No audio in Quicktime movies

Waht kind of movies are they? MOV, AVI, ...?

Have you an Add-On like Perian installed so that you can play other types of movies?

That's really strange.

You can try to play the videos again and again and when the audio stops you can take a look in the Activity Monitor to see whats taking the CPU power...

EDIT:

You can for example take an AVI movie and save it with quicktime to a MOV (not export). But it's still not a real MOV after saving. I unfortunately can't realy explaine that, but in this way it's not a full MOV and working on an other way than a normal one.

There are many issues about Lion at the moment. A lot of them have to do with CPU usage. So next time you have this problem go to activity monitor and try to quit all programs and only quicktime stay tuned. Than have a look in the activity montor and be sure that the cpu is not in 100% or more usage.

If the sound still is stuck after this you can post that here. If not, one of the closed programs could be the reason.

EDIT:

If you want to change a movie to MOV, you have to export it. As i told, save as isn't a complete change.

I'm having the same problem. Under the previous version of Quicktime I used Save As to convert movies from wmv format to mov and they played fine in that version of Quicktime. With the current version only a few seconds play. I can jump to different areas in the movie and I will get a second of sound and then nothing.

I'm not getting any unsual CPU activity.

If your movie is not to large, try to export it. Maybe it's all about the "real" MOV...

I tried exporting and I get an error that the file is corrupt. So something changed in the Quicktime version between 10.6 and 10.7. It seems very strange that a movie saved under the old version does not play under the new version. Luckily the movies I saved under the old Quicktime version are not a big deal to lose but if they were I would be pretty upset with Apple.

If you open the Movie in QT and you press Command + I you can see unter "format" whitch is the real format independent on the extention.

Maybe it's not QT. If the format is Xvid for example it could be the perian or flip4mac thats need an update...

I'm bumping this because it's another thread about the same issue that hasn't been resolved. Doesn't anyone out there know how to fix it? More to the point, why hasn't Apple provided a fix after all this time - it's been six months since some of these threads were started!

On an asied, it's my first time using Lion and it is the slowest, buggiest Mac OS I've used since the original OSX and OS10.1.

I'm having the same problem, not only with the quicktime application itself, but also with the quicktime videos on apple.com movie trailers and product videos for iphone ect. (which are also .mov format), I get sound but no video on chrome and safari, they used to work when i first got my macbook pro 2 years ago

I've tried re-installing both browsers, quicktime and perian, and the problem still persists.

any luck with a solution yet?

I did a complete erase and re-install of my mac the other day after backing up my music n stuff, first time since i bought my mac two years ago so was probably due for some good maintenance anyway lol

re-downloaded perian flip 4 mac and chrome and the videos now work fine in both chrome and safari can only guess that the files for the relevant codec were probably corrupt

if you are going to use this solution then don't forget to back-up any files you dont want to lose!(music, photos, videos ect.)

Hi mate, already done a complete reinstall - this is a new Air so shouldn't have needed a clean install in the first place - but still didn't fix it. Have been having a lot of problems with Lion lately, including complete OS freeze, Launch Pad reshuffling itself at random, dodgy cursor/trackpad, and generic icons showing up instead of the proper ones. I'm thinking of taking this machine back and swapping it for another one. If the same problems persist with Lion, I'll be selling this one and going back to a late-2010 model Air with Snow Leopard. Already got a 2010 model 13.3" Air that hasn't given me any problems, but this new 11.6" Air has been nothing but trouble. Not sure if it's the new model or Lion OS, but not happy.

I have been having this problem as well and stumbled upona fix today it seems. For me, the newest version of Quicktime was not playing audio but QT7 played fine for some reason. Today I was playing with the Perian preferences and switched the default Audio Output selection from Dolby Pro Logic to stereo (on the built in speakers I don't notice a difference) and subsequently every video file I've tried has played audio. This fix might be specific to my issue but it takes only a few seconrds to try so why not.

It's NOT an APPLE OS problem!

It has to be a Quicktime problem!

I'm running Snow Leopard with 2GB of RAM and all I'm trying to do is play a simple 30 second to 3 minute audio file in an OnLine Red Cross Training class. I rebooted and they all played in one class then the next class they only play for 2 secs and stopped. I ran the disc permissions in Tech Tools Pro 6 with no effect. I rebooted again with no effect. I tried it in Google Chromium and Safari. All my software is up to date and I am not running anything else but the browser. I'll be Most happy to supply someone with a Video taken with my iPhone of what is happening if it will do any good.