Audio overflow fixed in server 2.0.7

#1
When mixing multiple audio layers with levels that go near 0dB, or pushing the volume above 1, integer overflow may occur. This results in a very disturbing, crackling sound. Audio should be clipped in this case. Clipping is still a distortion, but anyway a LOT less disturbing than overflow. And clipping is what made rock 'n roll great ;-)

Because this bug bothered me (and our sound technicians) for years now, and because server 2.1.0 (where this is already fixed) is far from production-ready, I finally found time to delve into the source code and port this fix to server 2.0.7.

For those who can compile CasparCG, the modified audio_mixer.cpp can be found on github as
https://github.com/elanvrt/Server-1/blo ... _mixer.cpp

For anyone else, I put a fixed executable on Dropbox:
https://www.dropbox.com/s/qdzujgfr14aik ... g.exe?dl=0
No, you don't really need to create a dropbox account.

Just replace your existing 2.0.7 casparcg.exe with this one. Keep a backup of the original, just in case.
Chris Van den Bossche
ELAN graphics software developer
VRT television

Re: Audio overflow fixed in server 2.0.7

#3
Theo wrote:Hi Chris,
is it also possible to put an audiodelay in there, to fix audio offset problems with playback?
Hi Theo,

I'm sure it is possible if you find a programmer able to and willing to code it.
I am definitely not good enough with CCG code to do that. All I did was transfer a fix already done in 2.1.0 to 2.0.7, as 2.1.0 was yet too unreliable for on-air use at that time.
And time-shifting is also a totally different ballgame than simple real-time sample processing.
Chris Van den Bossche
ELAN graphics software developer
VRT television