Seeking with kmssink does not work

moritz.vieli moritz.vieli at
Sun Dec 22 11:24:25 UTC 2019

Ok, best to try latest as usual.
--> I know. Unfortunately, I am still unable to build Gstreamer on the
Raspberry from the sources (but I am still a Linux noob ;)).

I'm convinced there is something that could be improved there, assuming you
are ready to spend the time.
--> As long as I can help, sure!

You should maybe share
a little more info about what you are doing.
--> I am developing a system to play audio, video, MIDI and lighting shows
in sync. Gstreamer is used as the backend. Everything worked fine on the
Raspberry Pi 3 and I am trying to port it to the Raspberry Pi 4 now. I had
to switch from glimagesink to kmssink, because of a problem with the colors
that's why I first suspected kmssink to be responsible for the seeking
issues. However, it turns out, it really seems to be an issue with
v4l2h264dec. I just tested it with avdec_h264 and it worked fine. However,
this decoder is too slow on the Raspberry and everything stutters. This is
the current pipeline for video files:
uridecodebin ! queue ! kmssink

Also, you should check
your kernel logs too, as there is a good deal of work done by the
--> There are indeed errors, as soon as I seek:
Dec 22 11:02:35 xxx kernel: bcm2835-codec bcm2835-codec:
bcm2835_codec_stop_streaming: Timeout waiting for buffers to be returned - 5
Dec 22 11:02:35 xxx kernel: bcm2835_mmal_vchiq: buffer_from_host:
msg_context not allocated, buf 7147fe8b
(2nd message repeated 7 times)

Additionally, I found another error thrown from my app:
(unknown:1570): GStreamer-CRITICAL **: 10:29:30.813:
gst_buffer_resize_range: assertion 'bufmax >= bufoffs + offset + size'

Please let me know, if you need any further information and thanks a lot for
your support!

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