Hi, libfreetype is used to draw text on video stream. http://ffmpeg.org/ffmpeg-filters.html#drawtext-1 There are 3 important syntaxes in the filter of drawtext. fontsize
The font size to be used for drawing text. The default value of fontsize is 16. text_h, th the height of the rendered text text_w, tw the width of the rendered text However, text_h and text_w can only be used in filtergraph description. I want to know the height and width of the rendered text that corresponds to some fondsize, such as fondsize=20. It means, how to calculate the pixel number of rendered text in width and height? Thanks! At 2016-04-26 17:20:13, "Nicolas George" <geo...@nsup.org> wrote: >L'octidi 8 floréal, an CCXXIV, qw a écrit : >> I want to use drawtext filter to put some string on video stream. What is >> the relationship between fontsize and image resolution in drawtext filter? > >The size is the body height of the font in pixels, nothing fancy. > >> If fontsize is set to 20, what is the height and width of rendered text? > >It depends on the font. > >For the height, the rule of thumb is that the body size is the distance >between the top of the tallest glyph (except sometimes accented ones) and >the bottom of the deepest one, typically something like the top of a >parenthesis and the bottom of a p or q. > >For the width, it depends completely, because not all glyphs have the same >width, and you need to take kerning into account too. > >Regards, > >-- > Nicolas George
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