White noise in some concert video recordings??

[globalist]

So my wife just returned from a pop concert and she wanted to play back the videos she made at said event with her iPhone SE. Turns out most of the recordings, while having the video intact, also have white noise in place of the actual audio. One video has the first 2 seconds of actual audio and then it too cuts to white noise for the rest of the duration.

The only sensible explanation I can come up with is that the concert organizers employed some sort of technology that jams the audio at random points of the show. Is this a thing? Or is there some known issue with the SE microphone? Maybe the music was too loud in those parts? But why would this introduce uniform white noise throughout the whole video?

I just used her phone to record a random video in my room and the sound was picked up correctly. WTF is going on?

Thanks for any input!

 

[sarpler]

The only sensible explanation I can come up with is that the concert organizers employed some sort of technology that jams the audio at random points of the show.

.....that's a "sensible" explanation?

Is this a thing?

No.

Either her mic is dying and cuts out randomly (hardware issue), or the system is screwed up (software issue). First off, do a bunch of tests recording movies of different lengths in different noise environments to see if there's any pattern, or at least see how easy it is to reproduce. Then do a backup, DFU restore with a clean copy of iOS but DON'T log in with Apple or restore from the backup. Use the phone in a clean virgin state with no settings or apps or names or anything. Do the same recording tests and see if the problem is still there. If it is then it's a hardware failure. If it's not there, restore the backup and see if the problem comes back. If it does come back then the phone had some file that got corrupted. You'll have to do another DFU restore but this time copy all your photos and stuff over manually and set up all the apps as new (it'll be a pain in the butt, but currently there's no way to edit iphone backups to remove specific settings/system files so it's your only option).

 

[Camarillo Brillo]

The sound pressure levels are probably too high for the microphone and it is clipping badly would be my guess

 

[globalist]

The sound pressure levels are probably too high for the microphone and it is clipping badly would be my guess

I don't think it was the sound levels. First off, when clippng, why would it introduce white noise, exactly? Second, there were videos of the band playing really loud (Can't Buy Me Love cover level loud) where this issue is not present at all.

Looks like there is an issue with the iPhone mic in some instances:

https://discussions.apple.com/thread/7839954

 

[Analog Kid]

.....that's a "sensible" explanation?

It’s not completely outlandish:
https://www.dailymail.co.uk/science...top-people-taking-pictures-videos-stages.html

I can’t find a reference to anyone blocking audio though...

 

[sarpler]

It’s not completely outlandish:

That stuff is conceptual, it doesn't really work anywhere near well enough to be practical in real life for a whole variety of technical reasons. And anyway, most cameras these days have permanent IR filters and nearly all mics are tuned to filter out subsonic and ultrasonic sounds because there's no point capturing stuff humans can't see/hear. And using some kind of dynamic filter to allow concert venues to do broadcast DRM causes way too many false positives for everything else.

Whatever the problem is here, it's clearly internal to the phone itself.

 

[Analog Kid]

That stuff is conceptual, it doesn't really work anywhere near well enough to be practical in real life for a whole variety of technical reasons. And anyway, most cameras these days have permanent IR filters and nearly all mics are tuned to filter out subsonic and ultrasonic sounds because there's no point capturing stuff humans can't see/hear. And using some kind of dynamic filter to allow concert venues to do broadcast DRM causes way too many false positives for everything else.

Whatever the problem is here, it's clearly internal to the phone itself.

Yeah, I agree it’s almost certainly not intentional, but if the problem only manifested when bootlegging concerts I can understand why someone might wonder if there was some sort of countermeasure employed.