[FFmpeg-user] Replace multiple parts of audio with beeps

[Alexander Bieliaev]

How can I replace multiple parts of audio with generated beeps?
I tried next command:

-filter_complex "
[0]volume=0:enable='between(t,10,15)+between(t,20,30)'[main];
sine=f=800,
pan=stereo|FL=c0|FR=c0,
volume=0:enable='between(t,0,10)+between(t,15,20)'[beep];
[main][beep]amix=inputs=2:duration=first"

It successfully replaced parts between 10 - 15 seconds and 20 - 30 seconds
but the beep keeps playing till the end of the audio.

-- 
This email and any files transmitted with it are confidential and intended 
solely for the use of the individual or entity to whom they are addressed. 
If you have received this email in error please notify the system manager. 
Please note that any views or opinions presented in this email are solely 
those of the author and do not necessarily represent those of the company. 
Finally, the recipient should check this email and any attachments for the 
presence of viruses. The company accepts no liability for any damage caused 
by any virus transmitted by this email.