On Thu, Oct 14, 2010 at 12:05:09AM +0000, Jacob Meuser wrote:
quoted text
> On Thu, Oct 14, 2010 at 12:59:37AM +0200, Jan Stary wrote:
> > On Oct 13 22:07:27, Jacob Meuser wrote:
> > > On Wed, Oct 13, 2010 at 11:51:47PM +0200, Jan Stary wrote:
> > > > This is a fresh upgrade of current/amd64 on a Macbook3,1.
> > > > Basically, everything works except the wifi and uvideo.
> > > 
> > > > I installed the uvideo firmware as documented in uvideo(4).
> > > > I can capture an image with 'fswebcam image.jpg';
> > > > I have problems capturing a video stream with
> > > > ffmpeg -y -f video4linux2 -s vga -r 25 -i /dev/video0 /tmp/out.mpg
> > > > (the fps eventually drops to 0 and results in a tiny file
> > > > containing just a few frames) but I haven't really tried
> > > > tweaking the format options.
> > > 
> > > ffmpeg doesn't work with video(4).  frankly, I don't understand why
> > > video(4) support is enabled in ffmpeg, giving the the impression it's
> > > supposed to work, when it clearly doesn't.
> > 
> > On another machine (HP EliteBook 8530w running a recent -current)
> > I can capture video(4) just fine - using certain resolutions and frame
> > rates, that is.
> 
> with ffmpeg?  can you share your command, I've never gotten it to work.

fwiw, this is what I use, because using ffmpeg to capture directly from
video(4) has never worked for me:

$ video -f /dev/video1 -e yuy2 -s 640x480 -r 20 -o - | ffmpeg -y \
-f rawvideo -pix_fmt yuyv422 -s 640x480 -r 20 -i - \
-itsoffset 0.5 -f sndio -ar 16000 -ac 1 -i sun:1 out.avi

the audio is just slightly ahead (out of sync) without the -itsoffset.
the sndio backend in ffmpeg has fairly accurate timestamping; the
stamps should represent when the sound actually happened.  video(1) otoh
is just outputting a stream of raw frames, so ffmpeg assumes the
frames' timestamp is when they are read from stdin.  apparently on this
system with this camera it takes about a half second for images to be
captured and sent to stdout.

-- 
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