Hi, I have multiples ixus160, I use with chdkptp+mc+usb remote; there is way to download the picture directly without saving to SD card? like remoteshoot+remote_sync with multicam.lua?
There isn't.
chdkptp only operates on one camera at time, so coordinating remoteshoot over a bunch of cameras would quite complicated, and the actual download operations would still be sequential.
The performance benefit would also decrease with the number of cameras: The main advantage of remoteshoot is that it avoid the time required to write to SD, but in multicam, all the cameras write to their respective SD cards in parallel.