The Mac, AVCHD and 24p

The only workable solution I have found for editing 24p video from my Canon HG10 (AVCHD) on Mac OS X is to:

1. Use iMovie 9 to import and transcode the AVCHD video to Quicktime AIC video files. Keep in mind that 24p on the Canon and some other cameras is actually stuffed into the 60i interlaced video stream. So you can import into iMovie even though iMovie does not know what to do with the 24p frames. (NoteĀ  – I only have Final Cut Pro 5 which does not support AVCHD. The newer versions, 6 and 7, do support AVCHD directly, although as best I can tell, they do not support the 24p stuffed into 60i video streams directly. So you still have to do the next step.)

2. Use the free JES Deinterlacer’s inverse telecine feature to remove the 2:3:3:2 pulldown from the previously converted AIC file. Just look in your Movies Events folder and let JES Deinterlacer process the imported movie clips. Let JES transcode the input back out to AIC files.

3. At this point, you now have 24p AIC files. You’ll need to run Final Cut Pro to do a good job of editing 24p because Final Cut Express doesn’t do 24 fps timelines. In FCP, set your timeline compression sequene to use the AIC compressor – that way you don’t have to render the AIC files to some other format. Drag your inverse telecined 24p files into Final Cut and have fun editing.

Timewise, this process is actually pretty fast. AIC files do “explode” to about 3 to 5 times larger though, than their original AVCHD format. The newer versions of Final Cut support ProRes422, which is a more compact compressor with excellent quality. But if you don’t yet have FCP 6 or 7, that option is not available.

So why go through this trouble to edit 24p? For me, I like progressive images much more than interlaced. However, 24p enables shooting at 1/24th or 1/48th shutter speeds, making it ideal for low light situations.

Update: VoltaicHD’s problems, noted in the next paragraph, have since been fixed. More here – VoltaicHD now works fine on the HG-10 and presumably more cameras too.

Update: Cineform Neo Scene, for both Windows and Mac, appears to do AVCHD conversion and 24p pulldown removal for 24p embedded in 60i streams. Costs $129.

Other options? I’ve tried VoltaicHD, whcih is recommended by many for transcoding AVCHD files to AIC on the Mac (both Intel and PPC versions). VoltaicHD includes a 24p feature that is supposed to remove the pulldown. But based on my testing with the Canon HG10, it only works some of the time. Some clips are successully processed while others have no pulldown removal. I’ve done many experiments with the settings and have concluded that VoltaicHD probably only works on pulldown removal on the 3 specific cameras they list on their website, even though the underlying data formats should be identical. Thus, don’t buy VoltaicHD for the 24p feature unless your camera is specifically listed.

3 thoughts on “The Mac, AVCHD and 24p”

  1. Edward,

    Thanks for this post. This was helpful to me, as I’m finally getting around to using FCP 6 with my Canon HG10 footage. I’ve been using iMovie, which has become quite a nice product, but didn’t support 24p.

    Today I tried the VoltaicHD converter, and it seemed to work well. Seeing my footage at 24p instead of 60i or 30p was eye-opening. Definitely more cinematic. Voltaic now lists several cameras as supported. I think the VHD product was $40.

    But I like the idea of using software I already own, and staying with one vendor, if possible, so I will try out your iMovie-JES-FCP solution, and see how that works.

    Thanks again for taking time to share with your fellow filmmakers, Edward!

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