# Video Flickering



## mfmcgreal (Jul 16, 2010)

Good afternoon,

I've recently noticed - in the past few weeks - an issue when viewing videos. They flicker/flash at certain points really fast, as if there's a glitch or bug with either the video, or my graphics card. This only occurs now and then, and only once or twice during a video, however it's catching my attention more and more .. 

The issue occurs consistently with the following video: https://vimeo.com/71901747

During certain points, a pink flash/flicker will occur .. Nothing that effects the video playing, but as if there is a software/hardware glitch somewhere. I've playedback the video in both Chrome and Safari, and Quicktime via my desktop, and same issue occurs. Please watch for yourself - it may just be an issue with the video file itself. 

That said, the problem has been occurring with other videos, particularly in Vimeo, which I browse rather frequently. 

Thanks,

Martin


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## mfmcgreal (Jul 16, 2010)

BUMP!


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## MartyF81 (Jan 23, 2013)

What kind of machine do you have? Processor, etc...

What resolution is that video playing att?

Usually at video bug like that is a product of a CPU or GPU having a problem processing/transcoding the video.

It could be a CPU or GPU failing... depending on how old the machine is. Especially since it happening in browsers, AND in quick time (which eliminates it being a streaming problem)

Have you tried the Apple Hardware test?


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## mfmcgreal (Jul 16, 2010)

MartyF81 said:


> What kind of machine do you have? Processor, etc...
> 
> What resolution is that video playing att?
> 
> ...


1) iMac (27-inch, Late 2013), 3.4 GHz Intel Core i5, 32 GB 1600 MHz DDR3, NVIDIA GeForce GTX 775M 2048 MB

2) 1920x1080p - though it's occurring in lower resolutions too - It appears to occur more when I full-screen videos.

To be fair, it's only the video I linked which is glitching in Quicktime too. Other videos appear to working fine .. Except iTunes, which is failing to playback 1080p movies .. (though I'm convinced this is a streaming issue w/ my internet)

As far Apple Hardware test, I haven't no .. Is this in any way dangerous? I have to deliver two pieces of content to clients in the next three or four days, so understandably I'm reluctant to put my machine through its paces with tests etc. until I've delivered the content .. 

Cheers


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## mfmcgreal (Jul 16, 2010)

UPDATE: Just ran Apple Hardware Tests .. No errors found ..


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## MartyF81 (Jan 23, 2013)

Well, if it is only this video.... then its probably something in the encoding of that video file that is choking the processor when it is transcoding it. Even more likely since it is on a video made with Magic Lantern (which is a hack and not officially supported).

AHT isn't really dangerous no.. and it doesn't like stress test the machine. but honestly in any situation.. if you have critical work it is always best to do that first. You never know if your issue is that some piece of hardware is failing... and even going on Facebook could be the straw that breaks the Camels back.

I would do this:

1. Finish your project.
2. Back up everything with Time Machine to an external drive.
3. Back up important files manually to an External drive, just to be safe.
4. Run AHT.

If problems found in AHT... probably need to take to Apple.

If no problems found by AHT... I would probably wipe the machine and do a clean OS install. Then try the video. If the issue is there on basically what would be a "clean" computer... then you likely have a hardware problem that AHT isn't finding.

If after a clean install... the problem disappears.. then you had some software that was causing the problem.

Since you made a Time Machine backup in step 2... you can always restore from the TM back up to restore your Machine back to how it was before you started all this..


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## mfmcgreal (Jul 16, 2010)

MartyF81 said:


> Well, if it is only this video.... then its probably something in the encoding of that video file that is choking the processor when it is transcoding it. Even more likely since it is on a video made with Magic Lantern (which is a hack and not officially supported).


Is there any glitching/flashing occurring for yourself when playing the video I linked? 

Magic Lantern is surely irrelevant since once the video has reached Vimeo, it's by that point just a 1080p H264 file for example? I've watched dozens and dozens of ML videos in the past week too, and nothing like this has occurred.

It's only that video which the glitching occurs consistently without fail .. Other videos are fine .. The glitch or flash, which as I say, is a millisecond long, is only occurring now and then in videos, usually about 2secs into a video, especially when in full-screen mode. The bug is very subtle, to the point where once its happened, I'm doubting whether its just my eyes, or it did indeed occur .. Its definitely there though, I've noticed it too many times in the past few weeks for it be human error ..


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## MartyF81 (Jan 23, 2013)

Ya actually I did just play the video... and see a bunch of glitching all over the place.


H264 is just a codec. But Garbage in = Garbage out. If the original file is bugged during creating... its not going to be fixed by simply playing it somewhere else.

For example... if I misspell a word in a document and save it as .doc its going to still be misspelled in Word, Google Docs, Text Edit, etc... What I open the file in... doesn't fix the original problem.


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## mfmcgreal (Jul 16, 2010)

MartyF81 said:


> Ya actually I did just play the video... and see a bunch of glitching all over the place.
> 
> 
> H264 is just a codec. But Garbage in = Garbage out. If the original file is bugged during creating... its not going to be fixed by simply playing it somewhere else.
> ...


I misunderstood your original point .. 

I thought you were speaking as if Magic Lantern was still actively creating the issue whilst streaming, which of course isn't possible. As you say, if the problems in the original file, it will be there forever, regardless of codec.


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