Date: Wed, 17 May 2000 11:37:04 -0700 (PDT) From: just matt <matt@dqc.org> To: freebsd-multimedia@FreeBSD.ORG Subject: Re: video recording and encoding on FreeBSD Message-ID: <Pine.BSO.4.21.0005171115030.28055-100000@dqc.org> In-Reply-To: <3922B687.BD179A77@intercom.com>
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> > How much diskspace would you require for an hour and a reasonable quality? > > I think 90 to 120 minutes of video take a very huge amount of temporary > > space and encoding even on a "fast" PC, say 600 MHz PIII, what seems a > > good machine for home use, would take more than "just a few hours" or > > overnight. > Hrm, yes, that would take a huge amount of space. It's roughly 3 gigs per 10 minutes, so 9 x 3 = 27 gigs for 90 minutes, but you still need space to hold the mpeg video stream + raw audio data + compressed audio data on top of the 27 gigs for the 90 minutes of the raw AV stream just do to the way fxtv compresses things. For a Video CD quality stream, the multiplexed mpeg file should be aprox 1hr per cd, or 300-325MB per half hour. If the stream size is not even clsoe to that, then something is wrong. As far as encoding time, it's not too bad, but it takes several hours (4-5) to encode 10 minutes worth on my p233. It's usually the space req's that are the problem. It's worth playing around with if you have all the hardware just sitting there already, but I wouldn't advise blowing a lot of money on big fast disks thinking things will work perfectly. I've been mucking with mpeg-1 encoding under freebsd since last fall, and I have yet to get one encoded stream that conforms to the mpeg-1 standard closely enough to not have problems. I mean, for short clips like 5 minutes or so, the streams ran fine \w the MpegTV player or windows media player, but other players typically crashed or wouldn't work, windows based mpeg-1 editors (real expensive stuff, not dinky shareware) wouldn't edit any of the streams and gave me all sorts of hideous errors, and with any stream longer than 8 minutes mpegTV and the windows media player would freeze. No matter what the length none of the streams would play anything more than audio through my hardware mpeg-1 decoder. So, a word to the wise, don't expect perfect results from the process. Things prolly won't get fine tuned until someone can land a copy of the IEC mpeg-1 standard papers, but those cost over $400 USD so... I've already ranted about this in the past so I'll stop now. I'm supposed to get a low end hardware mpeg-1 encoder come this friday, and perhaps it it performs admirably under windows come vacation time in Jul/Aug I may start exploring ways to integrate it into bsd, but... we'll see how it performs first. I'm hoping the quality of the streams it will produce will be on par (or close) to that of the professional vcd's. Not to knock mpeg_encode, as it makes a much better picture than that stupid Xing encoder or other windoze encoders, but the picture quality is not that of a professionally mastered mpeg-1 stream on a vcd. That and I really want some long mpeg-1 streams that comply enough to standards such that they will work in hardware decoders and a wider variety of software decoders. - Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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