Is there way to recognize playing music in host?

i am studying and developing vst plugin.

i have wondered 

"    void processBlock (AudioSampleBuffer& buffer, MidiBuffer& midiMessages) override"

i try this, it was called after i added to the channel.

so this means that if i did not played that track, vst plugin process that data ( 0.000000, 0.0000000)

do i have right concept??


or is there any concept or way to recognize the track playing??

Sorry, your engish isn't so great, and I'm stuggling to understand what you're asking...

But in general the answer to questions of the type "Does the host do [x]?" is that hosts are all different and will do things their own way. There'll always be a wierd one that does things in an unexpected way.

if i add my plugin, (i dont play track yet.)

but "processbloack" function is called.


so  i wondered that is there any flag something like that?

i want to get data not 0.000000

do i make flag my own?


You'll get whatever data the host chooses to send you. Not sure what kind of flag you're expecting there to be?

looks like they're asking if there's some sort of flag sent to the plugin when a block is silent.  I would have to assume the answer is no. 

plugins don't add latency do they (unless you build it in, for some reason)?  I would assume they just process the block in series, at the same time as the host's audio there would be literally no way to know if i block is silent or not, without making at least 1 block delay.

does that sound about right?


i have the same idea too.

i wonder exactly,  if i play pure sine wav file via daw(cubase, reaper)

so are there any differces with original wav file and sum of buffer(through daw).



Sorry, but I really have no idea what you're all trying to say/ask!

sjnam asked "Does the host notify you if the block to be processed is silent (presumably for an effect plugin)?"

i answered "No, i doubt it."



Well, it can be done this way:

inside processBlock():

AudioPlayHead* playHead = getPlayHead();

Then the playhead can be used to retrieve information about the current playing condition:

CurrentPositionInfo pos;
playHead->getCurrentPosition (pos);

now, the pos struct contains a lot of useful information one of which is 


which is a boolean telling if the host is idle or currently playing the song.

Check this page for the documentation of CurrentPositionInfo:


thank you! your reply!

this is what i want to know it.

i spend the time about a few days.

you save me.


thank you again.