BlackMagic DeckLink Implementation Questions

[pasantru]

Hello,

I’m currently implementing a solution as a university project to replace a professional playout and recording server using BlackMagic DeckLink Mini Monitor 4K and Recorder 4K cards. I have several questions and hope to get some clarification.

Current Status:

• Playback is working smoothly under Debian and Ubuntu

• I’m using CasparCG for playback

Issues I’m Experiencing:

1. Recording Problem: I haven’t been able to record directly from the Mini Recorder 4K. I understand I need to add it as a consumer device in the configuration, but even with a valid HDMI source connected to the recorder, the output shows only a black screen. I know I’ll need to use FFmpeg commands to process the recording, but I’m stuck at this initial stage.

2. GPU Requirements: Is a dedicated GPU necessary for basic playback? I’ve been using my CPU’s integrated GPU and it seems to work fine, but I want to confirm this is acceptable for production use.

Given my challenges with recording through CasparCG, would you recommend implementing recording separately using FFmpeg directly, while keeping CasparCG solely for playback duties? Or should I persist in getting the integrated recording solution working?

I’m relatively new to professional video workflows, so any feedback or guidance from experienced users would be greatly appreciated.

Thank you!

[didikunz]

@pasantru

Recording Problem: I haven’t been able to record directly from the Mini Recorder 4K. I understand I need to add it as a consumer device in the configuration, but even with a valid HDMI source connected to the recorder, the output shows only a black screen. I know I’ll need to use FFmpeg commands to process the recording, but I’m stuck at this initial stage.

You don’t need to add it in the config, and also not as a consumer. A consumer is an object, that consumes frames from the pipeline and usually outputs it. An input device is a producer (produces frames for the pipeline).

So the trick is to play the Decklink input on a layer at a channel. This channel can have a Decklink (or screen) attached to it, but it can also be virtual. then you issue a command to record this channel. Something like:

PLAY 1-10 DECKLINK DEVICE 2 FORMAT 1080i5000

ADD 1 FILE “Output.mov” -vcodec libx264 -preset ultrafast -tune fastdecode

@pasantru

GPU Requirements: Is a dedicated GPU necessary for basic playback? I’ve been using my CPU’s integrated GPU and it seems to work fine, but I want to confirm this is acceptable for production use.

AFAIK no.

@pasantru

Given my challenges with recording through CasparCG, would you recommend implementing recording separately using FFmpeg directly, while keeping CasparCG solely for playback duties? Or should I persist in getting the integrated recording solution working?

I would use CasparCG for both tasks. When you run into performance problems you can also run two separate instances of CasparCG server. Please make sure, that they have individual configs, that allows you to change the AMCP port for the second one.