half res quarters the bandwidth (5-7.5Mbytes per second). So as long as you have enough oomph to saturate a 100BaseT from memory there should be enough oomph to handle realtime video capture and dump to LAN (as long as nothing else is happening). If you want full resolution though that had better be a gigbit ethernet and enough oomph to half saturate it from RAM. MM> Between them is a 100BaseT network and a switch. I can put a second MM> ethernet card in B and move the link from A to that instead of the MM> switch if required, but I don't think it's required. It may well be - you want at least half the bandwidth for uncompressed video. MM> I'm already doing this with audio to play it on A with esound, just by MM> doing "ssh -n B esdrec | esdcat" on A. Is there a similar tool for MM> video? Well, a similar tool that will work with the ATI AIW? Or should Look into ffmpeg - the capture isn't working properly yet (audio slips terribly and my bt848 driver is still a hack) but the streaming server stuff seems to be good. -- 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