Date: Mon, 29 Mar 1999 11:06:22 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: roger@cs.strath.ac.uk (Roger Hardiman) Cc: crh@outpost.co.nz, kuku@gilberto.physik.RWTH-Aachen.DE, multimedia@FreeBSD.ORG Subject: Re: off topic - video compression .avi -> .mov Message-ID: <199903290906.LAA05627@labinfo.iet.unipi.it> In-Reply-To: <36FF60FC.2725D448@cs.strath.ac.uk> from "Roger Hardiman" at Mar 29, 99 12:15:53 pm
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> We did exactly this last week in our Telepresence Lab. > (Well, Jen did actually) couple of years ago, on a Pentium90 with a meteor, i hacked up things to dump an uncompressed video file to disk, and then ran mpeg_encode offline (i think i wrote a preprocessor so i could avoid using the PPM step). Because of various limitations, i could only manage to dump at CIF resolution, YUV422 and with a limited frame rate (disk throughput was around 3-4MB/s i think). I suppose with today's disks and 3.1 one might hope to reach some 7-8MB/s throughput on disk while capturing video, thus accomodating 640*480 YUV16 at 12.5 frames per second, or CIF at full frame rate. The reason you can't do this now is that as it is now the bt848 driver dumps everything to the same memory buffer so you risk overwriting an image while you are downloading it to disk. The meteor driver used multiple video buffers. luigi To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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