Managing multiple concurrent DCPs

[boxerab]

Hello,
I am curious about how DoM is supposed to work when user tries to generate multiple concurrent DCPs.
How it works currently for me is:
1. create a new film
2. add a file
3. begin making a DCP

Now if I create a new film, this succeeds, but I am not able to add a file
to the new film until the first film is finished creating a DCP. Is this how it is supposed to work ?

If so, should the user be notified that they can't add a file until the current DCP is complete ?

Thanks,
Aaron

[Carsten]

There is a batch converter that works in the background. If you are finished setting up a DCP, send it to the batch converter, and DCP-o-matic main is ready to work on a new DCP.

->Jobs->Make DCP in batch converter

Batch converter uses a job queue, where you can control all running/pending conversion jobs. Batch converter is part of a normal install, except for Mac OS where you need to download and install all apps making up the DCP-o-matic environment separately.

As a matter of fact - there is a 'poor peoples' batch converter in DCP-o-matic main. You CAN setup a new DCP while another one is currently encoding. It is possible to start an encode, then create a new project, add files, etc. It's a bit more limited than using the batch converter. I use it often for a series of short slide DCPs which take only a few seconds or minutes to complete. I send one slide to conversion, then immediately setup the new one. When the previous one has finished, I am usually ready to start the next conversion. Depends a bit on the CPU speed/conversion time wether that works sufficiently or not. It may only be an option for slides.
Usually, the real batch converter is the way to go.

You may be right that the option to create a new project should be greyed out during a conversion. But that would break my personal slide show workflow. But maybe I should use batch converter for this task anyway.

[boxerab]

Batch converter uses a job queue, where you can control all running/pending conversion jobs.

Thanks, I have played around with the batch converter. Is batch designed to run while main DoM is also running ?

[Carsten]

Yes. If necessary, DCP-o-matic will start batch converter automatically when you send a job to it's queue.

[boxerab]

Thanks. Is is possible for two encoders to run concurrently ? Hopefully this is not possible, as there would be no advantage to it,
and possibly harm performance.

[Carsten]

Usually, the second encoder task will get no access to the encoder process. You will see an error message about that. Depends a bit on wether you use the internal encoder of the app, or if you use the external encoder/server. DCP-o-matic has setup options for number of encoding threads for both the internal encoder and the remote encoding server. Note, the remote encoding server may run on the same machine as DCP-o-matic or batch converter itself, thus serving local encoding through local IP connections.

[boxerab]

Thanks, good to know. Why would you run a local encode server rather than the internal encoder ?

[Carsten]

At some point in time, it was possible to get a higher encoding performance using the internal + the encode server running on the same machine. On specific machines at least. Server processors, many cores. Not anymore, as far as I know. We also had the idea to build a GPU based encoder as a small encoder-only module. As a non-open-source software (due to possible license issues), it could be kept separate from the open-source main software. In that case, you could have the standard open-source software with it's normal software update cycle, and have a separate fast GPU encoder with it's own lifecycle on the same machine, or, as originally intended, as a network encoder.