ASI585MC FPS drop when capturing

Calipso232

I have a problem with the ASI585MC camera, in which the FPS stays at full speed for only a dozen or so seconds while capturing the image, and then it drops to about 1-5 FPS. This happens when using SharpCap, FireCapture and ASICap. The camera works on USB 3.0. Do any of you know the reason for this behavior?

w7ay

Calipso232 FPS stays at full speed for only a dozen or so seconds while capturing the image, and then it drops to about 1-5 FPS

My guess is that the USB port becomes the bottleneck when the RAM onboard the camera becomes maxed out. I.e., initially the sensor data only has to be written to the RAM buffer. If the USB bus cannot pull data out fast enough, the RAM will start to fill up (more data arriving than leaving), and the rate becomes the USB data rate.

You can test this conjecture out by reducing the ROI of the sensor data to see if the FPS increases initially, but after about a longer time time, also slows down.

If it is so, I would check to see if the computer is actually seeing the camera as a USB 3 port. A USB 3 port on a ZWO camera will appear on macOS USB Device Tree for example as "Up to 5 Gb/s" when using a USB 3 cable, but as "Up to 480 Mb/s" when using a USB 2 cable.

If you are seeing the USB 3 port of the camera appear as a the slower USB 2 port on the computer, you can try switching to a different cable, or to a different port on the computer. If it still shows up as a USB 2 port, the extra 5 pins in the USB 3 connector on the camera may be faulty. If you are using a USB hub, make sure the hub is a USB 3 hub (baby blue plastic insert instead of black plastic insert).

The way USB switches between USB 2 and USB 3 is that if the extra 5 pins of USB 3 is present, it will use USB 3 full duplex protocol, otherwise, it will revert to using the two data pins of the original 4 pins of the USB connector in half duplex.

Chen

Tech@ZWO

Calipso232 Could you take a video in ASICap to show us the problem?

Thanks.

Calipso232

I checked and the camera is detected as USB 3.0. I am using the original USB 3.0 cable that came with the camera.

Calipso232

asicap-v263-64bit-zwo-asi585mc-395-c-2022-10-31-17-35-04.rar

4MB

Tech@ZWO

Calipso232

Hi I checked the video, but didn't find the problem you said. the fps shows 40+ all through.

Calipso232

=========================== USB Port17 ===========================

Connection Status : 0x01 (Device is connected)
Port Chain : 2-17
Properties : 0x03
IsUserConnectable : yes
PortIsDebugCapable : yes
PortHasMultiCompanions : no
PortConnectorIsTypeC : no
ConnectionIndex : 0x11 (Port 17)
CompanionIndex : 0
CompanionHubSymLnk : USB#ROOT_HUB30#4&393adc3c&0&0#{f18a0e88-c30c-11d0-8815-00a0c906bed8}
CompanionPortNumber : 0x01 (Port 1)
-> CompanionPortChain : 2-1

  ========================== Summary =========================

Vendor ID : 0x03C3 (Unknown Vendor)
Product ID : 0x585B
USB Version : 3.0
Port maximum Speed : SuperSpeed
Device maximum Speed : SuperSpeed
Device Connection Speed : SuperSpeed
Self powered : no
Demanded Current : 512 mA
Used Endpoints : 2

