gstreamer 1.20.0 breaks video on Linux

[kflak]

Hi,

I just updated my system, and it seems gstreamer breaks any video playback. Getting this when running the videoPlayer example:

[notice ] ofGstUtils: Got context from element 'vaapipostproc0': gst.gl.GLDisplay=context, gst.gl.GLDisplay=(GstGLDisplay)"\(GstGLDisplayX11\)\ gldisplayx11-0";

[notice ] ofGstUtils: Got context from element 'vaapipostproc0': gst.vaapi.Display=context, gst.vaapi.Display=(GstVaapiDisplay)"\(GstVaapiDisplayGLX\)\ vaapidisplayglx0", gst.vaapi.Display.GObject=(GstObject)"\(GstVaapiDisplayGLX\)\ vaapidisplayglx0";


(videoPlayerExample:12633): GStreamer-Base-CRITICAL **: 16:43:43.970: basetransform: second attempt to fixate caps returned invalid (NULL) caps on pad vaapipostproc0:sink

(videoPlayerExample:12633): GStreamer-Base-CRITICAL **: 16:43:43.970: basetransform: second attempt to fixate caps returned invalid (NULL) caps on pad vaapipostproc0:sink

(videoPlayerExample:12633): GStreamer-Base-CRITICAL **: 16:43:43.971: basetransform: second attempt to fixate caps returned invalid (NULL) caps on pad vaapipostproc0:sink

(videoPlayerExample:12633): GStreamer-Base-CRITICAL **: 16:43:43.971: basetransform: second attempt to fixate caps returned invalid (NULL) caps on pad vaapipostproc0:sink

(videoPlayerExample:12633): GStreamer-Base-CRITICAL **: 16:43:43.971: basetransform: second attempt to fixate caps returned invalid (NULL) caps on pad vaapipostproc0:sink

(videoPlayerExample:12633): GStreamer-Base-CRITICAL **: 16:43:43.971: basetransform: second attempt to fixate caps returned invalid (NULL) caps on pad vaapipostproc0:sink

(videoPlayerExample:12633): GStreamer-Base-CRITICAL **: 16:43:43.972: basetransform: second attempt to fixate caps returned invalid (NULL) caps on pad vaapipostproc0:sink
[ error ] ofGstUtils: startPipeline(): unable to pause pipeline after 5s[ error ]
ofGstUtils: gstHandleMessage(): embedded video playback halted for plugin, module qtdemux0  reported: Internal data stream error.[warning] ofGstVideoUtils: update(): ofGstVideoUtils not loaded

Needless to say, this is a HUGE bug. Please, please, please wait with upgrading gstreamer until this is fixed.

Running this on Arch Linux, oF version 0.11.2. Tested on xorg (bspwm) and wayland (sway).

EDIT: tested now with the latest nightly build, of_v20220210_linux64gcc6_nightly, and getting the same result.

[kflak]

Additional information: My computer runs an AMD iGPU and an NVIDIA eGPU. My second computer, which only has an intel iGPU, shows the same behavior: works perfectly fine before upgrade, no joy after.

[kflak]

I downgraded now to 1.18, and all is well. Of course, this is not good still, as it effectively locks my computer to a specific point in time, excluding any updates until this works. I am very inexperienced with c++ in general, but if somebody could point me in the right direction I might take a stab at working on a fix?

[kflak]

Starting to look into this a bit more now... How can I set the path to the gstreamer binary that oF looks for? I am thinking of keeping a separate build of gstreamer 0.18 on my system, so that I can use this for my oF projects. Processing has released a new version of the video library that bundles the old version, and this works on my system.

[StaffanMelin]

I can confirm this problem.

It works on Debian 11 Stable with GStreamer 1.18
but not on Debian 11 Testing with GStreamer 1.20.

I get the following error in case 2:

[notice ] ofGstVideoGrabber: initGrabber(): selected device: SHUNCCM2MP: SHUNCCM2MP
[notice ] ofGstVideoGrabber: initGrabber(): selected format: 640x480 video/x-raw YUY2 framerate: 30/1
[notice ] ofGstUtils: setPipelineWithSink(): gstreamer pipeline: v4l2src name=video_source device=/dev/video0 ! video/x-raw,format=YUY2,width=640,height=480,framerate=30/1  ! videoconvert   ! appsink name=ofappsink enable-last-sample=0 caps="video/x-raw, format=RGB, width=640, height=480"
Segmentation fault

I will try to get more information on the error.

[kflak]

Thanks for confirming! I was starting to wonder if I am the only one with a 1.20 problem :-) For what it's worth, I wrote a guide on how to revert to 1.18 on Arch Linux. Not exactly recommended practices, though... https://roosnaflak.com/tech-and-research/restoring-gstreamer-to-1-18-on-arch-linux/

[StaffanMelin]

Thank you for the link @kflak! I will check it out.

I tried to debug the issue, using the videoGrabberExample program.

ofApp.cpp:
vidGrabber.initGrabber(camWidth, camHeight);

which calls

bool ofGstVideoUtils::setPipeline(string pipeline, ofPixelFormat pixelFormat, bool isStream, int w, int h)

(in ofGstutils.c line1076)

This function seems to work, but when it returns (line 1164)

my program seg faults.

[kflak]

Unfortunately I am not able to do a debug anymore, since I am back on 1.18, however I never got a segfault. In my case the plugin was simply disabled, and I got a gray screen instead of video. The program kept running, which makes me a bit suspicious if we are dealing with the same bug...?

[StaffanMelin]

Good question, @kflak!

In the OF forums there is a similar report (to mine, with the seg fault):
https://forum.openframeworks.cc/t/segmentation-fault-on-examples-computer-vision-opencvexample/39508

[StaffanMelin]

Last try: I am now on GStreamer 1.20.1, and using the OF nightly build from 4th of April. Still a seg fault, unfortunately. Going forwards with debugging and fixing is beyond my abilities. But I will gladly help making more tests, providing info etc! :)

[dimitre]

Not sure if it is related but I've seen an issue on GStreamer itself posted here
https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1083
And it seems some videos, not all trigger the segfault. Maybe this is related to the difficulty to reproduce in different systems.

[StaffanMelin]

Thanks, @dimitre, this could be related. I see the person with the bug was running 1.18.5 of GStreamer, I have 1.18.3/4 on my Debian 11 Stable (which works).

@kflak, exactly which version did you revert to?

[kflak]

I reverted to the newest possible version of 1.18, which is 1.18.5.

[kflak]

Not sure if it is related but I've seen an issue on GStreamer itself posted here https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1083 And it seems some videos, not all trigger the segfault. Maybe this is related to the difficulty to reproduce in different systems.

A bit silly of me not to raise an issue on gstreamer immediately, but I wasn't sure if this was just an idiosyncratic quirk of my system or not. I will soon install arch on a new computer, and will take the opportunity to test 1.20 then on a fresh install.

PS: the work on your website looks great, @dimitre!

[StaffanMelin]

I don't really know how to move further with this. I get a seg fault even when trying to do video capture...