Frequently Asked Question

The stream bandwidth of the Chameleon may be limited because of several factors:

1. PCIe bandwidth limitations - a computer PCIe slot may support one speed according to specification, but actual PCIe slot speed may vary due to the motherboard, proximity to CPU or other peripherals connected on the PCIe bus.
To resolve this issue, the card should be moved to a more powerful PCIe slot.

2. Selected image dimension, PixelFormat, protocol speed and the number of connected cables - all these factors should be taken into account when calculating the theoretical bandwidth.
Image dimensions influence the number of transmitted pixels.
Image PixelFormat determines the number of bytes transmitted for each pixel - while data on the protocol is packed, the data on PCIe is always 2 bytes for 10/12/14/16bit pixel format and 1 byte for 8bit pixel format.
Protocol speed and number of cables define the maximum number of bytes that can be transmitted on the cable including protocol headers etc.The actual raw data which can be transmitted is in fact ~80% of the theoretical expected protocol speed.

3. When working in queued buffers management mode, the application fails to return buffers to the acquisition library on time thus hardware doesn't have any buffers to generate the next frame. To overcome this issue, the number of buffers allocated by the software should be increased as shown in the image below. *Please note that the pattern type source image would start moving. A file as the video source can be used in case a still image is needed.

4. Additional payload on PCIe slot - if there are additional peripheral devices connected on the shared PCIe bus that might affect the maximum bandwidth on that PCIe bus and reduce the overall stream bandwidth of the Chameleon.
In case multiple camera commands are sent over the communication cable, while the stream is in progress, this might also reduce the stream payload size on the cable.