What does the “SDI Code Word Violation” error on a digital waveform monitor mean?

What does the “SDI Code Word Violation” error on a digital waveform monitor mean?

An SDI Code Word Violation error occurs when one of the reserved values 0x000 through 0x003 or 0x3FC through 0x3FF is found in the active picture portion of the SDI video stream. These values are prohibited to maintain 8-bit / 10-bit interoperability for legacy systems.