Decklink audio output is broken with NTSC or 59.94 setup

[sendust]

Expected behaviour

Test Tone singal playback should be clean

Current behaviour

Test Tone singal playback is not clean when casparCG is setup with Decklink NTSC or 1080i5994
Playback with PAL or 50, 60 configuration is fine.

Steps to reproduce

1. Create test tone signal with ffmpeg
   ffmpeg -f lavfi -i testsrc2=rate=29.97:duration=60:size=1920x1080 -f lavfi -i sine=frequency=1000:sample_rate=48000:duration=60 -af volume=-30dB -c:v mpeg2video -b:v 20000k -c:a pcm_s16le tone.mov
2. setup CasparCG with Decklink, NTSC
3. playback generated test signal
   play 1-1 tone
4. Listen HDSDI or AES audio from Decklink (Volume up)
5. You can hear abnormal tone sound with NTSC or 5994 setup

Environment

• Commit: d442a8f and later
• Server version: [v 2.3.0]
• Operating system: [Windows 10]
  Decklink Driver [10.11.4 ~ 11.5.1]

with PAL or 50, 60 configuration, tone signal playback is perfect

You can check recorded decklink output here

Normal [PAL, 6000]
https://youtu.be/77crz2iHc5g
https://youtu.be/yaKXQ8g2YE0

Abnormal [NTSC, 5994]
https://youtu.be/ftGc4xQ8OgE
https://youtu.be/Xvi4Weer888

[hamuchen]

I can confirm this issue. Any updates, because the linked Issue #1326 seems fixed?

We are stuck on 2.0.7 because of the audio issues with every version after that with 5994.

Cheers,
hamu

[dedicatedbroadcastsolutions]

I am having the audio crackle issue with 2.4.2 stable at 1080i5994 and 1080p2997 rates. We need some fix to this or this program becomes unusable for broadcast without frame rate converters in hardware. This is effecting both screen and decklink outputs.

2.3.3 LTS Stable seems to have this issue fixed FYI