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Author Topic: Help needed with extra frames in Audio MXF  (Read 2686 times)

whtblsh

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Help needed with extra frames in Audio MXF
« on: January 16, 2017, 12:47:10 PM »
Hello! I just finished my first DCP and came across extra frames in the audio MXF.

145152 frames for video MXF
145297 for audio MXF

I was forced to cut off the extra frames in the audio MXF to make the DCP work but am concerned the whole project is off sync now.

We shot and edited in Premiere at 23.976 and exported out of After Effects to get 16 bit quality, then I had 145152 frames.
I used Open DCP and noted 24 fps where it encoded the Tif conversion to JPEG2000 and it also preserved the 145152 frames.
Everything went smoothly until the part of extra frames in the audio MXF which is 24bit/48Hz.

I am confused about which number of frames is accurate, 145152 or 145297, I thought there are just the same number of frames in your movie no matter what frame rate you change it to so I don't see why it is necessary to have extra frames at 145297 when I export audio MXF.

Please does anyone have a solution that does not require me to re-export and reconform the whole TIf sequence again at 24? If so, what is the best way to do it without getting jittery footage or weird extra frames or artifacts? I read that Premiere has a tough time changing footage from 23.976 and dropping it into a 24 fps sequence.


darklover

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Re: Help needed with extra frames in Audio MXF
« Reply #1 on: January 16, 2017, 01:34:42 PM »
hello,
145152 *24 / 23.976 = 145297

you have to modified speed of wav files. with a rate of 100.001..%
if you use a windows plateform , you can use sox library : (  http://sox.sourceforge.net/ )

sox "directory\inputwav.wav" "directory\outputwav.wav" speed 1.001001001

rewrap audio in mxf file (24 fps)
re-do xml dcp.

picture duration = number of image / edit rate
audio duration = number of audio samples

whtblsh

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Re: Help needed with extra frames in Audio MXF
« Reply #2 on: January 16, 2017, 03:41:42 PM »
I tried to download the software for sox program, but it doesn't install all the way on my PC. It just has the exe file and then it doesn't do anything. Any suggestions on how to get this program? Maybe it isn't compatible with my Windows 7?

whtblsh

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Re: Help needed with extra frames in Audio MXF
« Reply #3 on: January 16, 2017, 03:45:16 PM »
It may be that this program requires more higher level tech skills ie typing commands via terminal. I am a more basic computing person so is there another program that is more user friendly in which I can change the speed of the Wav files?

darklover

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Re: Help needed with extra frames in Audio MXF
« Reply #4 on: January 16, 2017, 04:29:03 PM »
yes !
you can use "Audacity"    https://sourceforge.net/projects/audacity/

Open your(s) wave file(s) (File-> Open) and read direct the wave file.
Then in Effect Menu -> Change Speed    :
    Put this value : 0,1001001 ( % )
OK

Then Export the file :
File -> Export AUdio
(in the dialog box click: "Options") and choose : WAV microsoft (head)
codage : 24 Bit signed PCM  (Important)
Then : OK
give a new name (ex: Myfilewav24fps)      CLick on "SAVE" .

do it for each tracks   or your single wav file.

whtblsh

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Re: Help needed with extra frames in Audio MXF
« Reply #5 on: January 16, 2017, 04:35:22 PM »
Ah I am exporting on Audacity, but I don't think that is the right percentage change.

I saw that I have extra 145 frames from 145152 vs. 145297.

so the exact percent change is 145/145297 = 0.0009979559 or 0.001% and then exporting this, because I want it to increase the speed by .001% approximately.

Is this wrong? What is this number you have? '0,1001001 (%)' I'm not sure I understand that.

darklover

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Re: Help needed with extra frames in Audio MXF
« Reply #6 on: January 16, 2017, 04:53:59 PM »
http://i.imgur.com/ahiARGt.jpg

1 : 01h40 54 '' 42 ms  =   6054,042 secondes  *24 fps =  145 297 durations

2 : change speed 0.1001001

3 : result : 01h40h 48''   = 6048 secondes * 24 fps =    145 152 durations
« Last Edit: January 16, 2017, 05:11:09 PM by darklover »

whtblsh

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Re: Help needed with extra frames in Audio MXF
« Reply #7 on: January 16, 2017, 08:09:41 PM »
Great, thanks! Now it is exported at the same length of 1 hr 40 min 48 seconds as the video will be at.

I also had additionally to decrease the pitch in Audacity Effects option so that the sound is not sounding off like a 'chipmunk' so I decreased the pitch by the same amount at -0.1001001 since it was sped up I wanted to slow it down by the same amount.

https://www.youtube.com/watch?v=cEN_X8u_Ygk (audacity tutorial on this)

Now I will go ahead and rewrap the audio in the correct length. Thanks for all your help!








Terrence Meiczinger

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Re: Help needed with extra frames in Audio MXF
« Reply #8 on: January 16, 2017, 10:20:26 PM »
Thanks for helping Darklover.

dcinemaforum.com

Re: Help needed with extra frames in Audio MXF
« Reply #8 on: January 16, 2017, 10:20:26 PM »