[FFmpeg-user] Weird results with drawtext

[Cecil Westerhof]

Cecil Westerhof via ffmpeg-user <ffmpeg-user at ffmpeg.org> writes:

> I have several of the following (simplified):
>     drawtext=
>        enable     = 'between(t, 105, 115)':
>        text       = 'speaker':
>        y          = main_h - (text_h * 4),
>     drawtext=
>        enable     = 'between(t, 105, 115)':
>        text       = 'subject':
>        y          = main_h - (text_h * 2.2),
>
> I have been carefully tweaking to get them on the correct place.
> But when I was satisfied and generated all eight places where I wanted
> to have them the placement of the speaker and subject text is on
> different heights. Sometimes one or the other is different, sometimes
> both and sometimes they are the same.
>
> Is this a bug, or am I doing something wrong?

As Michael Koch said:
    The content of the variable "text_h" depends on which characters
    you are printing.

So I changed:
    drawtext=
       enable     = 'between(t, 105, 115)':
       text       = 'speaker':
       y          = main_h - (text_h * 4),
    drawtext=
       enable     = 'between(t, 105, 115)':
       text       = 'subject':
       y          = main_h - (text_h * 2.2),

to:
    drawtext=
       enable     = 'between(t, 105, 115)':
       text       = 'speaker':
       y          = main_h - 200,
    drawtext=
       enable     = 'between(t, 105, 115)':
       text       = 'subject':
       y          = main_h - 140,

That gives satisfactory results. The only problem is when the font
size changes. Then I have to remember I need to change these two
values also. But I do not expect that to happen often, so I can live
with that.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof