[FFmpeg-trac] #2769(FFmpeg:new): drawtext: draw expression on a range on frames

FFmpeg trac at avcodec.org
Wed Jul 10 15:16:23 CEST 2013


#2769: drawtext: draw expression on a range on frames
-------------------------------------+-------------------------------------
             Reporter:  Charlie      |                     Type:
               Status:  new          |  enhancement
            Component:  FFmpeg       |                 Priority:  normal
             Keywords:  drawtext     |                  Version:  0.8.14
  fraw expression range frame        |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 Hi, drawtext option has a 'draw' expression that specifies if the text
 should be drawn.
 http://www.ffmpeg.org/ffmpeg-filters.html#drawtext-1

 I figured out we could use the following expressions to write on, before,
 or after a specific frame: :draw='eq(n,42)', :draw='lt(n,42)',
 :draw='gt(n,42)'

 Do you know how to combine two expressions to write text, for instance, on
 every frame between frames 10 and 42 ?
 I couldn't find doc or examples for combining expressions, and the
 following don't work:
 :draw='gt(n,10)&&lt(n,42)' -> crash
 :draw='gt(n,10);lt(n,42)' -> only applies second expression
 :draw='gt(n,10)':draw='lt(n,42)' -> only applies second expression

 Thanks in advance

 How to reproduce:
 {{{
 % ffmpeg -i test.mov -vf
 "[in]drawtext=fontsize=40:fontcolor=White:fontfile='/usr/share/fonts/truetype
 /ttf-
 dejavu/DejaVuSans.ttf':draw='gt(n,10)':draw='lt(n,42)':text='test':x=50:y=35"
 -vframes 60 -qscale 0 -preset medium -vcodec libx264 -pix_fmt yuv420p
 -strict experimental -y test.mp4
 ffmpeg version 0.8.6-4:0.8.6-0ubuntu0.12.04.1, Copyright (c) 2000-2013 the
 Libav developers
   built on Apr  2 2013 17:02:36 with gcc 4.6.3
 }}}

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2769>
FFmpeg <http://ffmpeg.org>
FFmpeg issue tracker


More information about the FFmpeg-trac mailing list