A few days ago, my trusted Dell laptop died. I now own a new Acer with an Intel Core i5 processor, 16 GB of RAM, and a 1TB SSD. I use it for Spectroheliograph work. Yesterday was a clear sky day after many weeks, and I tried some capturing. It did not work. SharpCap (with a Pro license) was dropping too many frames, resulting in a very jerky video. Completely useless. My captures are with an ROI of 2312 x 112 pixels and done at a high frame speed, like 238 FPS yesterday. I never had this problem with my old Dell.
Any idea what is going wrong?
Thanks
PS> I made a screen capture video in MP4 format, but I believe MP4 format is permitted as an attachment here.
What could be going wrong?
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Re: What could be going wrong?
Hi,
in situations like this, the first thing to do is to watch the frames dropped number at the bottom left. If it goes up all the time (even when just watching the image) then the problem is to do with getting frame data from the camera to the computer. On the other hand, if it only goes up while capturing (or much more while capturing) then it is to do with saving the data to file.
I suspect that it will be saving the data to file - that's usually the cause for this sort of problem. Based on that assumption, things to check are
* That you are saving to SER file, not accidentally saving to a still file format like PNG or FITS
* That you have plenty of space spare on your SSD
* If you are saving to an external drive that it is connected at USB3 speeds
* That the SSD/Drive that you are saving too has been recently optimized/defragmented.
It's also worth noting that if you find things work properly for a while then slow down after capturing for a bit, this can happen when your SSD has a relatively small area set aside for 'fast writing'. Sometimes this area can be only 5 or 10% of the full drive capacity, so if you have a 500Gb drive you may find the first 50Gb of captures work nicely then it will start dropping lots of frames. Leave the PC running for an hour or so and it will be OK again as the SSD has moved the data from the 'fast writing' to a normal speed area in the background.
cheers,
Robin
in situations like this, the first thing to do is to watch the frames dropped number at the bottom left. If it goes up all the time (even when just watching the image) then the problem is to do with getting frame data from the camera to the computer. On the other hand, if it only goes up while capturing (or much more while capturing) then it is to do with saving the data to file.
I suspect that it will be saving the data to file - that's usually the cause for this sort of problem. Based on that assumption, things to check are
* That you are saving to SER file, not accidentally saving to a still file format like PNG or FITS
* That you have plenty of space spare on your SSD
* If you are saving to an external drive that it is connected at USB3 speeds
* That the SSD/Drive that you are saving too has been recently optimized/defragmented.
It's also worth noting that if you find things work properly for a while then slow down after capturing for a bit, this can happen when your SSD has a relatively small area set aside for 'fast writing'. Sometimes this area can be only 5 or 10% of the full drive capacity, so if you have a 500Gb drive you may find the first 50Gb of captures work nicely then it will start dropping lots of frames. Leave the PC running for an hour or so and it will be OK again as the SSD has moved the data from the 'fast writing' to a normal speed area in the background.
cheers,
Robin
Re: What could be going wrong?
Hi Robin,
Thank you for the fast reply. Yes, I was doing it as a 16-bit SER video, on a relatively empty internal SSD drive (like 850 GB free, out of 1TB), and I believe the SSD drive is not fragmented because it is a brand new laptop.
The only thing I did was to create the "ShapCap Captures" folder on my Desktop and delink it from backup on OneDrive. My captures run into several hundred GB in size, and OneDrive always creates issues for me. Once I do the processing, I delete the SER files. Could the "delinking" from OneDrive have caused the dropped frames?
With my old Dell laptop, I had entirely opted out of the OneDrive backup feature, and I regret it because it left me with no backup for all my personal data.
Thanks
Thank you for the fast reply. Yes, I was doing it as a 16-bit SER video, on a relatively empty internal SSD drive (like 850 GB free, out of 1TB), and I believe the SSD drive is not fragmented because it is a brand new laptop.
The only thing I did was to create the "ShapCap Captures" folder on my Desktop and delink it from backup on OneDrive. My captures run into several hundred GB in size, and OneDrive always creates issues for me. Once I do the processing, I delete the SER files. Could the "delinking" from OneDrive have caused the dropped frames?
With my old Dell laptop, I had entirely opted out of the OneDrive backup feature, and I regret it because it left me with no backup for all my personal data.
Thanks
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Re: What could be going wrong?
Hi Prasad,
I don't think OneDrive will have anything to do with it - my understanding is that it will try to back up files later rather than doing it while they are being written, so it shouldn't interfere with SER file writing.
A couple of things you can do -
* think about whether antivirus/security software could be causing this - maybe it is tring to scan SER files as they are written? A crazy thing to do, but some antivirus software is pretty crazy. I usually stick with Microsoft Defender or whatever it's called these days as it is fairly unintrusive. If you are using other software, maybe exclude the SharpCap Captures folder from scanning?
* Run the disk write speed test in SharpCap's disk speed test (found near the top right of the filename settings). That gives you a disk write speed, although I suspect that for modern PCs the fact that it only writes about 6Gb may mean that it could all get cached in RAM by Windows. Anyway, see what the speed you get reported there - a good NVMe SSD should give 3000Mb/s or more if it is working well.
cheers,
Robin
I don't think OneDrive will have anything to do with it - my understanding is that it will try to back up files later rather than doing it while they are being written, so it shouldn't interfere with SER file writing.
A couple of things you can do -
* think about whether antivirus/security software could be causing this - maybe it is tring to scan SER files as they are written? A crazy thing to do, but some antivirus software is pretty crazy. I usually stick with Microsoft Defender or whatever it's called these days as it is fairly unintrusive. If you are using other software, maybe exclude the SharpCap Captures folder from scanning?
