Issue scheduling frames to BMD from gstreamer

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tpat36

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  • Real Name: Taylor Patton

Issue scheduling frames to BMD from gstreamer

PostTue Nov 12, 2019 7:55 pm

Hi,

We are having occasional issues with the BlackMagicIO driver for linux. We are using gstreamer's decklink plugin (version 1.16.1), desktopvideo version 10.8.5-a4, DeckLink Duo 2. The issue presents itself as follows:

* gstdecklinkvideosink.cpp (from gstreamer decklink plugin) will start logging "error: Failed to schedule frame: 0xffffffff80000008" repeatedly
* Immediatly after, BMD logs "BlackmagicIO: WARNING: Ran out of free frames."

During this issue the output video on the decklink starts lagging and audio sounds distorted. We've seen this issue happen in the middle of playback or at the beginning of playback. We are trying to get to the bottom of this issue of why the decklink plugin cannot schedule frames in time to the BMD driver. Is there any logging we can add to the BMD driver to help determine the root cause of this issue? If frames are being delivered too late to the BMD driver, could we get additional BMD logs for that scenario? Would there be any other reason that frames could not be scheduled successfully to BMD?

We have been working with the gstreamer community to improve scheduling frames which they have done for us. When this issue happens we are not seeing any late/dropped frames being logged from gstreamer. It's very difficult to reproduce this so we need to know exactly why the frames are failing to be scheduled to BMD before we can get a fix from gstreamer.

In case it helps, this is what the decklink output looks like in this scenario:

https://pulse.elevationchurch.org/link/ ... 0d1dff5de3
The issue starts around the 11 second mark and is ultimately resolved when we detect the error and reset the entire gstreamer pipeline.

OS: Centos 7
Kernel: 3.10.0-693.el7.x86_64
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Ian Morrish

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Re: Issue scheduling frames to BMD from gstreamer

PostTue Nov 12, 2019 11:07 pm

Presume you are not running a virtualization host on the same machine, Xen or KVM. These can cause problems (I have similar problem on Windows with HyperV host also running)
Regards,
Ian Morrish
Video Integrated Scripting Environment
(Windows PowerShell with ATEM driver + more)
https://ianmorrish.wordpress.com
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tpat36

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  • Real Name: Taylor Patton

Re: Issue scheduling frames to BMD from gstreamer

PostTue Nov 19, 2019 1:07 am

Not running a virtualization host, xen or kvm

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