GNOME Bugzilla – Bug 734264
ksvideosrc gives GStreamer-CRITICAL **: write map requested on non-writable buffer continuously
Last modified: 2015-02-03 23:17:45 UTC
Created attachment 282501 [details] Backtrace of all threads When launching the command: gst-launch-1.0.exe ksvideosrc ! d3dvideosink The camera is very slow and it outputs GStreamer-CRITICAL **: write map requested on non-writable buffer.
Also happens on GStreamer 1.5.0 (from git, Zeranoe build 2014.08.05, x86). Camera speed, however, looks normal. Camera is webcam "HP Webcam 101". Other than warning in "gst_buffer_map_range", there isn't much else relevant. Attaching debugging output on levels 3-7; level 7 and higher stops at "gst_ks_video_src_create" with something along the line "Acces code invalid" (translation of "Koda za dostop ni veljavna"). Debug outputs at https://drive.google.com/file/d/0B709JEu7P-brNFNvSVJuNkc0WEk
The internal buffer pool handling (not using GstBufferPool but its own) looks a bit weird, I would expect the bug to be there.
commit bd5e9a544229f6d1e0ee58dde1e24a2f7301f57e Author: Nicolas Dufresne <nicolas.dufresne@collabora.com> Date: Tue Feb 3 17:44:34 2015 -0500 ksvideosrc: Fix buffer handling The pseudo buffer pool code was using gst_buffer_is_writable() alone to try and figure-out if cached buffer could be reused. It needs to check for memory writability too. Also check map result and fix map flags. https://bugzilla.gnome.org/show_bug.cgi?id=734264