Videos played on my new mac have audio stutter, online or offline.
January 14, 2017 3:24 PM   Subscribe

My nearly-brand-new, fully loaded iMac has a problem playing videos. The audio skips, as if tiny pieces of it have been taken out, or as if someone is sporadically unplugging the speakers for a fraction of a second. This happens even if the video is on my hard drive, and I'm playing it offline.

At first, I thought this must be a buffering issue. So I tried letting the streaming video load for a while before I played it. Didn't matter. Then I tried playing from various different sources: YouTube, Amazon, Netfilx. Didn't matter. I tried switching browsers, but that made no difference. On this computer, I almost exclusively use Chrome; the only reason I have even opened Safari was for this purpose.

I tried it with a VPN, and that also had no effect.

Eventually, I downloaded one of the files I was trying to watch (as an mp4). Playing it directly from my hard drive, using VLC, I had the exact same issue. So now I'm flummoxed. Perhaps it's a problem with the video card, or the driver, etc.

I have done a lot of googling around about this. It's certainly a subject of discussion on many forums, and has been for about a decade. Almost always, the discussion peters off, or ends with an argument, as the person helping insists it's an issue with the cache or buffering, and the supplicant insists that it isn't.

This is a very new iMac. I'm pretty savvy about what I install, and I don't think I have installed any malware, especially in the two weeks I've owned the computer.

Retina 4K, 21.5-inch, late 2015
3.3 GHz Intel Core i7
16 GB 1867 MHz DDR3
Intel Iris Pro Graphics 6200 1536 MB
posted by bingo to Computers & Internet (6 answers total) 2 users marked this as a favorite
Mr Arnicae asks: Do you have a fusion drive? If so they frequently have these issues. Also check to make sure your software is fully updated?
posted by arnicae at 3:35 PM on January 14, 2017

I'm curious if it's some issue with the audio hardware/software. If you use headphones (headphone jack) instead of speakers, does the problem persist? Additionally, if you have a USB headset or something that bypasses the normal audio processing altogether, try that too. These might help narrow it down.

Also might be worth opening Activity Monitor and seeing if there's a weird resource issue when playing audio (crazy CPU/RAM spikes and so forth).

This is really strange. I've never experienced it on this iMac (late 2013). The above comment makes an interesting point. I've never used Fusion drives so maybe there is an issue with those that may influence this.
posted by kup0 at 3:36 PM on January 14, 2017 [2 favorites]

This is a very new iMac. I'm pretty savvy about what I install, and I don't think I have installed any malware, especially in the two weeks I've owned the computer.

Have you run all the available system updates? Many iMacs are still shipping with OS X 10.12.1, and if you have that you should upgrade to 10.12.2; I found .1 to be buggier than expected, and .2 includes updates to audio and CoreMedia.
posted by bcwinters at 4:05 PM on January 14, 2017

A classic "how could I have been so stupid" situation.

It was the headphones. I only use this computer with bluetooth headphones, so I didn't even think about them as a separate issue.

Interestingly, there was a point during which this issue did not happen on this computer with these headphones. So either the headphones are breaking, or something changed on the computer that they don't like.

Anyway, I plugged in some earbuds with a physical line in, and the problem goes away.

Too bad, I liked those bluetooth headphones. I'm charging them now, in the hope that it was a power issue... they don't have firmware to update that I know of. (66 Audio BTS)
posted by bingo at 4:31 PM on January 14, 2017 [4 favorites]

Bluetooth audio is always a problem, especially for latency and bandwidth. I'd never use it if a hardwired option was available.
posted by spitbull at 6:45 PM on January 14, 2017 [2 favorites]

Epilogue: After charging the bluetooth headset, the problem went away, even with the headset. So it was just a symptom of the headset battery running down, I guess. Seems obvious in retrospect, but I would have figured there would be different symptoms: the sound would gradually fade out, or just stop working. But I guess not.
posted by bingo at 7:38 PM on January 15, 2017

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