Duplicate/missing frames in IMovie '11 ver. 9.0.4

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Level 1

10 points

Duplicate/missing frames in IMovie '11 ver. 9.0.4

Hi,

When I import Canon 7D HD .MOV files (H.264 MP4, 1920x1280, 29.97 fps) into IMovie '11, I noticed that some frames are duplicated (probably to make up for missing frames), which results in motion "judder" when playing the clip in the main project window. This is especially noticeable when panning a shot, and appears to happen at every 3.5 sec of video.

It does not matter if video optimization (large or original) is turned on or off, when importing the clip. (I usually use original) Audio track remains unaffected.

Inevitably, this judder/stuttering is passed on to any form of video export, be it MP4 ,DV, MOV, etc., which ruins final product.

What's really strange is that the optimized clip that's created by IMovie and stored in the events folder, plays smoothly in Quicktime, no missing or duplicated frames. So it is something in IMovie's UI that's creating this problem. This should not happen at all - what is shown in IMovie's playback window should match the original or optimized video, frame for frame.

Is there anything I am missing as far as settings, or is something not right on my system? And yes, I did send Apple a bug report.

I am doing this work on a late 2007 17" 2.67 GHZ Intel Core Duo Macbook Pro, 4GB ram, Mac OS X 10.6.8 (slow, but steady)

Thanks for your input.

MacBook Pro (17-inch 2.4 GHz), Mac OS X (10.6.8)

Posted on Jan 11, 2012 8:21 PM

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Answer 1

Jan 25, 2012 4:46 AM in response to Dave Glagola

Hi! I ran into same problem!

I have iMovie version 11 9.0.4 (1634). Running on OSX Lion, 13" Macbook Pro Mid 2010 C2D 2.4GHz.

I used Samsung Galaxy S II to capture a small video of GT5 replay from LCD tv in 1080p (PAL, 25Hz) mpeg4 format. No matter what export settings I use the exported video file from iMovie has a several duplicate frames. I took the video file into Avidemux and stepped it through from frame to frame. Duplicate frames are:

26,27

42,43

104,105

120,121

137,138

153,154

and so on.... that is the reason for judder/jerky movement. Other programs like Blender (or Openshot movie editor on Linux) produced a nice and smooth video.

So I looked more into this problem and I noticed that when importing a video file into iMovie, DO NOT use the "optimize video" option. If I import my short movie into iMovie without doing the optimizing part, editing seems to be a bit slower but the exported video file plays smoothly. I couldn't find any duplicate frames. After using the "optimize full original size" option and then re-exporting the movie it was full of duplicate frames again...

I'm not sure what the optimizing does (using a faster intermediate codec/format?) but for this simple test it certainly ruins exported movies...

Not sure if this is any help to you, but you might want to try it...

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Answer 2

Dave Glagola Author

Level 1

10 points

Jan 25, 2012 8:40 PM in response to Henry Palmroos

I'm tempted to say that the skipped frames are intentional, but I won't go there. 😉

Anyway, one work-around that I came up with is exporting the Canon clips out of MPEG Streamclip using the Apple Intermediate Codec, 30 fps, default size (1080x1920), then import that into IMovie with optimization turned off. This seems to smooth things out on the final render & export.

But, for some reason the color saturation and brightness take a hit when using Streamclip. Something in IMovie's optimization (it uses the Apple codec) make the clips look good, meaning they match the originals, despite the missing frames.

The only reason why I was using optimization is that the Canon clips are H.264 MP4's, and they do not play well in IMovie when imported with it turned off. Also, there's the possibility of exporting a MP4 clip as an edited MP4 may introduce frame problems (compound compression?).

Well hopefully, Apple will sort things out, but probably not until the next major revision. (2015?....)

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Answer 3

Mar 16, 2012 10:23 PM in response to Henry Palmroos

Thanks. Turning off optimisation worked for me.

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Answer 4

Dave Glagola Author

Level 1

10 points

Mar 17, 2012 8:43 PM in response to unklebacon

You're welcome. If you do use the MPEG Streamclip work-around that I've described above, try using IMovie's color adjustments to bring the color back closer to the original clip. The following seems to work well for me:

Exposure 100%

Brightness 12%

Contrast 0

Saturation 134%

Red Gain 102%

Green Gain 98%

Blue Gain 102%

Note that this will add time to rendering, and you can apply these settings globally to several selected clips all at once. (Hint: apply the settings to all your clips in the events window, before assembling your movie) Have fun!

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