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Pixel aspect ratio
I’ve been trying to find a way to convert a 24 frame, 1080p clip to a 30 frame, NTSC clip. I’ve tried more combinations of Compressor than I can count, and I’m really close except for one thing: pixel aspect ratio.
The native HD clip has square pixels, and when I convert to SD the aspect ratio changes to NTSC-CCIR 601. This squishes my clip horizontally. That aside, the quality of the conversion was good (not blurry or anything), just squished. I need to leave my FCP sequence set to the NTSC-CCIR 601 aspect ratio, since my work is destined for cable TV.
I feel like I’m really close, but can’t make this last piece of the puzzle fit. I’ve asked for help on this before, but never brought up the issue of the pixel aspect ratio before. Any ideas? Thanks,
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7 Replies
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[Paul Campbell] “This squishes my clip horizontally.”
Paul,
Where are you seeing your squished NTSC movie in QT?
Qt by default display pixels as square therefor you see things distorted.
Import your NTSC movie to FC and check Anamorphic in the Browser.
Double click it and look how it looks in FC Viewer.
Rafael -
Hi, Rafa. This was happening in FCP, while trying to convert an HD/1080p clip w/ square pixels to an SD clip with NTSC pixels. I was using Compressor to do the conversion, and the only way I could get it to not be blurry was to convert it to NTSC. It was clean, but squished.
The good news is that I finally found a good workflow for converting the HD to SD so that it still looks sweet. (I won’t bore you with the details unless you’re interested 🙂 Thanks for getting back to me on this, and for all of your other replies while I was trying to figure this out. I guess I’ll be back soon enough to hound you about something else!!!
Cheers,
Paul
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[Paul Campbell] ” I finally found a good workflow for converting the HD to SD so that it still looks sweet. (I won’t bore you with the details unless you’re interested 🙂 “
I’m all ears for any interesting tip. So when you have time you explain me.
Cheers,
Rafa -
The mistake I was making was trying to get Compressor to do ALL the work (not only the frame rate change, but also the resizing). So, my workflow goes like this:
-Import the HD clip into a 720×480 timeline, with NTSC CCIR 601 pixel aspect ratio, no field dominance at 23.98 frames.
-Rescale the clip to 50 so that it fills the entire frame (some stuff will be clipped to the left and right, but the important stuff is within action safe)
-Render
-Set in/out points, and export to Compressor
-In Compressor, use the ProRes 422 preset. In video settings, change the frame rate to 29.97. That’s the only thing to change in Compressor.
-Run the job, and there you go. No blur, no weird interlace issues, no square pixel-to-NTSC pixel squishing.This still may not be the proper way to do this conversion, but I’m happy with the results. I’d still be curious to learn other ways to do this, however.
Cheers,
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I don’t believe I was, no. Should I?
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Compressor is really a powerful tool (as people say) as long as you set the Frame Control ON. Otherwise is more or less like using QT conversion for exporting.
You have all the reasons to set the Frame control ON.
– First because you are working with 10b material (ProRess) and Compressor only render in 10b when the Frame Control is ON (up to the Compressor manual).
– You are using Compressor for one of the most difficult tasks: To interpolate 6 new pictures per second.
And this is a critical operation. If you want to get a good result you need to set Frame Contol ON and “Rate Conversion: Best”. Then you will unleash all he power of the Optical Flow etc.
The problem is that the rendering time will skyrocket.
Cheers,
Rafael
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