Export DCP Error

[skiff]

Hi everyone!
I try to export a DCP but it writes to me: Error: could not allocate FFmpeg format context.
I need to install FFmpeg? How to do it?
I can choose parameters for the MP4, like resolution and data rate?
Best
Skiff

[Carsten]

What version of DCP-o-matic, and which operating system?

No, you do not have to do a dedicated FFMPEG install to use the export function, but it may be that your DCP-o-matic installation did not succeed (partially).


No, you will not be able to set resolution/data rate. The export uses fixed parameters, in part from the active project settings (2k/4k, container, etc.). If that doesn't fit your needs, you have to use a tool like handbrake to convert into other formats.

That error message popped up on the forum before:

https://dcpomatic.com/forum/viewtopic.php?t=806

Is it possible you are still running an early 2.11.x test version?

- Carsten

[skiff]

First thank you Carsten! Hope you will help me.

I updated today from the 2.10.5 Version to 2.13.3.

I am using macOS Sierra 10.12.16
MacBook Pro 15' late 2013
2.3 GHz intel core i7
16 GB 1600 MHz DDR3
500 GB SSD

[Carsten]

Hrrrr... there is stinky little bug in DCP-o-matic - you need to specify an output filename first before clicking 'OK' on the export dialog.

I am using exactly the same hardware and software as you do.

I just filed a bug on mantis: http://dcpomatic.com/mantis/view.php?id=1260

- Carsten

[skiff]

&2$39/'bs38$$
Yes now is working...
For low quality MP4 you recommend HandBrake?
It's keeping the Timecode from the DCP?
I need it for sending to subtitles editing, for electronic subtitles (external screen under the main frame)

Thank you!
Skiff

[Carsten]

You can also use the MP4 directly that DCP-o-matic creates. If it needs to be smaller, handbrake will do it. You should take care that the frame rate is not changed during conversion, but, there is little risc for complications. The trouble is, most of Handbrakes default conversion profiles force a frame rate change. You may need to define your own profile that creates a lower resolution, but keeps the frame rate 'as source' and at 'constant framerate'.

I created an 'MP4_shrink' preset by modifying the legacy 'Universal' preset to constant framerate / same as source, 720*390, AAC passthrough.


- Carsten

[skiff]

Thank you Carsten

But HandBrake 1.0.7 doesn't let me Open Source DCP package.
It wrote to me: Source: no valid source found.
Do I need any plugin?

Best
Skiff

[Carsten]

No, I mean, you need to export to h.264/MP4 from DCP-o-matic, then use Handbrake to shrink that MP4 to a lower resolution.


I have attached a suitable handbrake preset. You can import it into handbrake. It reduces a 1998/1080 video to 720/390, keeps framerate, and passes through AAC audio.

- Carsten