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gst-launch v4l2src with MJPG format

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John Buckley

gst-launch v4l2src with MJPG format

This post was updated on .

Hello,
I have the "approved" USB webcam (Creative Optia AF) and I want to use GStreamer to stream the video to an XWindow.

I have the uvcvideo module loaded and /dev/video0 is present.

I am running openembedded on the Gumstix Verdex Pro XL6P.
This is what I see when I plug the camera in...

root@gumstix-custom-verdex:~# usb 1-2: new full speed USB device using pxa27x-ohci and address 4
usb 1-2: configuration #1 chosen from 1 choice
uvcvideo: Found UVC 1.00 device VF0560 Live! Cam Optia AF (041e:406d)
input: VF0560 Live! Cam Optia AF as /devices/platform/pxa27x-ohci/usb1/1-2/1-2:1.0/input/input3
4:3:1: cannot get freq at ep 0x84

The videotestsrc element works fine with ximagesink.

I have made some progress over the last few days. I have tried to load luvcview and v4l-info on the Gumstix with no luck. Is there a way to view the parameters of my camera? The manufacturer doesn't seem to provide any of this info.

Also, I saw another message that says this particular camera is coming up with 2 different ID#s. 041e:4058 is in the approved camera list and mine cimes up with 041e:406d. That's confusing.

I think I'm on the verge of success. I can get the video input to start rolling without error using the MJPG format:
gst-launch v4l2src ! image/jpeg,width=320,framerate=15/1,rate=15 ! fakesink.

But now I can't get it to output to ximagesink. I've seen some references to using:
gst-launch v4l2src ! image/jpeg,width=320,framerate=15/1,rate=15 ! jpegdec ! ffmpegcolorspace ! ximagesink.

I've loaded gst-plugins-good but I can't get the jpegdec element to appear in the gst-inspect list. I've tried deleting and recreating the ~/.gstreamer-0.10 file/folder and running gst-inspect again but that doesn't work.

Any help would be greatly appreciated...
Thanks,
John Buckley

Wim Taymans

Re: v4l2src0: Could not negotiate format

On Sat, 2009-10-31 at 14:51 -0700, John Buckley wrote:

> Hello,
> I've been trying to get an approved USB webcam (Creative Optia AF) to run
> using GStreamer and sending the output to an XWindow and I keep getting
> failures.
>
> I have the uvcvideo module loaded and /dev/video0 is present.
>
> I am running openembedded on the Gumstix Verdex Pro XL6P. Could it be that
> the camera is USB 2.0 and the Verdex Pro is only rated for USB 1.1?
>
> This is what I see when I plug the camera in...
>
> root@gumstix-custom-verdex:~# usb 1-2: new full speed USB device using
> pxa27x-ohci and address 4
> usb 1-2: configuration #1 chosen from 1 choice
> uvcvideo: Found UVC 1.00 device VF0560 Live! Cam Optia AF (041e:406d)
> input: VF0560 Live! Cam Optia AF as
> /devices/platform/pxa27x-ohci/usb1/1-2/1-2:1.0/input/input3
> 4:3:1: cannot get freq at ep 0x84
>
> When I try to gst-launch with the v4lsrc or v4l2src elements and I get the
> error below. I have tried a variety of settings using the 'video/x-raw-rgb'
> cap but I always get the same error. The videotestsrc element works fine
> with ximagesink.
>
> root@gumstix-custom-verdex:~# gst-launch v4l2src ! ximagesink
> Setting pipeline to PAUSED ...
> ERROR: Pipeline doesn't want to pause.
> ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Could not
> negotiate format
> Additional debug info:
> gstbasesrc.c(2584): gst_base_src_start ():
> /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
> Check your filtered caps, if any
> Setting pipeline to NULL ...
> Freeing pipeline ...
> root@gumstix-custom-verdex:~#
>

It looks like your camera does not produce anything that can be
displayed by ximagesink. Cameras usually output yuv data and some
produce jpeg (or otherwise) encoded data.

Wim

> Any help would be greatly appreciated...
> Thanks,
> John Buckley
>

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Stefan Sauer

Re: v4l2src0: Could not negotiate format

In reply to this post by John Buckley

John Buckley schrieb:

can you run v4l-info and post the output. Or look at the log of
GST_DEBUG=v4l2src:4. Or just try gst-launch v4l2src ! decodebin2 !
xvimagesink

Stefan

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John Buckley

Re: v4l2src0: Could not negotiate format

Stefan,
Thanks for the help. I was able to get things working by loading gst-plugin-jpeg. I did an opkg update and searched the /var/lib/opkg/gstreamer package listing for jpeg and found the package.
I guess I still don't quite understand how linux software modules and packages are put together. That will come with time, I hope.

Now, I need to speed up the camera throughput, figure out how to get rid of all the o/s overhead, and get my application to run as efficiently as possible.

John

----- Original Message -----
From: "Stefan Kost" <[hidden email]>
To: "Discussion of the development of GStreamer" <[hidden email]>
Sent: Tuesday, November 3, 2009 12:34:05 PM GMT -05:00 US/Canada Eastern
Subject: Re: [gst-devel] v4l2src0: Could not negotiate format

John Buckley schrieb:

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