# Black boxes flickering quickly across video feeds

**URL:** <https://discourse.lynckia.com/t/black-boxes-flickering-quickly-across-video-feeds/125>\
**Category:** Uncategorized\
**Created:** [September 1, 2016, 11:33pm UTC](https://discourse.lynckia.com/t/black-boxes-flickering-quickly-across-video-feeds/125 "2016-09-01T23:33:41Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Chad\_Phillips](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.lynckia.com/chad_phillips/32/27_2.png) [@Chad\_Phillips](https://discourse.lynckia.com/u/Chad_Phillips)\
**Post date:** [September 1, 2016, 11:33pm UTC](https://discourse.lynckia.com/t/black-boxes-flickering-quickly-across-video-feeds/125/1 "2016-09-01T23:33:41Z")

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I’ve been running into an odd display issue, hoping someone here has an  
idea what’s causing it.

Some of my users report black boxes flickering rapidly all over the video  
display area encompassing the individual feeds. The boxes are not  
constrained to the size of a single feed, so I doubt it’s a server side  
issue. See attached screenshot for reference, it was one of the flickers  
caught by a user.

I’m stumped as to what could be causing this. Some stupid thing I’m doing  
in my layout code? A bug in Chrome when a bunch of video elements are  
placed next to each other? Any other sane possibility welcome 🙂

[black-flicker-bug-screenshot.pdf](https://canada1.discourse-cdn.com/flex031/uploads/lynckia/original/1X/411c1d59e7d5ea4c39cb36baef3249ee1e6ba164.pdf) (373 KB)

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**Author:** ![Chad\_Phillips](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.lynckia.com/chad_phillips/32/27_2.png) [@Chad\_Phillips](https://discourse.lynckia.com/u/Chad_Phillips)\
**Post date:** [September 2, 2016, 10:40pm UTC](https://discourse.lynckia.com/t/black-boxes-flickering-quickly-across-video-feeds/125/2 "2016-09-02T22:40:08Z")

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I’ve adjusted my feeds to QVGA quality for more than 4 simultaneous  
connections, and that seems to have helped. Besides lowering the  
resolution, is there anything else I can do to impact the bit rate? I don’t  
think I’ve seen any other settings for that.

For those interested, the original issue I found posted was here:  
[https://groups.google.com/forum/#!topic/discuss-webrtc/lvXCygdSlbg](https://groups.google.com/forum/#!topic/discuss-webrtc/lvXCygdSlbg)

And a fair number of seemingly related bugs already filed:

[https://bugs.chromium.org/p/chromium/issues/detail?id=635283](https://bugs.chromium.org/p/chromium/issues/detail?id=635283)  
[https://bugs.chromium.org/p/chromium/issues/detail?id=632741](https://bugs.chromium.org/p/chromium/issues/detail?id=632741)  
[https://bugs.chromium.org/p/chromium/issues/detail?id=630394](https://bugs.chromium.org/p/chromium/issues/detail?id=630394)  
[https://bugs.chromium.org/p/chromium/issues/detail?id=565937](https://bugs.chromium.org/p/chromium/issues/detail?id=565937)

Brian, did you ever figure out a way to solve this issue for your use case?On Friday, September 2, 2016 at 1:27:32 AM UTC-7, Pedro Rodriguez wrote:

> ## I’m afraid that’s a Chrome WebRTC rendering issue that’s been present since around Chrome 49. What we know is that the more stressed the CPU (or maybe even the GPU) is, the more likely the problem is. With a big number of videos, Chrome can even freeze. Ways to lighten the processing load is using lower bitrate videos or using SlideShowMode.
> 
> Pedro Rodriguez
> 
> On 02 Sep 2016, at 01:33, Chad Phillips \<[thehunm...@gmail.com](mailto:thehunm...@gmail.com) \<javascript:\>\> wrote:
> 
> I’ve been running into an odd display issue, hoping someone here has an  
> idea what’s causing it.
> 
> Some of my users report black boxes flickering rapidly all over the video  
> display area encompassing the individual feeds. The boxes are not  
> constrained to the size of a single feed, so I doubt it’s a server side  
> issue. See attached screenshot for reference, it was one of the flickers  
> caught by a user.
> 
> I’m stumped as to what could be causing this. Some stupid thing I’m doing  
> in my layout code? A bug in Chrome when a bunch of video elements are  
> placed next to each other? Any other sane possibility welcome 🙂
> 
> –  
> You received this message because you are subscribed to the Google Groups  
> “lynckia” group.  
> To unsubscribe from this group and stop receiving emails from it, send an  
> email to [lynckia+u...@googlegroups.com](mailto:lynckia+u...@googlegroups.com) \<javascript:\>.  
> For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout).  
> \<black-flicker-bug-screenshot.pdf\>

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<div class="post-metadata">

**Author:** ![Pedro\_Rodriguez](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.lynckia.com/pedro_rodriguez/32/23_2.png) [@Pedro\_Rodriguez](https://discourse.lynckia.com/u/Pedro_Rodriguez)\
**Post date:** [September 2, 2016, 8:27am UTC](https://discourse.lynckia.com/t/black-boxes-flickering-quickly-across-video-feeds/125/3 "2016-09-02T08:27:28Z")

</div>

I’m afraid that’s a Chrome WebRTC rendering issue that’s been present since around Chrome 49. What we know is that the more stressed the CPU (or maybe even the GPU) is, the more likely the problem is. With a big number of videos, Chrome can even freeze.  
Ways to lighten the processing load is using lower bitrate videos or using SlideShowMode.–  
Pedro Rodriguez

> On 02 Sep 2016, at 01:33, Chad Phillips [thehunmonkgroup@gmail.com](mailto:thehunmonkgroup@gmail.com) wrote:
> 
> I’ve been running into an odd display issue, hoping someone here has an idea what’s causing it.
> 
> Some of my users report black boxes flickering rapidly all over the video display area encompassing the individual feeds. The boxes are not constrained to the size of a single feed, so I doubt it’s a server side issue. See attached screenshot for reference, it was one of the flickers caught by a user.
> 
> I’m stumped as to what could be causing this. Some stupid thing I’m doing in my layout code? A bug in Chrome when a bunch of video elements are placed next to each other? Any other sane possibility welcome 🙂
> 
> –  
> You received this message because you are subscribed to the Google Groups “lynckia” group.  
> To unsubscribe from this group and stop receiving emails from it, send an email to [lynckia+unsubscribe@googlegroups.com](mailto:lynckia+unsubscribe@googlegroups.com) [mailto:lynckia+unsubscribe@googlegroups.com](mailto:lynckia+unsubscribe@googlegroups.com).  
> For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout) [https://groups.google.com/d/optout](https://groups.google.com/d/optout).  
> \<black-flicker-bug-screenshot.pdf\>