  ======================== USB Device ========================

    +++++++++++++++++ Device Information ++++++++++++++++++

Device Description : ZWO ASI585MC Camera
Device Path 1 : \?\USB#VID_03C3&PID_585B#5&2ad60a6b&0&17#{a5dcbf10-6530-11d2-901f-00c04fb951ed} (GUID_DEVINTERFACE_USB_DEVICE)
Device Path 2 : \?\USB#VID_03C3&PID_585B#5&2ad60a6b&0&17#{c5b27530-3592-4e87-9e99-c2bafd5e5692}
Kernel Name : \Device\USBPDO-3
Device ID : USB\VID_03C3&PID_585B\5&2AD60A6B&0&17
Hardware IDs : USB\VID_03C3&PID_585B&REV_0000 USB\VID_03C3&PID_585B
Driver KeyName : {6bdd1fc6-810f-11d0-bec7-08002be2092f}\0000 (GUID_DEVCLASS_IMAGE)
Driver : \SystemRoot\System32\Drivers\ASICAMUSB3.sys (Version: 1.2.3.3 Date: 2021-12-03)
Driver Inf : C:\WINDOWS\inf\oem93.inf
Legacy BusType : PNPBus
Class : Image
Class GUID : {6bdd1fc6-810f-11d0-bec7-08002be2092f} (GUID_DEVCLASS_IMAGE)
Service : ASICAMUSB3
Enumerator : USB
Location Info : Port#0017.Hub#0002
Location IDs : PCIROOT(0)#PCI(1400)#USBROOT(0)#USB(17), ACPI(SB)#ACPI(PCI0)#ACPI(XHC_)#ACPI(RHUB)#ACPI(SS01)
Container ID : {f620ede3-593b-11ed-9997-806e6f6e6963}
Manufacturer Info : ZWO
Capabilities : 0x84 (Removable, SurpriseRemovalOK)
Status : 0x0180600A (DN_DRIVER_LOADED, DN_STARTED, DN_DISABLEABLE, DN_REMOVABLE, DN_NT_ENUMERATOR, DN_NT_DRIVER)
Problem Code : 0
HcDisableSelectiveSuspend: 0
EnableSelectiveSuspend : 0
SelectiveSuspendEnabled : 0
EnhancedPowerMgmtEnabled : 0
IdleInWorkingState : 0
WakeFromSleepState : 0
Power State : D0 (supported: D0, D3, wake from D0)

    +++++++++++++++++ Registry USB Flags +++++++++++++++++

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\usbflags\03C3585B0000
osvc : REG_BINARY 00 00

    ---------------- Connection Information ---------------

Connection Index : 0x11 (Port 17)
Connection Status : 0x01 (DeviceConnected)
Current Config Value : 0x01 (Configuration 1)
Device Address : 0x08 (8)
Is Hub : 0x00 (no)
Device Bus Speed : 0x02 (High-Speed) -> not true, see below in Connection Information V2
Number Of Open Pipes : 0x01 (1 pipe to data endpoints)
Pipe[0] : EndpointID=1 Direction=IN ScheduleOffset=0 Type=Bulk wMaxPacketSize=1024 bInterval=0
Data (HexDump) : 11 00 00 00 12 01 00 03 00 00 00 09 C3 03 5B 58 ..............[X
00 00 01 02 00 01 01 02 00 08 00 01 00 00 00 01 ................
00 00 00 07 05 81 02 00 04 00 00 00 00 00 ..............

    --------------- Connection Information V2 -------------

Connection Index : 0x11 (17)
Length : 0x10 (16 bytes)
SupportedUsbProtocols : 0x04
Usb110 : 0 (no, port not supports USB 1.1) -> but Companion Port 2-1 does
Usb200 : 0 (no, port not supports USB 2.0) -> but Companion Port 2-1 does
Usb300 : 1 (yes, port supports USB 3.0)
ReservedMBZ : 0x00
Flags : 0x03
DevIsOpAtSsOrHigher : 1 (Device is operating at SuperSpeed or higher)
DevIsSsCapOrHigher : 1 (Device is SuperSpeed capable or higher)
DevIsOpAtSsPlusOrHigher : 0 (Device is not operating at SuperSpeedPlus or higher)
DevIsSsPlusCapOrHigher : 0 (Device is not SuperSpeedPlus capable or higher)
ReservedMBZ : 0x00
Data (HexDump) : 11 00 00 00 10 00 00 00 04 00 00 00 03 00 00 00 ................

