Audio popping when using Decklink HD and Redcast Intime

This may have been addressed previously in this forum but I am getting little “pops” or “crackles” in my audio output from a Decklink HD Extreme HD 3D+ when playing Redcast Ontime. I can play the same files over and over again and get different crackles (or even no crackles). My current video/audio file settings are:

frame rate: 29.97
audio bite rate:64
sample rate: 44.1

The crackling is not loud, just annoying. Any ideas?


Have you tried with 48kHz samling rate? Caspar is TV-broadcast gear and that is always 48kHz uncompressed. If you play a WAV file with 16bit-Stereo and 48kHz and the crackles are still there I would replace the Decklink with a newer model.

I am trying 48 now. Thanks!

So, I have an update on this … the popping and crackling is specifically when outputting 1080i at 59.94fps. As you may know this a major output format in the US. There is no crackling at 60fps or 30fps. Very clean. As a file we are encoding at 1080i 29.97. Any ideas?


I have switched to a new decklink card but have the same crackling.

Which version of CasparCG server are you using?

The version of CasparCG server appears to be 2.1.0, It is dated 6/12/18. I haven’t tried 2.2.0 The build was included in the latest version of RedCast Ontime. The crackling is intermittent (as is, it can happen on the same file, then doesn’t) and at mostly low level audio level. I have a version of CasparCG client 2.0.8 I have tried that creates the same problem (with server build 2.0.7). It doesn’t appear to “crackle” at any other frame/field rate.

Files are being encoded in H.264 1080i 29.97fps at 48khz sample rate. I thought it could have been my older decklink card, but I have since updated to a new Decklink SDI 4K and have the same problem.