Author Topic: Intermediate VST Mixer causing UI performance hit on macOS  (Read 290 times)


  • Posts: 138

Hey Ian and gang!
Sooo.....I popped in an intermediate mixer for just VST streams on our macOS version just like I did in our .NET one and notice a huge performance hit graphically.
The time counters and playhead are moving chunky slow now.
instead of like 30 fps they look more like 10-15fps

the rough old code was like this

Code: [Select]
                    int stream0 = BASS_StreamCreateFile(FALSE, [aPath UTF8String], 0, 0, BASS_STREAM_DECODE);
                    int mixer = BASS_Mixer_StreamCreate(bass_info.freq, speakers, BASS_MIXER_NONSTOP);
                    BASS_Mixer_StreamAddChannel(mixer, stream0, BASS_SPEAKER_N(2) |BASS_MIXER_MATRIX);


and the new way is just adding this new 8 channel mixer in the middle

Code: [Select]
                    int stream0 = BASS_StreamCreateFile(FALSE, [aPath UTF8String], 0, 0, BASS_STREAM_DECODE);
                    mixer = BASS_Mixer_StreamCreate(bass_info.freq, speakers, BASS_MIXER_BUFFER);
                    mixerVST = BASS_Mixer_StreamCreate(bass_info.freq, 8, BASS_STREAM_DECODE  | BASS_MIXER_NONSTOP);
                    BASS_Mixer_StreamAddChannel(mixerVST, stream0, BASS_SPEAKER_FRONT);
                    BASS_Mixer_StreamAddChannel(mixer, mixerVST, BASS_MIXER_MATRIX);

Anyone have an idea (or tips how to fix) why adding a basic 8 channel mixer in the middle seems to be soaking the UI refresh rate so bad?
I should NOTE: Everything is working and playing correct.  It's just not looking like the buttery smooth application I had before this was added.  8(

thank for any tips!


Ian @ un4seen

  • Administrator
  • Posts: 20673
Is there an actual performance hit (eg. CPU usage increase indicated by BASS_GetCPU) or is it just that the reported position isn't as precise/granular as before? If it's the latter, please confirm which handle you are getting the position of, and how.


  • Posts: 138
Yeah it looks like if I change getting the position from steam0 to mixerVST it fixes the graphic chunky monkey issues and back to silky smooth.
Of course it just broke 20 other transport things....hahaha
i have a long day ahead of me repairing this, but I think I'll be alright now.  8)

Thx Ian!