Intermittent very low fps(sometimes zero) with few specific h264 and h265 RTSP input streams sources when used with gst-v4l2 based gstreamer-1.0(version gst-1.14.5) decode pipeline

[kunal das]

Few specific h264 and h265 RTSP input streams sources when used with nvidia specific gst-v4l2 based gstreamer-1.0 (version gst-1.14 and ubuntu-18.04) decode pipeline intermittently yields very low fps (in the range of [~0/1 fps]).

Issue seems caused by the gst_video_decoder_drain_out function erroneously getting called inside gst_video_decoder_chain_forward function.

Required changes to fix the issue seems available with gst-1.16 and to resolve the issue need to backport the relevant OSS fixes from gst-1.16 to gst-1.14 on ubuntu-18.04.

The mentioned issue was reported on with: https://bugzilla.gnome.org/show_bug.cgi?id=796771

Corresponding fix was incorporated with below:
https://github.com/GStreamer/gst-plugins-base/commit/62cb08404b9bd055c45cc1d5b71141e927ad748a

We need to backport above fix on top of gst-1.14.5 on ubuntu-18.04 in order to have out-of-box fix available with default gstreamer-1.0 version 1.14 on ubuntu-18.04

[Loïc Minier (lool)]

Hi Kunal,

thanks for your report; I looked at the upstream bug, and I didn't find a reproducer to confirm the bug and its resolution with the patch; would you have one?

This might be a candidate for a SRU update; the process is outlined in https://wiki.ubuntu.com/StableReleaseUpdates and is largely about assessing risk of regressions.

[Loïc Minier (lool)]

The mentioned upstream patch was included in the 1.15.2 release and jammy and focal are unaffected; bionic does not have this patch in 1.14.5-0ubuntu1~18.04.3

[kunal das (kudas)]

Hi Loïc Minier (lool), thanks for the quick reply.

We have reproduce steps using nvidia gst-v4l2 decoder plugin pipeline on gstreamer-1.0 (version gst-1.14 and ubuntu-18.04)
We can provide reproducing pipeline on nvidia platforms for the same if needed.

We are looking forward to get this fix backported to default gstreamer-1.0 (version gst-1.14 on bionic ubuntu-18.04)

Please let us know the feasibility of mentioned request.

[Loïc Minier (lool)]

Please attach the reproducing pipeline; it's a bit tricky to organise access to Jetson hardware to the right people, so if you had a reproducer that we could run without Jetson hardware, that would be best!