[gst-devel] v4lsrc: Could not synchronize on resource

Kristofor Amundson kta719 at mail.usask.ca
Fri Feb 12 21:55:45 CET 2010

Hi all,

I'm working on capturing media from a VGA signal grabber using gstreamer. It
is a v4l device, so I am successfully able to capture using v4lsrc. I am
having an issue with unplugging the VGA signal though, because the signal
grabber does not send blank frames, so the gstreamer pipeline stops because
it cannot synchronize on resource. Are there any options for me to somehow
keep the pipeline running and just insert blank frames?

I am using GStreamer 0.10.25 and this is what the debugging output for the
v4lsrc plugin looks like during the failure:

0:00:12.858767651 15192       0xfa1f10 DEBUG                    v4l
v4l_calls.c:386:gst_v4l_get_chan_norm:<v4lsrc0> getting current channel and
0:00:12.860111669 15192       0xfa1f10 LOG                      v4l
v4lsrc_calls.c:690:gst_v4lsrc_buffer_finalize:<v4lsrc0> freeing buffer
0xe10e70 for frame 1
0:00:12.860159234 15192       0xfa1f10 LOG                      v4l
v4lsrc_calls.c:694:gst_v4lsrc_buffer_finalize:<v4lsrc0> requeueing frame 1
0:00:12.860169350 15192       0xfa1f10 LOG                      v4l
v4lsrc_calls.c:336:gst_v4lsrc_requeue_frame:<v4lsrc0> requeueing frame 1
0:00:12.998765970 15192       0xfa1f10 LOG                      v4l
v4lsrc_calls.c:265:gst_v4lsrc_grab_frame:<v4lsrc0> grabbing frame
0:00:12.998815357 15192       0xfa1f10 LOG                      v4l
v4lsrc_calls.c:84:gst_v4lsrc_queue_frame:<v4lsrc0> queueing frame 1
0:00:12.998829158 15192       0xfa1f10 LOG                      v4l
v4lsrc_calls.c:114:gst_v4lsrc_sync_frame:<v4lsrc0> VIOIOCSYNC on frame 0
0:00:13.294936018 15192       0xfa1f10 WARN                     v4l
v4lsrc_calls.c:124:gst_v4lsrc_sync_frame:<v4lsrc0> error: system error: No
message of desired type
ERROR: from element /GstPipeline:pipeline0/GstV4lSrc:v4lsrc0: Could not
synchronize on resource.
Additional debug info:
v4lsrc_calls.c(124): gst_v4lsrc_sync_frame ():
system error: No message of desired type
Execution ended after 12234652245 ns.
Setting pipeline to PAUSED ...
Setting pipeline to READY ...


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