color_t = sens_frame.color_t[self.computespeed_t_type]
KeyError: ‘frame_device_t’
Probably because two values are not manually added in the registry
Enable Metadata: Metadata contains important timestamp information and needs to be enabled manually. Please refer to:

https://dev.intelrealsense.com/docs/compiling-librealsense-for-windows-guide

Modifying the Windows Registry:
For each interface found (Steps 2 and 3) perform
Using Registry Editing tool such as “regedit” navigate to HKLM\SYSTEM\CurrentControlSet\Control\DeviceClasses{e5323777-f976-4f5b-9b55-b94699c46e44} branch.
Browse into the subdirectory with the name identical to the Device instance path obtained from the previous step
Expand the entry into #GLOBAL -> Device Parameters
Add DWORD 32bit value named MetadataBufferSizeInKB0 with value 5.
Add an additional DWORD 32bit value named MetadataBufferSizeInKB1 with value 5 for RS400 device zero interface ##?##USB#VID_8086&PID… MI_00…

Repeat the previous step for HKLM\SYSTEM\CurrentControlSet\Control\DeviceClasses\{65E8773D-8F56-11D0-A3B9-00A0C9223196} branch