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Author Topic: Best place for 23.976 to 24 conversion for DCP  (Read 2636 times)

GrizzlyAK

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Best place for 23.976 to 24 conversion for DCP
« on: March 25, 2017, 07:08:39 PM »
I'm having a little trouble understanding what I'm seeing in Ae CS6 when importing a 23.976 fps DPX sequence into Ae using File | Adobe Dynamic Link | Import Premiere Pro Sequence.

I originally cut my footage in Pr CS6, sent it (as a 10-bit color DPX sequence) to Speedgrade CS6, where I graded it, and exported a new set of 10 bit color DPX files back out. I relinked them in Pr. I then imported that sequence into Ae using the procedure described earlier, and now have 12470 frames of 23.976 footage in my Ae project. If I do any of the following, I get a new comp at 24 fps with the same number of frames and same duration:

(1) Drop the footage onto the New Comp icon, creating a new comp that matches, then change the comp frame rate to 24
(2) Create a new blank comp at 24 fps, and drag the footage into that new comp
(3) Reinterpret the footage as 24 fps and drop it on the New Comp icon

All of these actions give me a new 24 fps comp with 12470 frames an a duration of 08:39:14, same as the footage. If I pull up all three of these new comps, and go to a particular time, say 08:00, in (1) and (2) I see the same image as in the original footage, but (3) shows me a different image, even though it shows me the same time and FRAME!

Now, if I create a new 23.976 comp and drag in the reinterpreted (24 fps) footage, and I pull up the same frame number (and time) as before, I see yet a different image. So, in all cases, if I pull up the same time and same frame number, I see different images. How can that be? I would expect the time to be off, but I would expect a frame to be a frame corresponding to a particular DPX frame in Pr making up the sequence. There are only 12470 frames in the sequence back in Pr. What am I missing here?

Also, what is the best practice (i.e., at what point and how) to convert a 23.976 project to 24 fps for DCP creation?

EDIT: So, after more testing, I've found that the 24 fps comp skips frame 999, and then again at 1999, etc. That's why the frames at the same frame number and time are different images. It re-labels the frames of the source when it eliminates the frames it must skip to maintain the overall length. I think I answered my first question, but still would like to know what workflow others use to convert 23.976 to 24.

Thanks,
Shane
« Last Edit: March 25, 2017, 08:36:05 PM by GrizzlyAK »

Terrence Meiczinger

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Re: Best place for 23.976 to 24 conversion for DCP
« Reply #1 on: March 29, 2017, 12:17:48 PM »
I think most people just export the frames as 23.976 and adjust the audio to compensate.

GrizzlyAK

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Re: Best place for 23.976 to 24 conversion for DCP
« Reply #2 on: March 29, 2017, 03:32:53 PM »
I think most people just export the frames as 23.976 and adjust the audio to compensate.

Do you mean create a DCP at 23.976 instead of 24? In OpenDCP, since we're feeding it an image sequence, does it just calculate the run time based upon the number of frames and the specified (you can do that right?) frame rate? If that is the case, then perhaps I can make that work by just creating the right length soundtrack and telling it it is 24 fps in OpenDCP. Or, is there something in the jpeg files that indicate frame rate or run length? I assume there is not.

After posting this, I did a bit more experimentation in Ae, which I've detailed on the Adobe Ae forums here https://forums.adobe.com/thread/2296461. There are still unanswered questions.

Thanks,
Shane

Terrence Meiczinger

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Re: Best place for 23.976 to 24 conversion for DCP
« Reply #3 on: March 30, 2017, 02:39:36 PM »
A DCP just has a number of frames and a frame rate. If you export your original material at 23.976 and create the DCP at 24fps, the number of frames stay the same, but it is played back at a slightly faster rate and will have a shorter duration. To compensate, you need to speed up your audio and adjust the pitch accordingly.

GrizzlyAK

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Re: Best place for 23.976 to 24 conversion for DCP
« Reply #4 on: March 30, 2017, 04:15:58 PM »
A DCP just has a number of frames and a frame rate. If you export your original material at 23.976 and create the DCP at 24fps, the number of frames stay the same, but it is played back at a slightly faster rate and will have a shorter duration. To compensate, you need to speed up your audio and adjust the pitch accordingly.

Got it! Thanks Terrence!

Again, thanks for all you've done for indie filmmakers!  :)

dcinemaforum.com

Re: Best place for 23.976 to 24 conversion for DCP
« Reply #4 on: March 30, 2017, 04:15:58 PM »