What is this error "an unknown error occurred (-12911)"

I've got the same problem with some movies playing on ATV. On ATV I get "An error occurred loading this content. Try again later." When I play it on my Mac Mini in iTunes it plays fine but if I try to play it on the ATV from the Mac Mini using AirPlay, I get "An unknwon error occurred (-12911)'.

Mac Mini = Max OSX Mountain Lion

ATV = software version 6.0

A bit more information:

All of the videos that are producing this error worked before the ATV 6.0 update. All are HD. All contain video that is taller than 1,080 pixels.

I'm re-encoding one of them now to make it 1,080 pixel tall (or fewer).

I'm seeing the same error on my iPad running iOS7 for some files, the same files create the error on my aTV too.

These files played fine on the iPad under iOS6, found this post as that error has just cropped up after iOS7 upgrade - hadn't tried them on the aTV before.

For me it seems x264 encode with the tune "animation" trigger the error on my iPad mini, if I redo the same encode without any tune in x264 the file is playing fine with no error...

TitouDoc you are a genius - thanks so much for your post.

I forgot the rule of assumption and assumed my problems were OS upgrades.

I had infact tweaked x264 settings in HB. No obvious issues in iTunes but after reading your post I tested old settings to new.

My findings = iTunes is more permisive than iDevices (or aTV)

These are the tweaks I added to the front of the default settings I was using which slowed down HB and increased picture quality (slightly) BUT evidently broke iOS compatibility.

direct=auto:rc-lookahead=60

Can you guys explain more what you did to make this work? I took the same mkv file, encoded with Apple TV 3 preset and it did not airplay, encoded with iPad preset and it played fine, albeit with the lower quality video and stereo audio associated with that preset. I'm using Mavericks and Handbrake 0.9.8 x86_64. Any help is appreciated, I certainly want to be able to airplay the 1080p and DD 5.1 file if possible.

Im having the same issue...dont remember making any changes to the handbrake settings. Anyone figure out what in the ATV preset is causing it?

I've just fiddled around a bit and my standard transcode settings for HB in the GUI are High Profile, then an RF of 18, the H.264 Preset slider set to veryslow, detelecine to Default, and then all English audio tracks and subtitles. It takes a long time to transcode, but it looks fairly good on a TV (via a Mac mini). My iPads (2 and Air) won't play these, but it looks like backing off the Preset one notch to slower will play. So for the iPad, anyway, it's the change between the slower and veryslow settings. I can see what the changes in the parameters are, but haven't delved into what the different settings really mean yet, and probably still won't know what is going on after that.

Between Mavericks and iOS7 it's sure been a downhill Fall for Apple software.

It's something to do with the ref= count in the parameters. A veryslow x264 Preset slider value in the GUI (then checking the Use x264 Advanced Options Panel checkbutton and selecting the Advanced tab) sets the Reference Frames setting to 16. Backing that up to 8 while leaving everything else the same seems to make the files playable. I haven't tried values 15->9 to see if they work. The tooltip for Reference Frames says there may be hardware limitations on the upper value. So I guess I'll redo a lot of stuff with this new setting and the other stuff above.

ref=15 is OK. ref=16 is not. This could be a HB bug or a iOS bug or a hardware limit. HB pulldown menu shows 1-16 as possible values. Maybe they forgot to subtract 1 and the value in the file should be 0h -> Fh. Or maybe Apple forgot to add 1 and a value of 0 (coing from HB) is not valid. Or maybe everyone really knows what's going on and <16 is just a hardware limit.

Thanks for this great thread. For me, turning off the "animation" tune in Handbrake made the video playable on my iPhone 4.