Hello everyone, I recently used casparcg in TV broadcast but we had some problems with it. When showing bigger graphic like 70% wide and 70% tall there were some drops in audio and weird line glitch in top part of where graphic starts. Imidiately when layer was stopped the dropping of audio and weird line drop stopped. When played smaller graphics like bug or scoreboard it was without issue also. Interesting thing was that we didn’t see any problems in OB truck and satellite truck. Problem was reported from satellite subscribers around the world.
Setup:
1080i50 chain, reference locked everywhere
Casparcg with blackmagic decklink duo2 Fill+key
Blackmagic ATEM constellation 2ME 4K
Blackmagic chain (videohub, monitors etc)
AJA FS2 (for audio embeding)
Satelite truck (blackmagic atem + some encoder which I’m not sure)
From AJA also another signal into Blackmagic 4K Encoder and vmix server for SRT encoding (no issue shown there)
What we tried regarding configuration of casparcg output
1080i50 screen
1080p25 screen
1080p50 screen
1080i50 screen >> Decklink 1080p25
When I turned off casparcg and run Vmix with same graphic file and 1080i50 output it was working without problems.
Sounds quite weird. In analog days there were sometimes similar problems when the video level was too high. But I never heard of something like that in the digital world. But maybe it’s something, that happens on the receiving end of the satellite transmission. Has your graphics very saturated colors or much white? Or has it a lot of detail, that makes the encoder go wild?
Time to bringout the expensive measurement devices.
Feels to me like a illegal out of gamut color.
what you could do for start is put your working vmix output into a videomixer together with your not working caspar output and make a vertical or horizontal wipe to see if you see any differences.
There is an open-source video analysis tool that can detect and report many signal issues including gamut errors. The tool is called QCtools and it is available for multiple platforms from here.
The tool looks at files so checking the large area template requires a video file of the output. This is simple to acquire using a spare Decklink input with the MediaExpress tool installed as part of the Decklink driver. A two second recording is sufficient using an uncompressed codec.
The Broadcast Pixels filter can add a highlight colour of your choice to show the out of range areas of the video frame.
If you have a frame synchronizer with a built-in legalizer, you can pass the signal through it to clear any potential issues. Since your AJA FS2 appears to have a legalizer, enable it in YUV mode.