[FFmpeg-trac] #1196(avfilter:closed): drawtext parameter keys "n" and "t" not working

[FFmpeg]

#1196: drawtext parameter keys "n" and "t" not working
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             Reporter:  ad           |                    Owner:
                 Type:  defect       |                   Status:  closed
             Priority:  important    |                Component:  avfilter
              Version:  unspecified  |               Resolution:  invalid
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  1            |
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Changes (by saste):

 * analyzed:  0 => 1
 * status:  new => closed
 * resolution:   => invalid
 * reproduced:  0 => 1


Comment:

 Replying to [ticket:1196 ad]:
 > I tried using drawtext's "n" and "t" parameter keys using the example
 below:
 >
 > ffmpeg -vsync 0 -t 10 -i in)video.mp4 -vf
 drawtext="fontfile=/usr/share/fonts/truetype/ttf-
 dejavu/DejaVuSerif.ttf:text='Text at 5 Looks
 good':fontsize=20:fontcolor=red:x=100:y=100:n=688" out.mp4
 >
 > [drawtext @ 0xa64ca40] Key 'n' not found.
 [...]
 > I get same error with "t" parameter.

 "n" and "t" are not drawtext options, but parameters to be employed in the
 x/y expressions, check the manual.

 > If anyone knows if these parameters work, please give a usage example.

 There are two examples employing the "t" parameter in the manual.

 > Otherwise, do you have any advice on how to achieve objective "1--" and
 "2--" below?
 >
 > 1-- Overlay text 10 seconds into the video.

 There are several ways to achieve this:
 - use the draw expression (undocumented)
 - specify an expression for y, so that the text is rendered *outside* the
 visible area according to a given expression
 - reconfigure the filter through an event (badly undocumented, check the
 ffmpeg-user archive)

 > 2-- Overlay text over video at 1 second intervals into the video.
 >       The text last for 1 second or specified duration.

 Same tricks as above, with a possibly more complicated expression.

 [...]

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1196#comment:1>
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