Alkeria NECTA Series - Packet Size for Isochronous Endpoint

8. Capturing Images 101
8.9.4 Packet size for isochronous endpoint
The packet size parameter controls the maximum amount of data the device can send during a micro-
frame. Not all values are permitted: the boundaries for the allowed packet size are adjusted by the cam-
era according to the operating conditions; they depend on several parameters (ROI, ADC resolution, pixel
format, etc.) inuencing both acquisition speed and size of data to be sent. Refer to Section 8.9.4.1 for
more details about how the required bandwidth can be estimated.
Note
When the camera automatically recalculates the packet size range, it also sets
the packet size to the current maximum allowable value.
Note
The maximum allowed value for the packet size is the optimum value, be-
yond which there is no frame rate increase. Setting a packet size larger than
MaxPacketSize generates an exception.
Note
The amount of bandwidth available on each interface can be restricted by the
SetBandwidthLimits method, refer to Section 8.9.2.
Before starting live image acquisition, based on the current bandwidth limits and current packet size, API
selects the lowest available alt-interface providing the required bandwidth.
Note
Selecting a bandwidth limit stricter than the minimum required bandwidth
makes acquisition start impossible. An exception is thrown to signal this er-
ror condition.
The following code sets the PacketSize to 8192 B per micro-frame (8 KiB per micro-frame), after check-
ing it does not exceed the maximum allowed packet size.
Example Code 8.13 | Set PacketSize property
device.PacketSize = Math.Min(device.MaxPacketSize, 8);