Dropping frames on new laptop with Nvme ssd

[Damo251]

Good evening from Australia Robin,

Thank you for the great software i have been using it for a little while and now i have bought a laptop dedicated for my astrophotography, i will be updating to the pro version to show my support. Thanks again for the hard work.

I have come across and issue on the new laptop that doesn't make sense. And im wondering if you or one of your users have come across it before.

The issue is a huge slowdown on frames when writing to the Nvme ssd in the laptops but does not replicate when writing to an external SSD with one fifth of the write speed.

The laptop is a 2 day old Inspiron 14 running windows 11, fully up to date with an 8 core 16 thread Amd cpu, 16gig of ram and 512gig Nvme ssd. The write speed for the internal drive is anywhere from 1300 Mb/s to 1700 Mb/s on the multiple tests i've done using the provided speed test within Sharpcap.

Using the QHY5iii462c at full frame of 1920x1080 pixels i get the full 135fps while the cpu is only using 16% of its resources, and it is faultless in preview and ran for an hour or so with no issue when ever i wasn't writing to the internal ssd while troubleshooting.

When a capture starts (i use .avi) it will do 3000 to 4000 frames without fault and then start dropping a few frames and by 5000 frames its down to as low as 5 fps, the internal storage is working at around 20% as well until it decides to suddenly give up. Normally i would think cable or full ssd but it has 380gig free of its 512gig and is a brand new item.

To throw a spanner in the works it will write faultlessly (15000 frames +) to an external Samsung T7 SSD with a write speed in the Sharpcap test of "only" 280Mb/s ? I was thinking it was a program within the laptop trying to read all the data produced for malware or something but this still continued when the virus protection program was temporarily stopped.

I have also since found it will write in .ser with no issues to the internal drive which is an equivalent file size to .avi ?

Sorry to bring problems and i hope someone is aware of the issue and has an easy fix.

Kind Regards
Damien K

[admin]

Hi,

it sounds like you have done some fairly thorough troubleshooting already without coming up with any concrete cause

I can make a few suggestions that might help narrow down what is going on, but no obvious answer.

1) Optimise your SSD before testing (Windows disk properties, Tools page). This ensures that any previously used blocks of the drive have been wiped, which means they can be written to quickly. If you have tested a number of times already with large output files you may have written once to most of the drive already, which can mean that to write each new block the SSD has to erase the block first.

2) Watch the 'Memory X of YYY frames in use' status in the bottom status bar in SharpCap. If the number of frames in use starts to rise it means that the writing to disk is not keeping up with the data coming off the camera - when it hits maximum then you will start to get the dropped frames

3) Check that the settings are otherwise identical when capturing SER and AVI. For instance if you capture AVI in RGB mode, but SER in RAW8, the SER file has 3 times less data to write for the same number of frames as the AVI

It's a little tricky to be sure of what happens for the AVI, since SharpCap uses built in Windows components to do the actual AVI writing. This is important from a compatibility point of view to make sure that the AVI files work in pretty much every video player app, but it does mean I have less control than when writing an SER file (which is handled entirely by SharpCap).

It might also be worth seeing if there is a particular size point that the AVI gets to before the slowdown happens - perhaps there is something going on inside the AVI file writing itself that means that it gets slower once the file passes a certain size?

Hope this helps,

Robin

[Damo251]

Hi Robin,

Thanks for the quick and thorough reply.

1. I had optimized the drive with no change before my original post.

2. Frames start dropping to Memory around the 3500 point and are pretty consistent starting at this point but will sometimes last until 6000 before having a complete meltdown.

3. The capture settings are the same for both formats when capturing

4. The size point it starts to have trouble is around the 6-8 gig mark (10000 frame capture is usually 20gig), none of the laptop resources start to struggle before the slowdown. The CPU and storage are doing it easy and can be run in Performance, Balanced or Conserve battery modes with no change to the point of slowdown.

5. Could it be that the AVI writing protocol has change in windows 11? Can i delete the currently used one and install a new/something else or look at rolling back the driver. What program takes care of the writing to file ?

Can it be optimized ?

Thanks for the swift reply again Robin

Kind regards
Damien

[admin]

Hi Damien,

unfortunately the AVI writing is done by Microsoft DirectShow, which is a core Windows component and there isn't a way to replace or update it. SharpCap just tells it what file to write and then throws frames at it - not really much to tinker with either from your side or for me...

I guess I ought to ask the question of why not save in SER format? The file sizes will be similar, but SER is a simpler format, so tends to be more robust - it also has a timestamp for every frame which can be handy. Admitedly you can't watch SER files in media player, but a combination of SERPlayer to view them and PIPP to manipulate/convert them if necessary works well.

cheers,

Robin