How to delay Mac sound output?

August 21, 2009 6:53 AM

I want to delay the sound output from my Mac Mini so I can get it to sync with video from a different source.

I've got a radio commentary (available via Safari or iTunes on the MacMini) that is up to a minute ahead of the TV feed I'm watching on my laptop. I want to watch the TV feed with the radio commentary roughly in sync.

Is there a software solution out there that will allow me to adjustably delay the entire audio out from the MacMini?

Even better would be the ability to delay the audio from a particular application & I'd like the option to be able to sync both feeds on a single Mac.

posted by i_cola to computers & internet (6 comments total)

Also, simplicity breeds content :-)

(The feeds in question are Test Match Special audio & Sky Sports' video if you hadn't already guessed.)
posted by i_cola at 6:55 AM on August 21

Okay, here's a last-resort hack solution if nobody comes up with a cleaner one. You'll need a copy of Audio Hijack Pro, which is $32.

Set up AHP so that it's 'hijacking' the audio from the app you want to listen to (in this case, Safari or iTunes), and muting it, and recording it to an MP3 on disc. Then, one minute later, you open up that MP3 in VLC, and start playing. VLC will keep reading in data from the MP3 for as long as AHP keeps dumping data to the disk.

It'll take a bit of thinking to adjust the delay once you've started it, but it is possible, by adjusting the playhead in VLC.

Here's a screenshot of me listening to Spotify with a 30 second delay.
posted by chrismear at 7:33 AM on August 21 [2 favorites has favorites]

Why don't you start the commentary up and just pause it for a specified period of time? Don't stop it, just pause it. Is that possible?
posted by proj at 7:55 AM on August 21

Good idea Chris. That's a start...I have AHP. I'm going to time the audio delay (easy with cricket although not so easy when we're skittling the Aussies like today!) and then time the start up based on that. I'll experiment with playhead/pause too.
posted by i_cola at 8:50 AM on August 21

I've never tried it with an audio stream only, but VLC has an audio delay option that you can adjust in the audio preferences or on the fly (I believe the default hotkeys are f and g). I normally use this to synchronize audio with video in the same file, but it seems plausible that you could use it to just delay an audio stream even if there's no video attached.
posted by shammack at 8:51 AM on August 21

Well Chris's idea with proj's mod works well. I timed the delay first & then tweaked using pause. I think I'll email the Rogue Amoeba folks and see if they fancy having a pop at this. They have a video/audio sync facility in Airfoil (QuickTime only tho'. My feed is via Evil Silverlite) so this would be a nice extra.
posted by i_cola at 9:35 AM on August 21