[gst-devel] Crash in v4l2src when device is busy

[Stefan Kost]

On 27.08.2010 10:24, 4ernov wrote:
> Hello,
>
> I've faced some strange behavior of v4l2src when capture device is
> busy and I try to set it to READY state. The program crashes in some
> of GStreamer routines with the following error message:
>
> ERROR!  Error:  Device '/dev/video0' cannot capture at 640x480
> DEBUG   Error:  gstv4l2object.c(1920): gst_v4l2_object_set_format ():
> /GstPipeline:camera/GstV4l2Src:v4l2src0:
> Call to S_FMT failed for YUYV @ 640x480: Device or resource busy
>   

please file a bug with the backtrace and standalone test app attached.

thanks
Stefan

> Backtrace is like this:
>
> #1  0x02581e1e in gst_v4l2src_create (src=0x8353000, buf=0xb50fd1cc)
> at gstv4l2src.c:914
> #2  0x025c3765 in gst_push_src_create (bsrc=0x8353000,
> offset=18446744073709551615, length=4096, ret=0xb50fd1cc) at
> gstpushsrc.c:117
> #3  0x025b0881 in gst_base_src_get_range (src=<value optimised out>,
> offset=18446744073709551615, length=4096, buf=0xb50fd1cc) at
> gstbasesrc.c:2081
> #4  0x025b3327 in gst_base_src_loop (pad=0x8354010) at gstbasesrc.c:2334
> #5  0x0024ed6b in gst_task_func (task=0x83bd0c0) at gsttask.c:238
> #6  0x00250377 in default_func (tdata=0x809b7c0, pool=0x8076810) at
> gsttaskpool.c:70
>
> My code is just plain as in tutorial I think:
>
>     GstElement *v4l2src, *deinterlace, *videoscale, *tee,
> *ffmpegcolorspace, *queue, *xvideoscale, *ximagesink;
>
>     GstBus* bus;
>
>     GstCaps* caps = gst_caps_new_simple ("video/x-raw-yuv", "width",
> G_TYPE_INT, 400,
>                                                             "height",
> G_TYPE_INT, 300, NULL);
>
>     /* Create gstreamer elements */
>
>     _pipeline      = gst_pipeline_new("camera");
>
>     v4l2src      = gst_element_factory_make("v4l2src",  NULL);
>
>     deinterlace = gst_element_factory_make("deinterlace",  NULL);
>
>     videoscale  = gst_element_factory_make("videoscale",  NULL);
>
>     tee      = gst_element_factory_make("tee",  NULL);
>
>     queue   = gst_element_factory_make("queue", NULL);
>
>     xvideoscale = gst_element_factory_make("videoscale",  NULL);
>
>     ffmpegcolorspace = gst_element_factory_make("ffmpegcolorspace",  NULL);
>
>     ximagesink   = gst_element_factory_make("ximagesink", NULL);
>
>     if (!_pipeline || !v4l2src || !videoscale || !tee || !queue ||
> !ffmpegcolorspace || !xvideoscale || !ximagesink)
>     {
>             qDebug()<<"Elements could not be created. Exiting.";
>     }
>
>     gst_bin_add_many (GST_BIN (_pipeline), v4l2src, deinterlace,
> videoscale, tee, queue, ffmpegcolorspace, xvideoscale, ximagesink,
> NULL);
>
>     gst_element_link_many(v4l2src, deinterlace, videoscale, NULL);
>
>     gst_element_link_filtered(videoscale, tee, caps);
>
>     gst_caps_unref(caps);
>
>
>     gst_element_link_many(tee, queue, ffmpegcolorspace, xvideoscale,
> ximagesink, NULL);
>
>
>     g_object_set(G_OBJECT (ximagesink), "force-aspect-ratio", true, NULL);
>
>     g_object_set(G_OBJECT (deinterlace), "mode", 0, NULL);
>
>     if (_winid)
>     {
>         gst_x_overlay_set_xwindow_id ((GstXOverlay*)ximagesink, _winid);
>     }
>
>     bus = gst_pipeline_get_bus (GST_PIPELINE (_pipeline));
>     gst_bus_add_watch (bus, bus_call, this);
>     gst_object_unref (bus);
>
>     /* Set the pipeline to "playing" state*/
> //    gst_element_set_state (_pipeline, GST_STATE_READY);
>
>     /* Iterate */
>     g_print ("Running...\n");
>
>     g_object_set(G_OBJECT (_v4l2src), "device", str.c_str(), NULL);
>
>     gst_element_set_state (_pipeline, GST_STATE_READY);
>
> Is it a bug and so I should post it or perhaps I did something unsafe?
>
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