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720p59.94 to 1080i29.97
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Okay, that’s FCPs way which I wouldn’t trust as working as any other converter in the world. FCP lays out 24p material on a 29.97 timeline as 2224.
I will have to do this test when I get back to the office with a cross convert.
Chrispy, do you have your answer yet? 😀
Jeremy
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[JeremyG] “Okay, that’s FCPs way which I wouldn’t trust as working as any other converter in the world. FCP lays out 24p material on a 29.97 timeline as 2224. “
Don’t want to toot my own horn, but I am the one who originally pointed out the 2224 thing with version 6. I also pointed out how it scales between 480 and 486 instead of cropping (a bug which didn’t exist in FCP 5). FCP6 doesn’t convert everything right. But in this case it does.
I can PROMISE you this is the way 60fps 720p is meant to be converted to 1080i. No other way. Think about what the image would look like on a display if it worked the way you described. It would blend mismatched fields together. Pure filth. Might as well make a 3/4″ SD tape because it wouldn’t look any better. Trust me, it doesn’t work that way.
If you do find a converter that does it this way then it is wrong, and FCP6 is right. But I’m 100% certain you will find any converter that does it that way. Not a Kona, not a Teranex, nothing.
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Cool.
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[Sean ONeil] “That is a true 1080i60 interlaced quicktime video. Notice how every other frame has been omitted. That is how it works.”
You should NEVER allow FCP to do any sort of these conversions for you or else you end up with mistakes. This is why you want a hardware converter such as the AJA Kona 3 which does this conversion in realtime and perfectly cleanly each time.
What you’re seeing here is the result of FCP not properly converting 720p/60 to 1080i/29.97.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR
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[walter biscardi] “What you’re seeing here is the result of FCP not properly converting 720p/60 to 1080i/29.97.”
Wrong. Why don’t you guys post clips of the Kona 3 doing the conversion. Then we can all see how it does it the same exact way.
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[Sean ONeil] “Why don’t you guys post clips of the Kona 3 doing the conversion.”
No worries, I will once I get back to the office and I will prove myself wrong.
Jeremy
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I just did it w/ a Kona 3. I don’t have an HD deck in house, so I just fed the SDI to another NLE. 720p timeline, used the Kona control panel to do a 1080i cross conversion.
On the other machine, I just captured 1080i using capture now. I’ll post the QT in just a few minutes.
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After all that, I stand corrected. To my shock the Kona 3 does convert it the way Jeremy described. I completely understand the situation now. Sorry for the attitude and pardon my ignorance. This is how I learn things. It has been a really nasty day and I’m on some kind of weird medication (seriously). But I still stand by my assertion that the FCP6 method is superior.
The Kona 3’s method preserves the temporal quality at the cost of spatial quality. It keeps it at 60fps by literally chopping the resolution in half. So while you maintaining the 60fps, you only get 540 lines of video instead of 1080. The idea is that it gets played back at 540p60 on a consumer television after being processed by the video decoder. I think it would almost be more technically appropriate to call it 540pSF instead of 1080i. This video cannot be presented in interlaced format. It must be processed/deinterlaced. If you watch it on your broadcast monitor you’ll notice how awful it looks without being processed.
FCP, Motion, and AE instead preserve the spatial quality. So you get a full 1080 lines of video per frame. But it must cut the frame rate in half and make it 30.
In other words, this is a creative decision. A matter of taste or preference. I’d bet a Teranex allows both options. But it is my strong opinion that the FCP method is better and safer, and I think it’s pretty lame that the Kona can’t do either or. I’m not sure all consumer equipment can properly decode this 540psf-type signal that the Kona creates. Maybe it does. It should be noted that the FCP method is much more difficult to process, since it involves upscaling to 1080p first, then throwing away ever other frame.
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Thanks for posting this and following through. I don’t see one as better or worse, just different. The FCP method might produce less convincing motion (since the original material is scanned 60 frames per second, then you throw half of that out). Creating 60i material from 60p is almost the same as shooting @ 1080i if you ask me. It’s two fields of 540 lines that are 1/60th of a second apart that when combined make up a 1080i frame.
Jeremy
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[JeremyG] “It’s two fields of 540 lines that are 1/60th of a second apart that when combined make up a 1080i frame.”
Well after the conversion there’s only one field so there’s nothing to combine. The Kona conversion omits the other field. So you are left with sixty “half-frames”, which when played back properly becomes 540p at sixty frames per second. The full 60fps is maintained but it is only half the resolution of 1080 lines (although in the case of converting from 720p, it would be more like 2/3rds the resolution). Note that the FCP Canvas uses the same method during playback – it omits every other field (cutting the res in half) so you never see jaggies. Does it with SD as well.
The FCP 720p-1080i method is completely different. Instead of cutting the resolution in half by chucking away one of the fields, FCP instead chucks away every other frame (like I thought everything did) – but keeps the full 1080 lines for each frame. So it is essentially 1080p at thirty frames per second. Higher res but half the framerate.
I see wisdom and folly in both methods. It’s just robbing Peter to pay Paul or vice-versa. I do wish the AJA Control Panel allowed both options, and I wish the FCP preferences did as well. And I wish the manuals for both products would explain this stuff so that you and I wouldn’t have to waste time discovering it ourselves. Anyway, I feel smarter now. Good to learn new things.
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