---------------------- Device Descriptor ----------------------

bLength : 0x12 (18 bytes)
bDescriptorType : 0x01 (Device Descriptor)
bcdUSB : 0x300 (USB Version 3.0)
bDeviceClass : 0x00 (defined by the interface descriptors)
bDeviceSubClass : 0x00
bDeviceProtocol : 0x00
bMaxPacketSize0 : 0x09 (9 bytes)
idVendor : 0x03C3 (Unknown Vendor)
idProduct : 0x585B
bcdDevice : 0x0000
iManufacturer : 0x01 (String Descriptor 1)
Language 0x0409 : "ZWO"
iProduct : 0x02 (String Descriptor 2)
Language 0x0409 : "ASI585MC"
iSerialNumber : 0x00 (No String Descriptor)
bNumConfigurations : 0x01 (1 Configuration)
Data (HexDump) : 12 01 00 03 00 00 00 09 C3 03 5B 58 00 00 01 02 ..........[X....
00 01 ..

------------------ Configuration Descriptor -------------------

bLength : 0x09 (9 bytes)
bDescriptorType : 0x02 (Configuration Descriptor)
wTotalLength : 0x001F (31 bytes)
bNumInterfaces : 0x01 (1 Interface)
bConfigurationValue : 0x01 (Configuration 1)
iConfiguration : 0x00 (No String Descriptor)
bmAttributes : 0x80
D7: Reserved, set 1 : 0x01
D6: Self Powered : 0x00 (no)
D5: Remote Wakeup : 0x00 (no)
D4..0: Reserved, set 0 : 0x00
MaxPower : 0x40 (128 mA)
Data (HexDump) : 09 02 1F 00 01 01 00 80 40 09 04 00 00 01 FF 00 ........@.......
00 00 07 05 81 02 00 04 00 06 30 0F 00 00 00 ..........0....

    ---------------- Interface Descriptor -----------------

bLength : 0x09 (9 bytes)
bDescriptorType : 0x04 (Interface Descriptor)
bInterfaceNumber : 0x00 (Interface 0)
bAlternateSetting : 0x00
bNumEndpoints : 0x01 (1 Endpoint)
bInterfaceClass : 0xFF (Vendor Specific)
bInterfaceSubClass : 0x00
bInterfaceProtocol : 0x00
iInterface : 0x00 (No String Descriptor)
Data (HexDump) : 09 04 00 00 01 FF 00 00 00 .........

    ----------------- Endpoint Descriptor -----------------

bLength : 0x07 (7 bytes)
bDescriptorType : 0x05 (Endpoint Descriptor)
bEndpointAddress : 0x81 (Direction=IN EndpointID=1)
bmAttributes : 0x02 (TransferType=Bulk)
wMaxPacketSize : 0x0400 (max 1024 bytes)
bInterval : 0x00 (never NAKs)
Data (HexDump) : 07 05 81 02 00 04 00 .......

    ------ SuperSpeed Endpoint Companion Descriptor -------

bLength : 0x06 (6 bytes)
bDescriptorType : 0x30 (SuperSpeed Endpoint Companion Descriptor)
bMaxBurst : 0x0F (up to 16 packets per burst)
bmAttributes : 0x00 (The bulk endpoint does not define streams)
wBytesPerInterval : 0x0000
Data (HexDump) : 06 30 0F 00 00 00 .0....

  ---------- Binary Object Store (BOS) Descriptor -----------

bLength : 0x05 (5 bytes)
bDescriptorType : 0x0F (Binary Object Store)
wTotalLength : 0x0016 (22 bytes)
bNumDeviceCaps : 0x02
Data (HexDump) : 05 0F 16 00 02 .....

    ------------- USB 2.0 Extension Descriptor ------------

bLength : 0x07 (7 bytes)
bDescriptorType : 0x10 (Device Capability Descriptor)
bDevCapabilityType : 0x02 (USB 2.0 Extension)
bmAttributes : 0x02
LPMCapable : 1 (Link Power Management protocol is supported)
BESLAndAlternateHIRD : 0 (BESL & Alternate HIRD definitions are not supported)
BaselineBESLValid : 0 (not valid)
DeepBESLValid : 0 (not valid)
BaselineBESL : 0
DeepBESL : 0
Data (HexDump) : 07 10 02 02 00 00 00 .......

