GStreamer

Hi,

On Wed, Feb 9, 2011 at 9:17 PM, Will Kelleher <will.kelleher@...> wrote:
> Hi everyone,
>
> I've been trying to use my TI Davinci hardware as a USB webcam gadget.
>  I backported the webcam module to the 2.6.32 kernel and I can
> compile/load it successfully.  This module creates a v4l2 output
> device that can accept YUY2 and MJPEG formats.
>
> When I run
>
> gst-launch videotestsrc ! v4l2sink device=/dev/video1
>
> I get
>
> "ERROR: from element
> /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0: Could not
> negotiate format"

probably you need to convert format/resolution/frame rate. If you want
to know what went wrong with your caps negotiation, use -m as an
option for gst-launch. If you want even more details, you can set
GST_DEBUG=GST_CAPS:3 (or more).

A a last note, adding an ffmpegcolorspace ! videoscale ! videorate (or
a subet of the pipe) may help you.

Regard

>
> I've tried a variety of other pipelines but they all produce the same error.
>
> Does anyone have experience with sending output to this particular
> module (g_webcam)?  Am I doing something obviously wrong?
>
> Thanks,
>
> Will Kelleher
> Nuvixa, Inc.
>
> ------------------------------------------------------------------------------
> The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
> Pinpoint memory and threading errors before they happen.
> Find and fix more than 250 security defects in the development cycle.
> Locate bottlenecks in serial and parallel code that limit performance.
> http://p.sf.net/sfu/intel-dev2devfeb
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel@...
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
>

On Thu, Feb 10, 2011 at 09:15:49AM +0200, Marco Ballesio wrote:
> Hi,
> 
> On Wed, Feb 9, 2011 at 9:17 PM, Will Kelleher <will.kelleher@...> wrote:
> > Hi everyone,
> >
> > I've been trying to use my TI Davinci hardware as a USB webcam gadget.
> >  I backported the webcam module to the 2.6.32 kernel and I can
> > compile/load it successfully.  This module creates a v4l2 output
> > device that can accept YUY2 and MJPEG formats.
> >
> > When I run
> >
> > gst-launch videotestsrc ! v4l2sink device=/dev/video1
> >
> > I get
> >
> > "ERROR: from element
> > /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0: Could not
> > negotiate format"
> 
> probably you need to convert format/resolution/frame rate. If you want
> to know what went wrong with your caps negotiation, use -m as an
> option for gst-launch. If you want even more details, you can set
> GST_DEBUG=GST_CAPS:3 (or more).

You're much better off debugging caps negotiation problems using:

  GST_DEBUG=capsdebug:3 gst-launch videotestsrc ! capsdebug ! v4l2sink



David

On Wed, Feb 9, 2011 at 1:17 PM, Will Kelleher <will.kelleher@...> wrote:
> Hi everyone,
>
> I've been trying to use my TI Davinci hardware as a USB webcam gadget.
>  I backported the webcam module to the 2.6.32 kernel and I can
> compile/load it successfully.  This module creates a v4l2 output
> device that can accept YUY2 and MJPEG formats.
>
> When I run
>
> gst-launch videotestsrc ! v4l2sink device=/dev/video1
>

so maybe I am missing something here, but if it is a camera/input
device, I think you probably want to use v4l2src..  since v4l2sink is
for output (tv tuners, or hw overlay on some platforms)

ie. something like: gst-launch v4l2src ! autovideosink

BR,
-R



> I get
>
> "ERROR: from element
> /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0: Could not
> negotiate format"
>
> I've tried a variety of other pipelines but they all produce the same error.
>
> Does anyone have experience with sending output to this particular
> module (g_webcam)?  Am I doing something obviously wrong?
>
> Thanks,
>
> Will Kelleher
> Nuvixa, Inc.
>
> ------------------------------------------------------------------------------
> The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE:
> Pinpoint memory and threading errors before they happen.
> Find and fix more than 250 security defects in the development cycle.
> Locate bottlenecks in serial and parallel code that limit performance.
> http://p.sf.net/sfu/intel-dev2devfeb
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel@...
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel
>