Date: Sun, 6 Nov 2005 14:08:59 -0800 (PST) From: Arne "Wörner" <arne_woerner@yahoo.com> To: freebsd@sopwith.solgatos.com, freebsd-multimedia@freebsd.org, freebsd-firewire@freebsd.org Subject: Re: Sending DV to camcorder over firewire gives dropouts Message-ID: <20051106220859.52887.qmail@web30304.mail.mud.yahoo.com> In-Reply-To: <200511062139.VAA10645@sopwith.solgatos.com>
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Hi!
--- Dieter <freebsd@sopwith.solgatos.com> wrote:
> AMD64 running FreeBSD 6.0 beta3.
> Canon DV NTSC camcorder connected via firewire.
>
> Playing a tape and recording it on the computer via
>
> fwcontrol -R filename.dv
>
> appears to work fine.
>
Sweet...
(I am just watching "Dude! Where is my car?) :-))
> Sending the video back to the camcorder via
>
> fwcontrol -S filename.dv
>
> mostly works, but every 1.5-2 seconds or so I get a momentary
> dropout of both video and audio. I get the same dropouts
> with a dv file created by "fwcontrol -R" and with dv files
> created
> by ffmpeg.
>
> This is with the camcorder in "VCR" mode, and stopped (not
> recording).
> The computer is otherwise idle.
>
> The dropouts are very regular and repeatable, so it probably
> isn't due to
> an occasional transmission error, or the computer being busy for
> a moment.
>
> Wild Guess Theory #1:
>
> fwcontrol -S reports:
>
> 3948 frames, 131.50 secs, 30.02 frames/sec
> 784 frames, 25.92 secs, 30.24 frames/sec
> 3597 frames, 119.78 secs, 30.03 frames/sec
>
> Shouldn't this be 29.97 fps ?
>
I like that theory:
I found in ffmpeg's man page the following option:
-r fps
set frame rate (default = 25)
Dude! Did you use the "-r" option?
Maybe you could do some experiments:
1. -r 40
2. -r 25
3. -r 20
4. -r 30
and watch for the length of drop outs and inter-mittance-time (is
that the right word? I mean: The time between drop outs)...
-Arne
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