Transport Data Packing¶

This feature enables bit packing on transport data layer - USB3, USB 2.0, PCIe, Thunderbolt.
Transport data packing removes unused zero bits which might increase the maximum frame rate.

Cameras supporting this feature¶

List of camera families supporting the Transport Data Packing:

camera families

xiMU

xiQ except of models: MQ013xG-E2

xiC

xiB

xiT

xiX

Example: Without data packing each 10 bit pixel is transported in two bytes (16bits).
When Transport Data Packing is enabled the bits from multiple pixels are grouped in multiple bytes.
On xiQ cameras: 16 pixels x 10 bits = 160 bits are grouped in 20 bytes.
This uses only 60% of the unpacked data amount (160 bits instead of 256bits).

Example of Frame Rate Increase with enabled packing¶

Camera model	MQ022xG-CM	MQ022XG-CM
Packing	enabled	disabled
Measured FPS	133.9	84.6

Camera model	MQ042xG-CM	MQ042XG-CM
Packing	enabled	disabled
Measured FPS	71.4	45.1

• Tested using XI_RAW16 image format (16bit) at full resolution
• Tested on PC
  • CPU: Intel Core i5-3570K 3.40Ghz
  • USB3 controller: Z77

Feature parameters¶

xiApi parameters¶

Feature related parameters

XI_PRM_IMAGE_DATA_FORMAT = XI_RAW16

XI_PRM_OUTPUT_DATA_BIT_DEPTH = 10

XI_PRM_OUTPUT_DATA_PACKING = 1

NOTE: Order of parameters setting is mandatory

Sample code¶

// set trigger source
// set API image data format
xiSetParamInt(h,XI_PRM_IMAGE_DATA_FORMAT, XI_RAW16);
// set 10 bit transport data width
xiSetParamInt(h,XI_PRM_OUTPUT_DATA_BIT_DEPTH, 10);
// enable packing
xiSetParamInt(h,XI_PRM_OUTPUT_DATA_PACKING, XI_ON);
// start acquisition
xiStartAcquisition(h);