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Step frame/slow motion look when I convert 720 29.97 to 23.98?
I made a sequence in MC 5 that I exported from Sorrenson 6 as a QT 480p (16:9) using the Avid DNxHD 145 codec @ 30fps. What I need is an Apple ProRes 422 (HQ) QT @ 23.98fps.
I was told to open up a final cut 23.98 final cut project and sequence, import my QT and select “no” when asked if i wanted to use the settings of the imported material this was, i’m guessing, it would keep the settings within the project. i exported the sequence using the apple pro res 422 (HQ) and after the export finished and i played down the sequence, there were a few spots that looked to have “step frame” problems or, for lack of a better word, certain clips looked to be in slow motion/stuttery.
Does anyone have any idea what we are doing wrong? Any info is greatly appreciated. Thanks.
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1 Reply
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[Joseph Donarummo] “I was told to open up a final cut 23.98 final cut project and sequence…”
Whoever told you that headed you down a path to frustration. Here are a few things to consider:
– when going from 30p to 24p, most conversions simply throw away frames
– Final Cut Pro is one of the worst offenders in dealing with off-frame media
What I recommend is if you really need to go to 24p, use Compressor. Compressor has a feature known as Optical Flow which can smooth out these frames as best as it can to make it appear as though no information has been lost. It is still losing temporal information no matter how you slice it, but with Optical Flow in Compressor you can get a far better result than with Final Cut.
Open Compressor and drop in your 30p clip.
Find the preset named “Apple ProRes 422 (HQ)” and drag and drop it onto your clip.
Click on the preset name as it is attached now to your clip.
Now you will notice that the Inspector will allow you to adjust the settings. In the Encoder tab, change the video settings so that the frame rate is exactly 23.976.
In the Frame Controls tab, click the gear icon and turn Frame Controls ON.
Set Resize to Fast, Output Fields to Same as Source, Deinterlace to Fast. This sets all of these to be ignored since we aren’t doing any of these. However we are going to “retime” the clip.
Set the Retiming controls to Best. This invokes Optical Flow and will interpolate the frames you have down to 23.976fps, keeping as much of the temporal information intact as possible. Leave duration set to 100% of source, as you want to keep the duration intact.
Click submit and wait a while. You will be left with a 24p file that is possibly the best looking clip you can get with software.Keep in mind this might still not be good enough. The better alternative would be to pass your clip through a realtime hardware frame rate converter like a Teranex VC-1. You will get better results from that. My advice above assumes that you don’t have access to that ~$30K piece of gear. Good luck.
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