SFZ "lochan" "hichan" opcodes support in Sfizz VST3 version

[josephernest]

Hi,
Congrats for this project!
With the following SFZ file, when sending a MIDI note 24 on channel1, both groups play at the same time, whereas only the first group should play.
It seems lochan=1 hichan=1 MIDI-channel-filtering does not work in the VST3 version (in Ableton DAW). I have tried both sfizz and sfizz-multi.

Any idea?

<control>
default_path=samples/

<group>
lochan=1 hichan=1
<region> key=24 sample=sine60.wav transpose=0 lochan=1 hichan=1
<region> key=25 sample=sine60.wav transpose=1 lochan=1 hichan=1
<region> key=26 sample=sine60.wav transpose=2 lochan=1 hichan=1

<group>
lochan=2 hichan=2
<region> key=24 sample=sine60.wav transpose=24 lochan=2 hichan=2
<region> key=25 sample=sine60.wav transpose=25 lochan=2 hichan=2
<region> key=26 sample=sine60.wav transpose=26 lochan=2 hichan=2

[jlearman]

Not sure it's possible, due to VST3 design abstracting the MIDI-ness out.

[josephernest]

@jlearman Thank you for your answer.

1. Is lochan / hichan working as AU plugin (Mac / Logic) to do the MIDI-channel filtering?

2. If not, what option exists on Mac to do MIDI-channel filtering (either with lochan / hichan or equivalent)? It seems that Sforzando doesn't implement lochan / hichan either, am I correct?

[jlearman]

Sforzando doesn't implement it at all. IIRC neither does Sfizz, regardless of plugin type. (When I posted the comment for VST3, I was thinking of hiprog/loprog. The comment is true, but it's not the reason.)

Here's a simpler test file:

<region> sample=*square lochan=1 hichan=1

It plays for all channels. I believe the idea is that these plugins expect you to load the plugin separately for each MIDI channel. The good news is that the I/O system should cache loaded file contents, reducing duplicate reads from disk. It doesn't optimize RAM usage, so any samples in both regions would be duplicated in memory. But with today's memory sizes, that's unlikely to be an issue except in very extreme and unusual cases.

[josephernest]

Thanks @jlearman for your answer.

Since lochan is not working, I think I will have to load multiple instances of Sfizz or Sforzando... The only problem with this approach is that any setting done in the GUI on instance #1 (label_cc20, label_cc21, ...), for example with:

label_cc20=Instr1
label_cc21=Instr2
label_cc22=Instr3

<group>
locc20=64
hicc20=127
<region>
sample=60.wav
...

needs to be re-done manually on GUI of instance #2, if we want both instances to play with the same settings.

[jlearman]

See also #1047

[essej]

There is no API mechanism currently in the sfizz engine to even pass channel in at all for input events... which is why this is not supported.