readvitc

Read vertical interval timecode (VITC) information from the top lines of a video frame.

The filter adds frame metadata key lavfi.readvitc.tc_str with the timecode value, if a valid timecode has been detected. Further metadata key lavfi.readvitc.found is set to 0/1 depending on whether timecode data has been found or not.

This filter accepts the following options:

'scan_max'

Set the maximum number of lines to scan for VITC data. If the value is set to -1 the full video frame is scanned. Default is 45.

'thr_b'

Set the luma threshold for black. Accepts float numbers in the range [0.0,1.0], default value is 0.2. The value must be equal or less than thr_w.

'thr_w'

Set the luma threshold for white. Accepts float numbers in the range [0.0,1.0], default value is 0.6. The value must be equal or greater than thr_b.

Command line examples

• Detect and draw VITC data onto the video frame; if no valid VITC is detected, draw --:--:--:-- as a placeholder:

  ffmpeg -i input.avi -filter:v 'readvitc,drawtext=fontfile=FreeMono.ttf:text=%{metadata\\:lavfi.readvitc.tc_str\\:--\\\\\\:--\\\\\\:--\\\\\\:--}:x=(w-tw)/2:y=400-ascent'