Date: 29 Jun 1999 13:30:10 +0200 From: Frode Vatvedt Fjeld <frodef@acm.org> To: freebsd-multimedia@freebsd.org Subject: Re: bt848 channel frequencies Message-ID: <2h3dzbs0ql.fsf@dslab7.cs.uit.no> In-Reply-To: Roger Hardiman's message of "Tue, 29 Jun 1999 11:42:34 %2B0100" References: <19990627074316.A1600@ipass.net> <199906272257.QAA07116@orthanc.ab.ca> <19990627194019.A1726@ipass.net> <2hzp1ksk05.fsf@dslab7.cs.uit.no> <37783907.94141BC7@cs.strath.ac.uk> <2h9093s4q3.fsf@dslab7.cs.uit.no> <3778A31A.794B@cs.strath.ac.uk>
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Roger Hardiman <roger@cs.strath.ac.uk> writes: > Well, you can use read(). It blocks on a frame (or a field). Hum.. I've always assumed that read() is a lot slower than mmap(), but I'm not really sure why. Do you think the performance of read() is comparable to mmap() etc.? > What is unstable in -stable? Right now, I can crash my machine with something like "cat file >/dev/fd0" (although this worked fine earlier this year). There's something wrong with the SYSVSHM code that causes a crash (very consistently) under certain conditions when there are no more SHM buffers. The meteor driver crashes consistently. I've submitted a pr with a fix many months ago, but nobody with CVS access seems to care (hence I'm not very eager to make more fixes). I'd guess this fix applies to meteor in -current too. > What [bktr] problems. Can you give some examples? I've not had any > problems myself with the API. Right now I observe this behavior in my app: This works (I get a working 768x576 YUV output): * Set size 384x288 and RGB format * Change size to 768x576 * Change format to YUV This doesn't work (the 768x576 YUV output is corrupted, mostly black with a green vertical bar to the right): * Set size 384x288 and YUV format (works) * Change size to 768x576 However, if i continue to do this: * Set format to RGB * Set format to YUV ..the 768x576 YUV output is fine again. I'm not 100% positive this is a fault in bktr, but, like I said, it is too hard to tell from the bktr source. And (almost) the same application code works fine with meteor. -- Frode Vatvedt Fjeld To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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