[MPlayer-users] My cropping question revisited.

Gene Heskett gheskett at wdtv.com
Thu Sep 26 23:04:19 CEST 2013

On Thursday 26 September 2013 16:53:52 Reimar Döffinger did opine:

> On 26.09.2013, at 22:37, Reimar Dأ¶ffinger <Reimar.Doeffinger at gmx.de> 
> > On 25.09.2013, at 23:52, Gene Heskett <gheskett at wdtv.com> wrote:
> >> I did some fiddling 2 days back, before I tore up a knee and am
> >> reduced to using crutches to get around.
> > 
> > Hope you'll manage to get rid of those crutches soon!
> > 
> >> 1, mplayer idents the camera ok, but cannot connect.
> >> 
> >> Its identified in the log as input: HD Pro Webcam C920 as
> >> /devices/pci0000:00/0000:00:1d.7/usb1/1-6/1-6:1.0/input/input10
> >> And seems to claim its a 2304 by 2xxx pixel device.
> > 
> > Unless someone managed to get MPlayer to work with exactly that card,
> > I think you'd need to give us the exact and complete MPlayer output to
> > start. (and yes, updating to latest SVN does not hurt either).
> > 
> >> 2, it would appear that libv4lconvert.so may be one of the stumbling
> >> blocks.
> > 
> > For many webcams MPlayer should not need it, since it can do the
> > necessary conversion, at most it needs to be told how to figure out
> > which to use.
> > Though if you are unlucky it might indeed be one of the cams that
> > simply don't work with MPlayer.
> This:
> http://www.oz9aec.net/index.php/gstreamer/473-using-the-logitech-c920-w
> ebcam-with-gstreamer
> Tells me the camera can do yuv, h.264 and mjpeg.

And those formats are exactly the ones that return a black screen.  I 
thought it odd that no format of yuv or mjpeg worked.  There is also a 
lengthy list of "unidentified" formats which only return the pixel x pixel 
size but give black screens with libv4lconvert, an older version in the 
processing chain that camunits uses.  What other names might h.264 be known 
as to a library built in 2010?  Or is that too new for that time frame?

> MPlayer can do all of them without libv4lconvert.

One of the reasons I'd like to see it working.

> Which one is best depends on the ratio USB bandwidth/cpu power
> available. I also have to admit I don't know how to tell MPlayer which
> one to select.

Obviously neither do I...  CPU power available is likely a problem since 
this portion of the software runs on a single core of the dual core an atom 
has, at 1.6ghz IIRC.  IOW, it does everything but actually drive the 

Thank you Reimar.

Cheers, Gene
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