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Date:      Wed, 16 Nov 2005 15:33:09 +1030
From:      "Daniel O'Connor" <doconnor@gsoft.com.au>
To:        Danny Pansters <danny@ricin.com>
Cc:        freebsd-stable@freebsd.org, Miguel Mendez <mmendez@gmail.com>
Subject:   Re: mplayer + bktr
Message-ID:  <200511161533.10818.doconnor@gsoft.com.au>
In-Reply-To: <200511140221.54069.danny@ricin.com>
References:  <200511132204.55664.doconnor@gsoft.com.au> <200511141132.04513.doconnor@gsoft.com.au> <200511140221.54069.danny@ricin.com>

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On Mon, 14 Nov 2005 12:51, Danny Pansters wrote:
> I myself am not really doing anything with capturing, but some ideas that
> may be helpful:
>
> FWIW, from what I know in ring capture mode the video gets synch'd by the
> audio by having enough frames per audio sample. So if audio sample size or
> expected speed or expected kHz is somehow wrong...

Hmm..
Certainly worth instrumenting.. Although wading through the mplayer source =
is=20
always an 'interesting' experience :)

> Also the code for ring capture mode (as opposed to immediate which does n=
ot
> do audio but does give a video one could capture at 25 fps) has its own
> timing (perhaps it uses rtc down the line, I dunno, is rtc.ko alright?).
> You may get into a worst-worst-worst-even worst scenario where the softwa=
re
> timer degrades on and on possibly.

=46reeBSD doesn't have rtc.ko.. Mine doesn't anyway :)

I'm not sure how mplayer in FreeBSD stamps frames either.

> Maybe capturing only works well if you use immediate (case 2 in bktr(4)
> IIRC) and you should capture audio seperately and later merge them to
> frames.

Hmm, well in any capture you're going to have to worry about clock drift=20
(between the sound card and the bktr card) and dropped frames.

> > > > I don't use either of those, but a small program I wrote which
> > > > captures YUV frames and uses the Xv extension doesn't show the
> > > > problem.
>
> Capturing only pictures at 25 fps (with mplayer vo) can be handled easily.

Hmm OK.

So much to learn! :)

=2D-=20
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C

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