Try following ;
 
 gst-launch v4l2src device=/dev/video0 !
'video/x-raw-yuv,width=386,height=386,framerate=30/1' ! ffmpegcolorspace  !
videomixer name=mix !  ffmpegcolorspace  ! xvimagesink filesrc location=crosshair.png ! pngdec !
ffmpegcolorspace ! 'video/x-raw-yuv,format=(fourcc)AYUV,width=386,height=386,framerate=30/1'  ! freeze  ! mix

On Wed, Mar 31, 2010 at 9:32 AM, Vogan <vaughan@infact.co.nz> wrote:

Hi

Thanks for the help, I am now trying this

gst-launch v4l2src device=/dev/video0 !
'video/x-raw-yuv,width=320,height=240,framerate=30/1' ! ffmpegcolorspace  !
videomixer name=mix ! xvimagesink filesrc location=crosshair.png ! pngdec !
ffmpegcolorspace ! freeze ! mix.

and are getting the following error once the pipeline has started

ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Internal
data flow error.
Additional debug info:
gstbasesrc.c(2234): gst_base_src_loop ():
/GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
streaming task paused, reason not-negotiated (-4)

The image I am trying to overlay has a transparent background and is 386x386
pixels.

Any ideas?

Vaughan


sudarshan bisht wrote:
>
> Hi ,
>
>  videomixer works on AYUV ( that means yuv data having alpha values for
> transparency ) and pngdec  gives RGB data , that's why these two elements
>  are not linking .
>
> Try putting ffmpegcolorspcae after pngdec .
>
> On Wed, Mar 31, 2010 at 12:58 AM, Vogan <vaughan@infact.co.nz> wrote:
>
>>
>> Hi
>>
>> I am wanting to overlay an image (crosshairs inthis case) on top of a
>> stream
>> from a web cam.  The image is a png file with a transparent background.
>>  The
>> pipeline I have tried is
>>
>> gst-launch v4l2src device=/dev/video0 !
>> 'video/x-raw-yuv,width=640,height=480,framerate=30/1' ! videomixer
>> name=mix
>> ! xvimagesink ! filesrc location=crosshair.png ! pngdec ! mix.
>>
>> When I try to run this I get WARNING: erroneous pipeline: could not link
>> pngdec0 to mix
>>
>> Any hints on what I am doing wrong? or is it simply not possible to
>> overlay
>> a static image on a live stream?
>>
>> Vaughan
>>
>> --
>> View this message in context:
>> http://n4.nabble.com/Overlaying-an-image-on-a-live-stream-tp1745726p1745726.html
>> Sent from the GStreamer-devel mailing list archive at Nabble.com.
>>
>>
>> ------------------------------------------------------------------------------
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>
>
>
> --
> Regards,
>
> Sudarshan Bisht
>
> ------------------------------------------------------------------------------
> Download Intel&#174; Parallel Studio Eval
> Try the new software tools for yourself. Speed compiling, find bugs
> proactively, and fine-tune applications for parallel performance.
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View this message in context: http://n4.nabble.com/Overlaying-an-image-on-a-live-stream-tp1745726p1746276.html
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------------------------------------------------------------------------------
Download Intel&#174; Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
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Regards,

Sudarshan Bisht