iMovie macOS Legacy Video Formats

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iMovie macOS Legacy Video Formats

Anybody know what video formats are considered to be "legacy" by iMovie 10.1.13?

This version is a real pain. In its "forward looking" approach to "legacy" clips, it now takes five times longer to complete a project as iMovie now converts the "legacy" clips to some other format before they become useable.

Until this internal conversion is complete, the video stutters along and precision edits are impossible. To make it worse, Apple does not define what constitutes a "legacy" clip nor provides a Preferences option to NOT convert the clip, so until you're smack in the middle of things do you know that you're now trapped until the clips are converted.

Right now the CPU is screaming, fans maxed out, doing this conversion. This in no way "speeds things up" as the Welcome to iMovie screens proclaim.

Now, the video has to convert to the new format and then, when exporting, it has to render all over again. This is adding hours to the time it takes to complete a one hour video in iMovie.

Once more it seems Apple believes that everyone has unlimited budgets to swap out all their well functioning recorders, cameras and video kit to meet the new world order on their timeline. Bad play Apple.

Posted on Oct 13, 2019 2:28 PM

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Answer 1

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Reflective Turtle Author

Level 1

52 points

Oct 15, 2019 10:48 AM in response to Rich839

Confirmed this is a bug in 10.1.13. I re-ran the project using 10.1.12 and it ran smoothly, with no internal conversion or super high CPU loading or screaming fans. Report submitted to Apple.

To clarify, the original clip is an AVCHD package. Still a supported format with iMovie 10 on Mojave and Catalina.

On importing, iMovie retains the video in its original format but converts the audio stream to DVD LPCM (lpcm), stereo, 48 kHz, 32 bits/sample and puts it all inside a .mov container. This can be found in the iMovie Library package, digging down to the Original Clips folder. Note that this conversion seems to be normal behaviour by iMovie and is not the source of the problem.

Handbrake is a great tool. Use it all the time. For just doing audio conversions—leaving the original video intact—a super fast way is to install and use the ffmpeg command line tools from Terminal. https://www.ffmpeg.org

I've downgraded everything to 10.1.12 until Apple resolves this bug.

RT

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Answer 2

Oct 13, 2019 8:11 PM in response to Rich839

Hi Rich839

Thanks for the reply. Truly appreciated.

After taking a read through the article and the link it references, detects and converts incompatible media files, it seems as though this is probably a huge bug in 10.1.13. The clip in the iMovie project is on the supported compatibility list. For reference, the video stream is H264 - MPEG 4 AVC (part 10) (avc1), 1920 × 1080 at 29.97 FPS. The audio stream is DVD LPCM (lpcm), stereo, 48 kHz, 32 bits/sample.

In iMovie, running File > Check Media for Compatibility returns "No media compatibility issues were detected in the library...". The raw clip runs and scrubs smoothly in QuickTime Player Version 10.5 (935.5).

I may try to find a copy of 10.1.12 and run the project again.

RT

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Answer 3

Rich839

Level 8

47,250 points

Oct 13, 2019 11:04 PM in response to Reflective Turtle

You might try converting the clip outside of iMovie with a video converter like the free download, Handbrake, that you can get here:

https://handbrake.fr/

Sometimes the lpcm audio codec can be problematic. iMovie likes Mp4/AAC. Handbrake by default will convert to that.

— Rich

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Answer 4

Rich839

Level 8

47,250 points

Oct 15, 2019 11:24 AM in response to Reflective Turtle

For those who don't want to downgrade, what happened when you converted the .mts clips in the AVCHD package to Mp4/AAC with Handbrake?

I don't doubt your findings, but I have not heard of iMovie converting audio to LPCM. I had an incompatible legacy avi file in iMovie that was in LPCM audio format. When iMovie converted it the resulting audio format was AAC, not LPCM. My file was not initially an .mts file like in your case.

-- Rich

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Answer 5

Oct 15, 2019 1:07 PM in response to Rich839

Hi Rich:

Once I confirmed the bug was in 10.1.13 I didn't bother fusing about to work around it. Converting the individual .mts streams and then importing each of those—just too time consuming when it all works as it should (and has for literally years) in 10.1.12 and virtually every version of iMovie before that.

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Answer 6

Rich839

Level 8

47,250 points

Oct 13, 2019 5:28 PM in response to Reflective Turtle

Hi, Reflective Turtle,

This Apple bulletin lists the compatible formats and the legacy non-compatible formats:

https://support.apple.com/en-au/HT209029

-- Rich

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iMovie macOS Legacy Video Formats

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