Would it be possible to have an additional mode to client, local, local & client. This new mode could be something like local with client feedback.
The idea is, for small devices as RPi or any other small devices with poor wifi connection, to have a "capture and store" in local and a feedback on client side under the form of a light jpeg file to display and control the capture.
In client mode when the raw file is huge (several Mb) the transfer time with wifi is also huge and as the capture and display process are synchronized it takes a while to chain many exposures.
In client/local mode the problem is identical.
In local mode there is no lapse due to the transfer to client but there is no control of what is captured.
The new suggested mode could allow to store the captured image in local mode and to display & control the capture on client side without the inconvenient of a long transfer via wifi.

I'll second this request. I've had to turn off image previews (both FITS and DSLR) in order to shoot sequences rapidly. If I keep preview on, it can take a couple minutes between and before the next sequence frame is shot, due to the preview downloading. IMO, this essentially rendered the entire system useless until I figured out how to turn off preview, but now I'm shooting blind - which I can live with, but is far from ideal. OR, are we missing the solution that's already in the software?

Thanks!

Tom

You can already save the images to the rpi3, and not the controlling machine...then you just see the preview, which in my case does not slow anything down....
I use a Linux Kubuntu laptop to control an rpi3b+ as my server on the pier, and save all images to the rpi on a 64gb USB drive, I still see the fits previews as they take, but they come up at there own speed, it does not affect the sequence, but I do t use one of these newer CMOS cameras with massive files, mines a Mono SXVR H18 Images are about 4mb...

Maybe you refer to the client/local mode which is sustainable with a mono cam and a capture of more or less than 8Mb. But it becomes a mess of time when you are using a DSLR with more than 40Mb. However the availability of such a mode could be a plus while more and more DSLR uses large resolution full frame sensors.

Like you said in your first message, the problem is the speed of the link between your Raspi and your client. So you have to fix this first

The Raspi has a very small antenna and if you try to use the 5Gz mode the problem is even worse. You can greatly improve your link by using a simple USB/WIFI antenna. you can expect a 150 Mb/s link with an effective speed of 90/100 Mb/s. That is enough to download your 40MB image in 4 seconds. Try measuring your effective speed with a tool like iperf. ("iperf -s" on the server side, "iperf -c address" on the client side). If you get less than 80Mb/s transfers, you need to improve this FIRST.

Then you can tweak your setup :
- On the client (EKOS), ask for "native" instead of 'FIT', a raw file is lighter than a fit file. Plus you gain the RAW/FIT conversion time.
- In the INDI profile, ask for MJPEG instead of RAW in the "streaming" field. Your fps jumps to 50 img/s which is enough for focusing in live mode particularly if you use a Bahtinov mask.

I think before modifiing the software, you need to get the best of what is available now first. Then if it's not enough, other solutions may be applied.

- Marc

So are you saying that a USB WiFi dongle is much better than the built in WiFi, as I have the 3b+ with 5ghz, but it’s not great at all...?

Even quicker a mode "SD-Card" only with no local or client saving or previewing would be nice to allow very short poses (planetary/Sun/lucky imaging).

Astronerd :

WIFI can be a very tricky thing... On one side you have the theoretical possibilities and on the other the environment in which your system operates. For example, if you are surrounded by many access points, your system won't be able to aggregate the frequencies to achieve the 40Mhz needed by 802.11n, so you'll be stuck with your basic B/G mode. And if you want to use 802.11ac (5Ghz), depending on your environment again, your link can be VERY fragile.

For 802.11ac mode , you need to have 802.11ac on both computers, the Raspi (only the 3 B+ is capable of ac) and your laptop. The simple 3B doesn't even have a 802.11n mode ( "iw list" gives you HT20 only, no HT20/HT40 ).

So you need to measure the performance of your link FIRST. Once you have measured the problem you can find a solution. Start with "iwconfig" to see the speed of the link. It should at least be 150Mb/s if you want to transfer images from a DSLR or ASI1600/ASI183 (BIG images). Then, try the "iperf " command (see my message above).

If you get a low transfer rate (under 80Mb/s), then you need to find another solution, like a WIFI/USB antenna with a high gain. A simple dongle won't probably do a much better job than the internal WIFI chip.

The best solution I've found so far is a small AP device you plug in an AC outlet, linked to the PI by an ethernet cable. It has a built in HTTP server, so you can easily tweak your connection, set a passphrase , change the ESSID, etc.... On a 3B+, you can expect up to 300Mb/s.

Of course, the major inconvenient is ... Well, you need an AC outlet nearby.

- Marc