Date: Thu, 6 Mar 1997 07:05:48 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: hasty@rah.star-gate.com (Amancio Hasty) Cc: tom@inna.net, smp@csn.net, jamie@inna.net, multimedia@freebsd.org Subject: Re: Video Capture for FreeBSD Message-ID: <199703060605.HAA15873@labinfo.iet.unipi.it> In-Reply-To: <199703060618.WAA00815@rah.star-gate.com> from "Amancio Hasty" at Mar 5, 97 10:18:37 pm
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> Try compiling rgb16 as:
>
> cc -o rgb16 -m486 -O2 rgb.c
nope, the trick is buffering data before writing:
> > for (c = 0 ; c < ROWS*COLS; c++) {
> > b[0]= ((*rgb16 >> 7) & 0xf8); /* r */
> > b[1]= ((*rgb16 >> 2) & 0xf8); /* g */
> > b[2]= ((*rgb16++ << 3) & 0xf8); /* b */
> > write(o, &b[0], 3);
this one issues a system call for each pixel (3 bytes of output!).
Luigi
-----------------------------+--------------------------------------
Luigi Rizzo | Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it | Universita' di Pisa
tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/
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