Date: Mon, 21 Feb 2005 10:44:23 +0000 From: Steve O'Hara-Smith <steve@sohara.org> To: Paul Chvostek <paul+fbsd@it.ca> Cc: freebsd-multimedia@freebsd.org Subject: Re: ffmpeg at half speed ... sort of. Message-ID: <20050221104423.24956bf7.steve@sohara.org> In-Reply-To: <20050218145654.GA31961@it.ca> References: <20050207032841.GA33816@it.ca> <20050207100521.544ed9bc.steve@sohara.org> <20050209180336.GA28606@it.ca> <20050210095713.3b155ce6.steve@sohara.org> <20050213182120.GT40151@it.ca> <20050214102331.0380d1b8.steve@sohara.org> <20050218145654.GA31961@it.ca>
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On Fri, 18 Feb 2005 09:56:55 -0500
Paul Chvostek <paul+fbsd@it.ca> wrote:
> So ... if the same video signal and same hardware shows these wildly
> inconsistent framerates encoding with ffmpeg in FreeBSD but not in
> Fedora, it's likely a problem in the bktr driver?
No I think it's in the low level timekeeping that usleep uses
rather than anything specific to bktr. There isn't much around that I
know of other than video capture that is particularly sensitive to
accurate usleep though. I rather suspect ACPI is screwing up fine
timekeeping. The Linux grab code also uses a timer fallback for missed
sync signals (it's a pretty common problem) but is less noisy about it
than my BSD grab code in ffmpeg.
> I get the same behaviour with multiple video sources (both analog and
> digital satellite video decoders, a handycam, a VCR, various cables) and
> multiple encoder cards (AVerMedia cx878 and an old Intel bt848) ... and
> of course, as I said, the problem seems exclusive to FreeBSD (tested
> with both 4.11 and 5.3).
Do both 4.11 and 5.3 crash with ACPI disabled ?
> > kern.timecounter.hardware should be the one - from the looks of it. Try setting
> > it to TSC or i8254 (probably TSC will do a better job).
>
> Tried both, to no avail; the symptoms remain.
In a word ... bugger!
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