<html> <head> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body> Hello I have a Java application that implement a pipeline like following : gst-launch-1.0 v4l2src io-mode=2 device=/dev/video0 ! appsink max-buffers=1 drop=true with "emit-signals=true" and callbacks set. I stop with pipeline by sending an EOS message to the pipeline to stop and consume all buffers, wait EOS on bus and set pipeline to NULL All works fine for the first start but if I stop and restart immediatly the pipeline with another device, an error "device or resource busy" can be detected for the second start or later I have found several posts on Internet with the same problem : - bug of the driver ? No because I have the same problem with USB camera or capture card BT878 I have activated log in Gstreamer and detected that when v4l2bufferpool is stopping, only buffers in pool are released : for the 4 MMAP buffers allocated, only 3 are released on stop I have tested 3 versions of GStreamer : - Gstreamer 1.16 and 1.18 : KO - Gstreamer 1.10 : OK The problem seems to be in AppSink : - before GStreamer 1.16, a new Sample was allocated for each <code>gst_app_sink_try_pull_sample</code> : when the user "unref" the sample -> the buffer is "unref" and returned in pool - after version 1.1??, the sample is recycled : the buffer is "unref" only on the next <code>gst_app_sink_try_pull_sample</code> when <code>gst_sample_set_buffer is invoked or on </code><code><code>gst_app_sink_dispose </code></code>which is too late On stop, when v4l2src change state from PAUSED to READY , the device is closed but a buffer is still referenced by the last sample Is this correct ? Thanks for your help Christophe </body> </html>