Quicktime on Mavericks outputs stuttering audio.

I think you are not correct. On Mountain Lion Quictime version is 10.2 (10.3 in Mavericks) and i can see from the activity monitor that is also 64bit. Those .mov files that at least i speak about (animation codec - quicktime) will play in Mountain Lion without problem. In Mavericks this is not happening. There is no possibility for preview and when you open with quicktime it will convert it to pro res 444 Quicktime. Problem is somewhere else, for now i do not care much as i only installed Mavericks for testing and i go back to Mountain Lion. When this fixed and 2D DOCK! i'll come back.

For those who are having the stuttering problem in Quicktime Player/Youtube I may have a solution. It seems like the ever so clever (sarcasm) App Nap feature may be to blame. I entered the following commands to disable it on Safari and Quicktime Player and the problem appears to have disappeared.

In the Terminal, issue the following commands

defaults write "com.apple.Quicktime Player" NSAppSleepDisabled -bool YES

defaults write "com.apple.Safari" NSAppSleepDisabled -bool YES

For the time being, touch wood, the problem has vanished. Would be interested to know whether this works for anyone else just in case something coincidental happened.

I just performed these terminal commands and tried out an mp4 video on my machine. Still crackling

I did this with iTunes and it worked, my last post I forgot to say to restart iTunes though..

Didn't see a way to disable app nap with QuickTime, wasn't thinking terminal though. When I get home I'll try this with QuickTime.

@dave try restarting QuickTime and see if that helps. iTunes still crackled playback until I restarted.

restarting quicktime didn't make a difference

Sorry to hear that, was hoping to solve the problems for folks cause it is a really annoying one. You do have to restart whatever is being used in order to pick up the changes to the defaults but I can see you have tried that.

If I re-enable app nap for Safari the problem returns in Youtube ( although not as bad maybe, not sure ), and disabling it again it goes away. So it is definitely having an effect there. With Quicktime player I can't get it to break again. Obviously those actions do something to affect the sound but not quite sure in what way.

I start also experience crackle sounds in youtube videos.

Do you guys have problems in standard videos in youtube or it comes random?

For me it is standard , i can stop the crackle by open audio midi setup (from utilities) and play with the 44khz-48khz output

Ok here's a further update from me. I have an MP4 file of a TV show and it plays with crackly sound via QuickTime 10.3 on my mid 2010 iMac but plays fine via QuickTime 10.3 on my 2013 MacBook Air 11 inch, both have recent Mavericks installs as updates. Perian installed on both.

No I'm even more puzzled....

Gary

CRACKED IT! for me anyway!

I use a Focusrite Saffire Pro 14 FireWire audio interface with my iMac and just the inbuilt sound on my MacBook Air....all audio crackes go away when I switch my iMac sound preferences to intermal speakers.

The problem is the Saffifre Pro 14 audio interface, looks like new drivers are required for Mavericks

Something is definitely going on with playback. I went to the apple store today to see if the macbook airs were exhibiting same symptons on video files (black bar at the top moving up and down, color whacking out) and they did the same thing. Its really noticeable on the Jony Ive ipad air video. Submit bug reports !!!

I had problems with all Youtube videos. I can't seem to get them not to have problems now. Problem seems gone. Perhaps those App Nap changes did something, perhaps something else. Whatever it was it seems to be permanent now. Very odd.

I use a Macbook Pro running sound through a Focusrite PRO DSP 24 and it, as above, is working fine. Didn't have any problems with any other sound source, just audio in Quicktime Player/Plugin.

I'm also using a FireWire audio interface whe I experience the audio crackling. Using internal speakers has no issues at all but using my FA-66 in quicktime produces the effect. no problems with the FA-66 outside of quicktime though

To me it is clear that bug reports must made. If they don't fix these issues soon, I will seriously consider reinstalling Leopard. It is not for users to find multiple and complex workarounds for such issues. Rather, the new OS should just work fine -or in fact better than the previous one, since that is why changes are introduced in the first place!

Ya-haaa.. Unsupported hardware.. Yup. Here we go! Nice catch Gary!

I'll have to add this to my list.

Stuttering happens only when I go "Fullscreen" with both QuickTime & iTunes.

(note: I posted the iTunes stuttering problem on the iTunes forum.)