Appsink: does not respect allocation query being serialized

Submitted by Dimitrios Katsaros

Link to original bug (#797016)

Description

Created attachment 373433
Demo of how allocation query handing is not being respected

The allocation query is serialized, which means that it should respect the flow of data and follow after all buffers that have come before it. However, appsink does not respect this. I have added a demo showing how this behavior breaks v4l2src functionality. I have also added a simple patch for fixing the issue, by calling the same code that GST_QUERY_DRAIN runs.

Attachment 373433, "Demo of how allocation query handing is not being respected":
main.c