Several video applications need to acquire a video stream and to display it on an LCD panel or similar device. In some cases it is required that the latency measured between source stream and stream feeding LCD panel is within a specified time (often expressed in terms of fields).

http://processors.wiki.ti.com/index.php/Latency_Measurement_on_Capture_Encode_Decode_Display_Demo. Method suggested by TI is completely software-based. Since Linux is not an RTOS, the intrinsic error of such method might not be tolerable where the application has hard real-time latency requirements. Thus a hardware-based approach has been implemented to build ad hoc testbed as described in the following section.