Date: Sat, 16 Mar 2002 11:08:50 -0600 From: Mike Meyer <mwm-dated-1016730531.2a6414@mired.org> To: "Steve O'Hara-Smith" <steve@sohara.org> Cc: freebsd-multimedia@freebsd.org Subject: Re: Some video Capture questions (Was: Some audio capture questions) Message-ID: <15507.31778.986659.728170@guru.mired.org> In-Reply-To: <20020316145438.7695fac0.steve@sohara.org> References: <20020315074048.A12682@hostwiththemost> <15506.40571.544247.899130@guru.mired.org> <20020316084125.3b2b0874.steve@sohara.org> <15507.9577.337812.353727@guru.mired.org> <20020316145438.7695fac0.steve@sohara.org>
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In <20020316145438.7695fac0.steve@sohara.org>, Steve O'Hara-Smith <steve@sohara.org> typed: > On Sat, 16 Mar 2002 04:58:49 -0600 > 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). I'm turning the things into VCDs, so most of it is at 352x240. > 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. Sounds like I'll need more like 1/6th, which is still pushing it, but may well work. I'll have to give it a try. > 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. Unfortunately, the capture box has a ATI AIW in it. So the big question about saturating the bandwidth is "Can Windows/Linux do it." Thanx, <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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