ToupTek usage with SharpCap

[ubergarm]

Thanks for the update on the 'advanced' DirectShow driver!

## tl;dr;
DirectShow driver currently seems to work better than ASCOM for everything except possibly Binning.

## Background
I had first light on my new OGMA AP26MC Monochrome IMX571 sensor with SharpCap Pro Beta 4.1.11069.0 02 October 2023 build last night imaging good old Andromeda Galaxy. I was shooting luminance in windy conditions and poor seeing with no guiding so wanted short subs. I use Live Stacking with the *amazing* "poor man's" dithering and drift correction features to keep my rig lean. I save all the frames and stack thousands of short subs offline in Siril the next morning on my Linux desktop for final processing.

## Issues with ASCOM driver
The smart histogram suggested about 3 seconds in my Bortle ~5.4 site. However, the ASCOM driver introduces almost 1 second delay in-between each frame captured. You can even see the timer in the bottom right corner go to negative after every frame. This latency was present regardless of the driver settings or exposure duration. I tried multiple known-good USB cables with no change. Using 2x2 binning reduced the issue somewhat, but not completely. So probably the ASCOM driver has to copy the data somehow with an implementation that wastes valuable photon grabbing time. As such I used longer 5 second subs to reduce the loss. My file timestamps show me imaging for 3 hours 6 minutes and 36 seconds wall clock duration. There are only 1779 sub files for a total integration of 2 hours 28 minutes 15 seconds. So roughly 20% of time lost due to ASCOM driver inter-frame-latency (assuming minimal time spent dithering and settling).

## Success with DirectShow driver
This morning I found this thread and did some tests. I installed the latest DirectShow OGMA "AP26MC" driver and for my purposes it seems to do everything better than the "ASCOM OGMAVision Camera" driver.

1. It captures at the expected published framerates for the given settings with no wasted latency between frames.
1. It captures at the correct published resolution MONO16@6224x4168 instead of some odd MONO16@6216x4152
1. The extra functions are integrated in SharpCap and seem to all work (Cooler works great, can even change the dew heater level too, black level offset easier to tweak).

The only issue I've found is that the Sensor Analysis crashes towards the last steps when it starts changing the Binning settings. I repro'd the bug and filed the 2x reports already.

## Conclusion
I'm soooo happy to find that the latest DirectShow driver will let me efficiently shoot short subs for Live Stacking!!! It feels almost as good as native SDK driver support. My only gripes with it are that the 'old' DirectShow driver seems to still appear as an option in the Camera menu with the exact same name as new new good one. I tried it and it only had RGB32 which immediately looked wrong with my mono sensor. I'm not worried about Binning except to complete a valid Sensor Analysis with this driver. I can't tell for sure if it is indeed USB 3.0 or not, but the framerate is fast enough for "Lucky DSO" and I have a different planetary camera for the real fast stuff anyway.

Cheers and clear skies!
-John Leimgruber "ubergarm"

## Screenshot Attachments
* DirectShow OGMA "AP26MC" driver working great maxing out published FPS on low noise mode.
* DirectShow "ASCOM" driver set to 10s subs showing slower than expected FPS.
* SharpCap Camera Menu showing two identically named DirectShow drivers and which one is "good".

[admin]

Hi,

good to hear that the advanced directshow support is working well for you (if not quite flawlessly).

For the double entry, it might be that you have two versions of the DirectShow installed somehow (Touptek + OGMA?) Maybe try uninstalling all and reinstalling latest.

I have seen issues with the sensor analysis crashing - you can turn off the binning test at the end (there's a checkbox when you start the analysis). That's probably easiest for now, as the interaction between the resolution of the camera and the binning/ROI settings is particularly hard to handle in the advanced DirectShow driver approach. I'm reluctant to make changes and possibly break other places for the sensor analysis bug.

cheers,

Robin

[ubergarm]

Thanks again, Robin!

Disabling binning test allowed me to successfully complete sensor analysis with the advanced DirectShow driver! See attached results below for both LCG and HCG in "Low Noise" mode. Anecdotally the results appear to now more closely match the published ZWO ASI2600MM values than when using the ASCOM driver.

Last question, does the Smart Histogram "Brain" button automatically use the correct saved sensor analysis based on the selected "Read Mode"? If there is just a single saved analysis per camera, I'll re-run in HCG mode as I'll be using that mostly.

Clear skies!
-John "ubergarm"

[admin]

Hi John,

yes, those values look about right - of course ZWO auto-switches from LCG to HCG at about 3x gain (100 gain in their numbers, 300 in the values used by ToupTek).

