Pixelated iTunes video playback — but only on newer MacBook Pro

[kuwisdelu]

I'm confused and getting frustrated here.

So I got one of the new base model 15" MacBook Pro's today, and everything has been mostly great, except some issues I've been having with video playback iTunes.

Before this, I was on a 2007 C2D MacBook, and iTunes performed like a champ on it (despite the obvious hardware difference).

However, I've been having problems with video playback on the same version of iTunes (10.2.1) on my new MacBook Pro that I didn't have on the MacBook.

Namely, scenes on the videos I play in iTunes on the new MBP get incredibly pixelated/blocky once in a while so movies become unwatchable. The same scenes play completely fine on the older MacBook in iTunes.

The movies play identically in Quicktime X Player (there's some pixelation there, too, but at least it's the same between the two, and I chalk it up to the immaturity of its libraries vs. QT 7.) And both play perfectly in MPlayer on both machines. But iTunes behaves completely differently when playing them back.

What is iTunes doing differently between these two computers? They're both on 10.2.1. The movies are all H.264 high profile w/ AAC audio in an mp4. Also the subtitle positioning is a bit wonky in iTunes on the new MBP where it's fine on the older MacBook.

Does anyone have any ideas? Anyone else having similar video problems with iTunes?


ETA: Ahh, after an hour or two of trying to figure this out, I decide to post, and then five minutes after I post, I finally solve it. I just tried re-muxing the video and audio streams from the old mp4 into a new mp4 with Subler on the new MBP and it plays fine, now. No idea exactly why that worked since the same file plays fine on iTunes on the MB and plays identically in all other players, but whatever... It's going to be a pain if I have to remux all my TV shows again, too...

ETA2: Urghh. Nevermind, this only seems to work for some of the movies. For others it still leaves messed up playback.

 

[kuwisdelu]

I installed Quicktime 7 from the optional installs and the movies play fine in Quicktime 7 Player, too. So what could iTunes be doing differently from both QT 7 and QT X that it's only doing on my new MBP but not my old MB?

 

[bob69]

Finally someone with the similar issue to mine!

Right,

I've been having a similar issue...

I use subler to mux the h264 and AAC and AC3 streams into a .m4v file.

I have been doing this for over a year, and the results have been excellent - play perfectly on iPad (1st gen) ATV (2nd gen) MacBook (original unibody) and iMac (late 2009).

However recently I have found that certain files are getting a "grey mist" type pixelation at the start, or finding that certain scenes later on are pixelated...

Now in my case I have routed out the cause (although this doesn't mean I can actually fix the issue)

in subler:

1. video [box ticked]
2. aac audio [box ticked]
3. ac3 audio [box unticked]

This has been my order for every movie in my collection... and has worked for ages. Now it seems that certain ones don't!! (others work just fine though)

Now I have played the files in QTX, iTunes and QT7. the issues are present in iTunes, and QT X! But NOT QT7.

So I'm thinking that this has to be an iTunes issue (QTX being updated with it I assume...) as QT7 hasn't had an update..

Now I use perian to play the dolby track (ac3) and this has worked with iTunes, QTX, and QT7. However, since my iTunes update, I can see the dolby track in the iTunes audio selection tab, however I can't selected whereas I used to be able to..

Now, I have found that this solution may fix your issue, open subler, select new, drag and drop the old .mp4 file in put both the video track and the aac track into it, then drag and drop the same file in again, and this time only insert the aac track. - you should have 1 video and 2 aac audio, make sure both tick boxes are checked, and save the new file.

I found that this solved my issue when both audio sources were checked at the same time and saved.

I haven't tested this on anything other than; iTunes, QTX, and iPad. This may throw up issues on the Apple TV (1 or 2).

Now I don't actually know the exact root cause and the following may be to blame:

iTunes - has been updated recently
QTX - has been updated recently
Perian - hasn't been updated recently
Subler - has been updated recently (0.14)

My incline is to believe that there may be something a miss within subler since the iTunes update, or that Apple have locked something off (not able to play dolby tracks in iTunes anymore)..

Let me know if you find anything, have any thoughts.

Hope this kinda helps..

EDIT

Having pissed about endlessly with everything, the only conclusion I can come to is that it's a "perfect storm scenario" where every program is to blame for this.. It'll be something small and probably insignificant that Apple did to iTunes... or that subler has included in the code, or that perian overlooked and hasn't updated yet.. Hopefully whatever it is, it will get fixed.

The two audio solution may be a good stop gap (hope it works for you) I have to try it on the ATV2 to see if the audio the amp picks up is the dolby track and not the aac...

EDIT 2

After more testing and playing around, I'm convinced that they updated something in iTunes, and that subler is gonna need an update to account for the change in iTunes.

If you films/tv shows have a dolby track the solution is simply to open the file in subler, uncheck the tickbox for aac track, and check the one for the dolby track - save it, and itunes should still play the aac (stereo) track by default (based on my testing.. - but I do have perian installed).
If you don't have an ac3 track, then I really don't know how to fix the issue, I honestly believe though that it's just a slight change in subler that'll be needed, so before remuxing entire libraries, wait for the next update...

 

[one09jason]

I have the same problem. Early 2011 MBP, blocking, pixelation, and other artifacts when playing through iTunes (full-screeen mode). I've discovered something interesting about this problem. If I open the video in question from the finder into QuickTime Player X first and leave it open, then go back to iTunes, it plays fine from iTunes. It also plays fine in QuickTime Player X and QuickTIme Player 7.

Can anyone replicate this?