    ----- SuperSpeed USB Device Capability Descriptor -----

bLength : 0x0A (10 bytes)
bDescriptorType : 0x10 (Device Capability Descriptor)
bDevCapabilityType : 0x03 (SuperSpeed USB Device Capability)
bmAttributes : 0x00
Bit 0 Reserved : 0x00
Bit 1 LTM Capable : 0x00 (no)
Bit 7:2 Reserved : 0x00
wSpeedsSupported : 0x0E (Full-Speed, High-Speed, SuperSpeed)
bFunctionalitySupport : 0x03 (lowest speed with all the functionality is 'SuperSpeed')
bU1DevExitLat : 0x0A (less than 10 µs)
wU2DevExitLat : 0x07FF (less than 2047 µs)
Data (HexDump) : 0A 10 03 00 0E 00 03 0A FF 07 ..........

  -------------------- String Descriptors -------------------
         ------ String Descriptor 0 ------

bLength : 0x04 (4 bytes)
bDescriptorType : 0x03 (String Descriptor)
Language ID[0] : 0x0409 (English - United States)
Data (HexDump) : 04 03 09 04 ....
------ String Descriptor 1 ------
bLength : 0x08 (8 bytes)
bDescriptorType : 0x03 (String Descriptor)
Language 0x0409 : "ZWO"
Data (HexDump) : 08 03 5A 00 57 00 4F 00 ..Z.W.O.
------ String Descriptor 2 ------
bLength : 0x1C (28 bytes)
bDescriptorType : 0x03 (String Descriptor)
Language 0x0409 : "ASI585MC°°°°°" !ERROR contains 5 NULL characters
Data (HexDump) : 1C 03 41 00 53 00 49 00 35 00 38 00 35 00 4D 00 ..A.S.I.5.8.5.M.
43 00 00 00 00 00 00 00 00 00 00 00 C...........

This is the raport from the USB Device Tree Viewer

Calipso232

Yes, but this is only the preview FPS (by the way, this should be fixed in ASICap because the actual FPS is probably more important). As you can see in the video, at some point the buffer overflows and from that point on most frames are lost.

Calipso232

This is more clearly seen in SharpCap.

sharpcap-v409357-64-bit-zwo-asi585mc-2e304c041c010900-via-usb3-c-users-mitas-onedrive-desktop-sharpcap-captures-2022-11-01-08-27-14.rar

3MB

w7ay

Calipso232 This is more clearly seen in SharpCap.

Definitely slows down from over 40 FPS to less than 5 FPS after about the 27 second mark -- around the duration of 230 MB of data (close to 256 MB!).

I am curious, are you writing to a solid state drive (SSD) on the computer? With RAW8, you would be recording at 8.3 MBytes per frame. A slow laptop HDD for example would only typically write at 30 MBytes/sec or so, and that would cause you to slow down to less than 5 FPS once its cache is overrun.

The interesting thing is that the cache memory on the ASI585 is 256 MBytes, but many HDD also have 256 MBytes of cache. That is about the point where your capture abruptly slows down.

The curious thing is that your capture does not suddenly switch speed, but has a transition period when the FPS slowly creeps down -- much like what you'd expect from a caching failure.

You might experiment with using RAW16 to see if it takes a shorter time before the FPS slows down. And if you have lots of RAM in the computer, try to map the memory as a RAM drive, unless you are already using an SSD instead of an HDD.

Chen

Calipso232

w7ay OKAY. I found where the problem was. I did a lot of tests on different computers and it turned out that the SSD was the bottleneck. When I checked its performance while capturing a video, it only maintains full speed for a few seconds and then the transfer rate drops to around 60MB/s. The interesting thing is that it is an MVMe PCI-e 3.0 x 4 SSD. After replacing the drive with a SAMSUNG 980 1TB NVMe PCI-e 3.0 x 4, the camera captures videos with maximum FPS on all possible configurations. Thank you w7ay for helping me and guiding me to a solution.

w7ay

Calipso232 SAMSUNG 980 1TB NVMe PCI-e

Yeah, that one should be quite good. Good to see that you have solved your problem.

I have a couple of Samsung 970 (also NVMe) on my Mac Studio and get over 1.25 GBytes/second write speeds on just the 970.

Chen