SharpCap does track the sensor data separately for the different read modes, so once you have run the analysis on both modes, it should pick the right one automatically when using the smart histogram tool.

cheers,

Robin

[soundfan]

Hello everyone,

I almost forgot about this thread and I'm happy I found it again. Been using the unbranded Touptek 2600C for a while now with ASCOM driver only. Faced the same issues with the latency between the frames and some other issues like cooling often needs to be switched on and off a couple of times before it takes the new set value and starts cooling properly. Also changing exposure or gain repeatedly resulted in a 60 seconds response delay of the camera before new frame can be caught.

Now I learned that there is a much better working DirectShow driver available. Can someone point me to the download source? The drivers on the Touptek homepage are from 2021...

Many thanks for all your help in advance!

CS
Mike

[ubergarm]

@soundfan -

Thanks for confirming your similar experiences with the ASCOM driver. I'm using the OGMA version of the camera with the DirectShow drivers here: https://getogma.com/download . Not sure it would work the same on your model or not but might be worth a try. TBH I'm not sure how old this driver is relative to the one you found either.

Unfortunately, after more testing in the field, I was still having issues with the DirectShow driver. While it seemed to work well for short exposure subs (e.g. < 5 to 15 seconds), I hit issues doing narrowband imaging with 180 second subs. After an hour of Live Stacking with PHD2 guiding dithering after every frame, I noticed the output folder did not have the number of subs expected. I started paying closer attention and it seems like the pattern was roughly:

1. Live Stacking starts and first frame comes out fine after 180 seconds.
2. Dithering happens and frame rate drops to 2 second subs and settles after 5 to 10 seconds as configured.
3. New frame starts but goes for 200 seconds with the counter in the bottom right saying "-20" seconds.
4. No frame stacks and the counter starts over. I assume Sharp Cap is hard-coded to give up after 20 seconds and start a new sub.
5. Next frame counts up to around 150 seconds then suddenly it says a frame is ready and stacks it then starts the counter over.

After realizing I was losing maybe 40% of my data I stopped live stacking and tried to setup the most basic Deep Sky Sequence. However the counter went negative -20 seconds then threw an error message and canceled the sequence. I couldn't figure it out in the field so just went back to LiveStacking and ate the loss to at least get some data.

After I got home, I setup to shoot my 180s darks. No problem at all, each one rolled right off the sensor and immediately saved and the frame counter never went negative.

My guess is that something with how the Sharp Cap adjusts the frame rate down during dithering then back up again might be causing a subtle issue. Especially with how @soundfan mentions changing settings (on ASCOM driver, I know apples to oranges...) causes hiccups.

So tl;dr; is probably stick with ASCOM for imaging longer duration subs as the intermittent loss is not as bad, and use DirectShow for short subs where that loss is more significant proportion of the time.

Sorry I don't have better news!

[admin]

Hi folks,

I think the diagnosis of the timed out frame being related to the exposure change is probably correct - SharpCap will timeout after the expected exposure (plus an allowance of up to about 20s) has passed, as trying again is better than waiting for ever. From the sound of the next frame finishing early, I wonder if somehow the camera is finishing the first 180s frame but SharpCap isn't receiving it, then the second frame starts while SharpCap is still waiting for the first, resulting in the second appearing early.

Anyway, hopefully all of this will be history soon, as I am expecting to have full SDK support for ToupTek cameras available by the end of this month.

cheers,

Robin

[mjcanelson]

Fantastic! I'm regularly using my IMX571 now. A couple questions:
Are you planning on making the on camera binning available as an
option? Also, I can't find the control for HGC/LGC. What's the default,
or should I set it with the ASCOM driver?

Thanks again for getting these cameras running.

[admin]

Hi,

not sure if you are on the very latest SharpCap version yet, but the latest updates do now have pretty much full ToupTek support directly via the SDK. I may remove the 'Advanced DirectShow' code in a month or two.

The new ToupTek support in SharpCap should give you access to binning. I have done my best to hide LCG/HCG from the user by merging it into the gain setting of the camera - this is the approach followed by lots of other brands like ZWO, PlayerOne, etc, and I think the consistency is helpful. SharpCap will automatically switch into the HCG mode when the gain setting is high enough to allow it - 300 gain for the IMX571 sensor.

cheers,

Robin

[mjcanelson]

Thanks for the explanation on HGC/LGC. Knowing where the threshold is helps quite a bit.
I believe the chip does support 2x2 and 3x3 on chip binning. Is that supported or is it post
delivery binning?

Thanks again for the work on getting the support native.

Cheers,
Matt