An artifact which is generated by maladjustment or circuitry failure in an integrated or stand-alone time base corrector (TBC) can be categorized as a processing artifact. Depending on the type of TBC used, these have a diverse set of manifestations and can include over-enhancement and aggressive noise reduction. If a video signal output to a time base corrector is suddenly lost due to low RF from severe media damage, a head clog or some other incident, the TBC may output noise while the processor attempts to re-lock to the incoming video signal.
In the example below, a TBC was introducing errors through overcorrection. The image on the left is the correct image processed through a properly functioning TBC, while the image on the right shows overcorrection for what would otherwise be minimal skewing at the top, and a line error now appearing along the bottom. During playback, this tape showed a vertically shaky display that wasn’t occurring before the signal was sent through the TBC.
Can it be fixed?
This artifact may be correctable by readjustment or calibration of the TBC. If the TBC cannot process video output due to poor playback signal from the VTR, the media must be treated to improve playback or a different and more effective TBC must be used.