Playout audio noise

General
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1

Good morning!!!

My video production setup uses a DeckLink Duo 2 card, configured with four output channels. The playback of video files, such as ProRes 4:2:2 or XDCAM HD 35Mb, and audio in Linear PCM, 24-bit, little-endian, 48000 Hz, works without any issues.

The only problem is with files that contain a 1 kHz reference tone, which generate continuous noises and clicks on the audio output.

My setup is
Linux GUI 22.04
CasparCG 2.4.3
Black Magic 15.0

I am attaching an example of the audio where the noise occurs so it can be analyzed and to check if the same behavior happens with you.

Thank for you time!!!

2

@Julusian
@didikunz

Have you ever seen this behavior in CasparCG?
I need to clear up this question in order to finish my Playout and put it into production.

Has anyone else experienced this behavior?

Thanks for the help.

3

Hello,

When listening to your video clip I cannot hear any clicking noise. How does your output look like? Are you embedding audio to sdi and deembedding? What is your setup.

4

So, when you play it through VLC or another player you don’t hear the noise, but when you play it through CasparCG outputting via a DeckLink Duo 2, in my case, the noise appears.

5

This is my setup channel

<channels>
    <channel>
        <video-mode>1080i5994</video-mode>
	    <consumers>
           <decklink>
  	          <device>1</device>
              <embedded-audio>true</embedded-audio>
              <latency>normal</latency>
              <buffer-depth>6</buffer-depth>
            </decklink>
         </consumers>
     </channel>
</channels>
6

I dont think decklink audio for 5994 framerates was ever foxed in 2.4, so this might be excpected. should work in the 2.5 betas I think thoough

7

@Julusian
Our system operates in 1080i5994.
We’ve conducted some tests and discovered that when we configure the DeckLink output to 1080i6000, the audio plays correctly; however, the reference signal from decklink is not detected.
We tried CasparCG 2.4.3 and 2.4.2, Ubuntu 22.04 GUI and Windows, Blackmagic Drivers 15.0 and 12.7.1, all with same results.
Even setting Screen consumer to 1080i5994 the audio clicks.

As you recommended we tried the 2.5 beta Win release 2025-07-04 16:48 with sucess, audio reproduces like a charm.

I have no idea how stable version 2.5 is or whether it would be reckless to put it into production