DCP from a still image - Play Length won't change

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brianpdavis
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DCP from a still image - Play Length won't change

Post by brianpdavis » Mon Mar 11, 2019 12:04 pm

I'm trying to create a holding image DCP from a still image. I'd like to use a single TIFF image which is encoded as a single frame and then repeated therefore the encode time should be much quicker and the file size of the DCP is kept small.

According to the DCP-o-matic Manual it appears this can be done by changing the Play Length setting in the Timing tab. Unfortunately for me the Play Length setting does not appear to be modifiable. It just states a default 00:00:10:00 which I am unable to change.

What I need is a still image that stays on screen for say 1 hour or until it's nudged on by the projectionist.

carl
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Re: DCP from a still image - Play Length won't change

Post by carl » Mon Mar 11, 2019 12:13 pm

Try altering the "full length" time; that should do what you want.

brianpdavis
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Re: DCP from a still image - Play Length won't change

Post by brianpdavis » Mon Mar 11, 2019 12:30 pm

The problem with that is it encodes a rather large file size DCP.

Is there any way of just looping or holding on that one frame indefinitely until prompted off by the projectionist?

Any idea why the 'Play Length' is not changeable as it is in the manual Figure 4.3?

Image

carl
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Re: DCP from a still image - Play Length won't change

Post by carl » Mon Mar 11, 2019 12:34 pm

I think that's a mistake in the manual: I will check.

There's nothing in the DCP spec that allows a DCP to pause itself, sadly. You could probably use an automation cue on the projection server, or the projectionist could start the DCP and then pause it themselves.

In the future DCP-o-matic may get an optimisation where it does some smart stuff to reduce the size of DCPs like this.

brianpdavis
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Re: DCP from a still image - Play Length won't change

Post by brianpdavis » Mon Mar 11, 2019 12:40 pm

Thanks for the quick response.

It was the wording from the manual that got me excited ... "This will be much quicker than creating a DCP from a video file, as DCP-o-matic only needs to encode a single frame which it can then repeat".

I guess it does only need to encode a single frame - but it also needs to duplicate those frames which ultimately results in a large file.

Maybe this is one for the projectionist to handle for now.

Many thanks for the great work.

carl
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Re: DCP from a still image - Play Length won't change

Post by carl » Mon Mar 11, 2019 12:42 pm

Yes, sadly that remark refers to encoding speed, rather than the size of the result. One day there will be a nice (-ish) way round this.

Carsten
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Re: DCP from a still image - Play Length won't change

Post by Carsten » Mon Mar 11, 2019 1:00 pm

We have been talking about re-referencing content in the DCP-CPL before, however, so far it seems there is no easy way to do this within the current GUI and methods of the DCP-o-matic main app. Currently, if the content allows, you should try to set the encoding datarate as low as possible (usually no problem with 'simple' slides (e.g. logo), and also choose only 2 audio channels. That should keep the DCP reasonably small.
Occasionally, I do long DCPs on a black background using timed-text subtitles. The datarate for black is very low, and the timed-text doesn't eat anything.
It could be done now with timed PNG subtitles in a similar fashion. Carl, any progress in supporting standard image files as a source for PNG subs?

Some people also modified DCPs into multi-reel compositions by hand. It is actually not that complicated to do. You create a DCP in DCP-o-matic in as many reels as you like, split by content. Just add the same picture as often as you need (e.g. 1min, right-click->repeat 59 times=1hr). In the final DCP, there will be 60 reels, but each reel taking the same amount of space. Now, all you need to do is to search/replace reels 2-60 with the first asset, so only the first asset is reused for 59 times. Same for audio, even if it is silent. You would do that in a text editor. Yeah, it's a bit of an effort, but afterwards, you can throw away video and audio reel assets 2-60 and save that space.

If possible, I would create a short DCP and have the projectionist put the server into play-pause - that will keep the slide up forever. On some servers, this is also possible automatically or by remote means (button, VNC client, etc.). Some servers also allow to play multiple CPLs sequentially 'nearly' seamless. I haven't tried recently on a Doremi, but it could work, referencing the same short CPL in a ShowPlaylist multiple times. Maybe there will be a short 'blink', maybe not.


- Carsten

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