Cutting MXF file

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edo1080
Posts: 4
Joined: Thu Feb 07, 2019 11:27 am

Cutting MXF file

Post by edo1080 »

Hi, don't know if this is the proper section, but I am trying to write a tool which cuts an MXF file given the CPL entrypoint and duration data.

It depends on the essence (Video , audio or metadata) of course, but I know asdcplib has something useful in the code.

Is there a developer forum where I can discuss it?
carl
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Joined: Thu Nov 14, 2013 2:53 pm

Re: Cutting MXF file

Post by carl »

Hi,

There's no developer forum; here is fine if you want to talk about it.
edo1080
Posts: 4
Joined: Thu Feb 07, 2019 11:27 am

Re: Cutting MXF file

Post by edo1080 »

thank you for your kind reply,

The aim is to export one MXF file from DCPs which are splitted in reels, one MXF for video, one for audio and one for Atmos when present.

I've quickly read inside the ASDCP library, I'm focusing on Atmos which seems to be the hardest part, I have seen there's a method 'readframe', which should be supposed to read a portion of file corresponding to a frame. I siplmy wonder if the workflow I have to do is unwrap each reel and rewrap the whole joined essences in one big mxf reel, or read a portion of MXF file from byte x to byte y and join.

Thanks in advance
carl
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Joined: Thu Nov 14, 2013 2:53 pm

Re: Cutting MXF file

Post by carl »

I think you are right in your approach to use 'ReadFrame' to get the data, then write it out to a new MXF. Whether this will work for Atmos is anybody's guess, but one would guess that Atmos data can be chopped up like this.

If you want an off-the-shelf solution it should be possible to (ab)use DCP-o-matic to do what you want; make a project containing your DCP, keep the reel mode as "single reel" and it may give you what you want...

If you want to code your own thing, it might be worth looking at libdcp. This provides a slightly higher-level interface to DCPs than asdcplib.
edo1080
Posts: 4
Joined: Thu Feb 07, 2019 11:27 am

Re: Cutting MXF file

Post by edo1080 »

WOW, the off-the-shelf solution sounds the best one; but let's say the DCP is encrypted and I can provide a DKDM for it.

Can I import it in DCP O Matic and provide a DKDM for it? It's not clear to how to import and encprypted DCP in a new project...

I mean have I to import CPL, right and add DKDM for it, or first DKDM and then CPL? OK, will try... never thought about this solution


Edit: tested import of encrypted DCP and it works. Will try with the test DCP I mentioned before and report
Carsten
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Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Cutting MXF file

Post by Carsten »

Can see no reason why this shouldn't work by simply importing a multi-reel DCP into DCP-o-matic, and exporting it as a one-reel DCP. For the ATMOS part, I don't know, I understand Carl has worked a bit on ATMOS (pass through) support recently, but don't know to which extent.

- Carsten
edo1080
Posts: 4
Joined: Thu Feb 07, 2019 11:27 am

Re: Cutting MXF file

Post by edo1080 »

Yes, it works with a standard DCP, I don't know about the atmos part, but I'll try and report here as soon as I have some time
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