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FCP and QT timecode discrepancy
So this one boggles me. There’s a large difference in the way FCP and QT are reporting durations on the exact same asset. BTW I’m running FCP 6.0.1, QT 7.2 and OS 10.4.10.
For example, we have a 23.98 DVCProHD non-drop frame sequence duration of 00:47:57:23 as stated in Final Cut.
It is then exported to QuickTime (also set to non-drop), however the movie properties state a different duration: 00:48:00:00.
Now if you take that exported QT file and import it back into Final Cut Pro it states the original duration: 00:47:57:23. So if anything this is a consistent value, I can go round trip on anything and it is always consistent.
It affects chapter markers too. The timecodes of the chapter markers in the FCP timeline are a slightly different timecode when you view it in QuickTime, again off by roughly 1/1000.
Has anyone seen this before? What is the reason for the offset?
Because of the QT difference the system we’re trying to implement is getting gradually farther and farther off.
Thanks!
Robert Longwell
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38 Replies
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I think the Duration in the Properties doesn’t work to good. Right now I have open a clip with the duration: 10.03.80 (?). However there two option in the prefernces that works right: “Show Time Code when available” or “Show absolute frame number”..
rafael -
I agree, the properties field does have some issues which I believe is simply a display issue. The data contained in the QT file, if extracted, is consistent with our findings.
So in our case even the QT timeline is inaccurate. My final frame is 00:48:00:00 frame 69051. FCP also states final frame is 69051. And if you include chapter markers and compare the time codes between QT and FCP they are off by about 1/1000.
Robert Longwell
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[Robert Longwell] “It is then exported to QuickTime (also set to non-drop), however the movie properties state a different duration: 00:48:00:00. “
Computers have no need for Drop Frame, you can tell QT to read DF but it does not
hence the difference in time indications. Using QT Ref files instead of full renders might help you.
gary adcock
Studio37
HD & Film Consultation
Post and Production Workflowshttps://library.creativecow.net/articles/adcock_gary/AJAIOHD.php
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Everything we do is non-drop. In which case then you’d think QT would be accurate? I’ve tried converting the TCs from drop to non-drop and vice versa, it never adds up.
Ref files are having the exact same issue as self contained.
Robert Longwell
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By the way 69051 frames converted is the following:
23.98fps drop: 00:48:00;19
23.98fps non-drop: 00:47:53:03So if anything it would appear as though QT is trying to express the duration in drop frame, but even then it isn’t completely accurate.
Robert Longwell
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Step through frame by frame, is QT displaying 30fps tc or 24?
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It won’t display the frames because an exported QT file from FCP does not contain a TC track.
So here’s basically what we have realized, QT is converting the frame count to TC by taking the video frame rate (23.98, 29.97 or 59.94) to calculate time code. This is why it is inaccurate.
QT should instead be converting frame count to TC by using the TC rate value (24, 30, 60) to calculate time code. When we apply that formula it perfectly matches FCP’s duration and marker TCs.
Robert Longwell
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You always get TC when you export QT from FC. Check it in the movie Properties.
You don’t get TC from FC when you export via QT conversion.
rafael -
Ever since quicktime 7.1.6, sequence timecode can be displayed from exported files as well s frame number and what the call ‘standard’. If you click the timecode at the bottom left corner you will notice the timecode turn into a drop down window. Have you tried this?
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Oops, rafael beat me to it.
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