click at reel change in multi reel dcp

[cgray999]

We're making our first multi reel DCP.
Client supplied the reels 4k ProRes 24fps 5.1 interleaved.
When QC'd by distributor they find single clicks at 2 reel changes.
They say click is very faint when playing in Clipster but louder when played back
in theater.

When we listen in the DCP o Matic player we can't hear any clicks.

Any ideas?
Thanks Cgray

[carl]

Can you make the audio MXFs from your DCP available?

[Carsten]

Do you have the project metadata file of that DCP? If so, please load it up here.
Maybe when you added the reels, you left a small gap. There is an extra option in timeline view (the 'magnet symbol') to make sure the reels follow each other seamlessly. Which version of DCP-o-matic did you use for this?

Another reason could be that the ProRes input reels are not perfectly aligned audio and video wise. In general, it is not necessary to create a DCP from reels. You could feed a contiguous ProRes file into DCP-o-matic, and let DCP-o-matic create reels if the DCP needs to be segmented. The input file can/should still be a single file. I don't think common video editors offer straight workflows for 100% clean reel segmentation, and setting them up manually can create errors.

- Carsten

[cgray999]

Thanks for the comments and questions

The client has to deliver a DCP with reels.
The DCP we made from the single Prores 5.1 interleave file is fine, no clicks.

Here's a link to the metadata and the mxf files between which are audio click.
https://fil.email/ukZspUX3

In case the folders are not preserved:
reel 1 is 6F2
reel 2 is 710
reel 4 is 32b
reel 5 is 964

Click between reel 1 and 2
Click between reel 4 and 5

I am now making a dcp with custom reels based on size.
Thanks
CGray

[cgray999]

Client decided a single reel DCP was ok.
I think the clicks must have come from
cutting the master in Premiere.
Thanks,
Christopher

[Carsten]

Yes, that's usually the problem. There are no tools in common video editing software to precisely chop audio and video with sample precision. Many people still seem to think that reel segmentation is a prerequisite to DCP creation. However, it is not necessary, and even if the DCP should be multi-reel, it is safer to do that within DCP-o-matic.

Some applications with subtitles need a DCP segmented due to subtitle reel size constraints.
However, even then, the source does not need to be segmented.

. Carsten

[Barak Epstein]

Christopher - I had this prob years ago and having it again this week. Can you tell me if your audio is 23.98 or clean 24?

[Carsten]

When clicks occur, I would always suggest to load both source clips, and the resulting DCP mxf aufio file into an audio editor (e.g. free Audacity will load MXF if the FFMPEG plugin is installed). That is usually the first step to see what has happend. Both at the joint, and overall (e.g. is the total length the exact sum of the individual reel lengths. Very often the reason is that the arrangement in DCP-o-matic is not accurate to the sample, or the reels have been cut without paying attention to precise frame boundaries. Some of these issues can be checked within DCP-o-matic by inspecting source properties.

- Carsten