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 is45
. - 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 thanthr_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 thanthr_b
.
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'