Cannot play .MOV with QuickTime

However, there are about a half dozen .MOV files that simply won't open. The message I receive is "The document “filename.MOV” could not be opened. The decoder required for this media cannot be found."

The MOV extension refers to the file container type— MOV being the generic QT file container. For a file o be open/playback back compatible, the file must contain data that is supported by the player being used. This means that your system must be configured with the required audio and/or video codec needed for plyaback and you must be using a QT player that can access the codec.

I took a look at other video files I brought over from my PC and there are quite a few .MOV files that are playing just fine. Any ideas why some .MOV videos are playing just fine while others aren't? And more importantly, what do I need to do in order to get these videos to play?

Try using the QT "Inspector" or the Finder "Info" window to determine what codecs were used to create the compressed data contained in the MOV file and install compatible codec components if available and/or the older "legacy" compatible QT player if required.

I'm using Mac OS X, Version 10.7.4 and QT, Version 10.1.

Without knowing the particular codecs involved, no specific advice/instructions can be provided.

Jon, thank you for this detailed reply. I hope I can ask you a couple of follow up questions. I have Mac OS X 10.6.8. I am unable to play high def video clips that are stored in iPhoto '11 with QT10. They play very choppy (but are fine when I view in iMovie or on the camera itself). I see this was a common problem when Snow Leopard came out. Is there a fix for this?

I have installed QT7 based on earlier suggestions in the forums, but how do I tell iPhoto to use QT7 and not QT10 when playing video clips? I can tell it to use QT7 on a per use basis but would like to tell it to use this going forward.

Here is the codec on one clip that is choppy: H.264, Linear PCM, in case this helps.

Thanks in advance for any suggestions.

KR

I am unable to play high def video clips that are stored in iPhoto '11 with QT10. They play very choppy (but are fine when I view in iMovie or on the camera itself). I see this was a common problem when Snow Leopard came out. Is there a fix for this?

There could be a number of issues at work here ranging from the particular H.264 Profile and Level combination used to record the video to the specific data rate used to various storage problems. I would normaly prefer to examine a sample file before passing judgement since the file could contain anything from a common Main Profile Level 3.1 video at 2.5-10 Mbps to a High Profile Level 5.0 or greater video at 160 Mbps or more nor have you indicated what you mean by hi def here which could commonly be anything from 720p24 to 1080p60. As to iMovie playback, I believe this app only uses one field for realtime display during editing which cuts the processing of displayed data in half. As to fixes, I normally convert my content to 720p24 H.264/AAC for iTunes management and greater playback compatibility with all of my "mobile" (i.e., iPhones, iPads, TVs, etc.) devices and archive the original content for video editing purposes.

I have installed QT7 based on earlier suggestions in the forums, but how do I tell iPhoto to use QT7 and not QT10 when playing video clips? I can tell it to use QT7 on a per use basis but would like to tell it to use this going forward.

Normally you can't without either copying the source file for easy access or by accessing the "library" file directly and either telling the Finder to open it in QT 7 or by drop-opening it in the QT 7 app. (Once again, I do not use iPhoto as a general video management tool.)

Here is the codec on one clip that is choppy: H.264, Linear PCM, in case this helps.

The H.264 codec is highly scalable which is probably why Apple uses it as their default codec of choice. It can be used with video data rates ranging from 64 Kbps to 300,000 Kbps. Based on the use of Linear PCM audio, this would appear to be a file targeted for video editing rather than general playback and may have used target settings that force the dropping of frames during normal playback. Without knowing more about the source video compression format and how it was encapsulated in the MOV file, it is difficult to say if you playback is typical or atypical on your particular platform with or without other processes running simultaneously. Basically, QT is programmed to drop frames if it cannot keep up with playback. How many frames are dropped will depend on how far decoding lags behind display processing. This can range from a random skips to severe, lengthy freezes of the content. As previously noted, iMovie 11 would normally display every other field and your camera/camcoder may well include hardware accelleration to reduce its work load.

Jon, thank you for this thorough, detailed reply! I'm not sure I understand a lot of it, it's a bit beyond me, but I'll try to break it down when I get back to this issue. Thank you for taking the time to answer thoroughly...

Oh, I also meant to say that I never had a problem playing back/viewing hi-def movie clips, taken with my digital camera, in iPhoto (via QT) until I installed iLife '11 and upgraded to Snow Leopard. I didn't do any converting, it just worked. Thanks.

Oh, I also meant to say that I never had a problem playing back/viewing hi-def movie clips, taken with my digital camera, in iPhoto (via QT) until I installed iLife '11 and upgraded to Snow Leopard. I didn't do any converting, it just worked.

Which problem? You say that some files won't play and that others play but are choppy. This sounds like two different problems.

For instance, if a file opens and plays in QT 7 but not in the QT X player, then it is more likely that the files contain codecs that are "legacy" (old) and are no longer supported. Basically, the QT X player is not an update of QT 7. Instead, the is a totally new re-write of QT which tragets the playback of modern compressions formats. In some cases, third-party codecs can no longer be accessed by QT X and in others Apple simply dropped support for codec components which were formally/are still supported by QT 7 routines exclussively. In a similar manner, "choppy" playback could be the result of high definition routines that must switch back and forth between 64- and 32-bit QT processes in combination with excessively high data/frame rates and/or latest "security" upgrades which frequently interfer with QT file playback. In addition, you indicated you have upgraded to Lion OS v10.7.4 which appears to have some bugs in it based on the number of complaints/issues reported in this forum. (I.e., I elected not to upgrade as soon as these ussues began to surface.)

Unfortunately, without a sample file to examine/test on my system, all I can do is speculate as to possible causes of your problems.