* Run the disk write speed test in SharpCap's disk speed test (found near the top right of the filename settings). That gives you a disk write speed, although I suspect that for modern PCs the fact that it only writes about 6Gb may mean that it could all get cached in RAM by Windows. Anyway, see what the speed you get reported there - a good NVMe SSD should give 3000Mb/s or more if it is working well.
cheers,
Robin
Re: What could be going wrong?
Hi Robin,
I was using Windows Defender on my old laptop. The new laptop came with McAfee AV for free. I disabled the McAfee AV and ran the speed test. I also disconnected the WiFi (to disconnect OneDrive) and tried. I am getting speeds like 1200 to 1800 Mb/s. Disconnecting McAfee or OneDrive did not make any difference. I never experienced dropped frames on my old laptop, which died, though I didn't test disk write speed. It was never a problem. It was also with an Intel i5 processor, while this new one is a Core Ultra i5, supposed to be better? I am not sure anymore. Luckily, I have the option to return it for a full refund. I will buy another one with a faster processor, hopefully a better one.
Thanks again for your support.
Prasad
I was using Windows Defender on my old laptop. The new laptop came with McAfee AV for free. I disabled the McAfee AV and ran the speed test. I also disconnected the WiFi (to disconnect OneDrive) and tried. I am getting speeds like 1200 to 1800 Mb/s. Disconnecting McAfee or OneDrive did not make any difference. I never experienced dropped frames on my old laptop, which died, though I didn't test disk write speed. It was never a problem. It was also with an Intel i5 processor, while this new one is a Core Ultra i5, supposed to be better? I am not sure anymore. Luckily, I have the option to return it for a full refund. I will buy another one with a faster processor, hopefully a better one.
Thanks again for your support.
Prasad
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admin
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Re: What could be going wrong?
Hi Prasad,
those disk write speeds sound fine - putting in your ROI values and frame rate, you would only need to write about 60Mb/sec at 8 bit or 120Mb/sec at 16 bit - far below the disk write speeds. Additionally, the CPU should be plenty fast enough for that sort of capture.
Can you just confirm that you are *only* seeing the dropped frames when capturing - if you see them also when just watching the image from the camera and not actively capturing then the disk write performance is not going to be the issue - it will probably be some USB related issue in that case.
thanks,
Robin
those disk write speeds sound fine - putting in your ROI values and frame rate, you would only need to write about 60Mb/sec at 8 bit or 120Mb/sec at 16 bit - far below the disk write speeds. Additionally, the CPU should be plenty fast enough for that sort of capture.
Can you just confirm that you are *only* seeing the dropped frames when capturing - if you see them also when just watching the image from the camera and not actively capturing then the disk write performance is not going to be the issue - it will probably be some USB related issue in that case.
thanks,
Robin
Re: What could be going wrong?
Hello Robin,
That is so relieving to read that the speed I am getting is good enough for my application. I just tried it indoors now. When I capture using the Acer laptop camera, 0 frames got dropped. It seems to happen only when I connect an external camera. I tried switching cameras, USB ports, and also using different USB cables. Only a few frames were dropped during capture, like 100 frames out of over 11k frames. I think 100 frames out of 11k is not bad. Strangely, in a couple of attempts, 0 frames got dropped. Switching cameras, USB ports, or USB cables made no significant difference.
I will wait for a clear sky day and try it properly to see how it works.
Thank you for your wonderful support. I really appreciate it.
Prasad
That is so relieving to read that the speed I am getting is good enough for my application. I just tried it indoors now. When I capture using the Acer laptop camera, 0 frames got dropped. It seems to happen only when I connect an external camera. I tried switching cameras, USB ports, and also using different USB cables. Only a few frames were dropped during capture, like 100 frames out of over 11k frames. I think 100 frames out of 11k is not bad. Strangely, in a couple of attempts, 0 frames got dropped. Switching cameras, USB ports, or USB cables made no significant difference.
I will wait for a clear sky day and try it properly to see how it works.
Thank you for your wonderful support. I really appreciate it.
Prasad
Re: What could be going wrong?
Prasad
For testing purposes, I have a https://www.amazon.co.uk/RNXRZANK-Fixed ... B0GDYDG7Q9 , cost ~£10.
The CS mount lens screws into my camera. This way I can carry out daylight testing from in the house, by focusing on a tree, TV aerial or mobile mast etc. A more comfortable way to resolve problems and saves wasting clear skies.
Dave
For testing purposes, I have a https://www.amazon.co.uk/RNXRZANK-Fixed ... B0GDYDG7Q9 , cost ~£10.
The CS mount lens screws into my camera. This way I can carry out daylight testing from in the house, by focusing on a tree, TV aerial or mobile mast etc. A more comfortable way to resolve problems and saves wasting clear skies.
Dave
Re: What could be going wrong?
Hi Robin
My problem was resolved. It was the Acer laptop. Something was wrong with it, I guess. Well, I returned it and bought a Dell, with an Intel Core Ultra i9 processor and 32 GB memory, etc. I no longer see so many dropped frames, even while the capture rate is like 400 fps. Of course, I p[aid twice as much.
Thanks for all the support,
-Prasad
My problem was resolved. It was the Acer laptop. Something was wrong with it, I guess. Well, I returned it and bought a Dell, with an Intel Core Ultra i9 processor and 32 GB memory, etc. I no longer see so many dropped frames, even while the capture rate is like 400 fps. Of course, I p[aid twice as much.
Thanks for all the support,
-Prasad