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• build ffmpeg with my static lib "undefined reference to" [duplicate]

  7 septembre 2020, par Vassago

  exec

  


  nvcc xtest.cu -c
ar rcs libxtest.a xtest.o


  


  get libxtest.a

  


  dir : /root/work/xtest.cu /root/work/include/xtest.h /root/work/lib/libxtest.a

  


  Then I copy root/work/include/xtest.h root/work/lib/libxtest.a to /root/work/FFmpeg/libavfiler direction
And add my fuc : int test() (which is in xtest.cu) to myfilter.c

  


  next

  


  ./configure \
  --prefix="$HOME/ffmpeg_build" \
  --pkg-config-flags="--static" \
  --extra-cflags="-I/root/work/include" \
  --extra-ldflags="-L/root/work/lib" \
  --extra-libs="-lpthread -lm" \
  --bindir="$HOME/bin" \
  --enable-gpl \
  --enable-gnutls \
  --disable-libaom \
  --enable-libass \
  --disable-libfdk-aac \
  --disable-libfreetype \
  --disable-libmp3lame \
  --disable-libopus \
  --disable-libvorbis \
  --disable-libvpx \
  --enable-nonfree

make


  


  error :

  


  AR  libavfilter/libavfilter.a
LD  ffmpeg_g
libavfilter/libxtest.a(vf_colorcalc.o): In function `colorcale_filter_frame':
/root/work/FFmpeg/libavfilter/vf_colorcalc.c:166: undefined reference to `test'
collect2: error: ld returned 1 exit status
Makefile:114: recipe for target 'ffmpeg_g' failed
make: *** [ffmpeg_g] Error 1



  


  please teach me how to build static lib to FFmpeg

  


• Evolution #3080 : filtre image_recadre et transparence

  3 mars 2020, par Emmanuel GUILLEMONT

  Confirmation de l’absence de transparence pour les images aux dimensions inférieures aux dimensions figurant comme arguments dans image_recadrex,y
  voir : https://a2c.mdr.zd.fr/?page=test
  squelette : https://a2c.mdr.zd.fr/sites/a2c.mdr.zd.fr/squelettes/test.html

  Voir aussi la discussion http://archives.rezo.net/archives/spip-dev.mbox/W4HB6TZA22JFIOCKHYG4HLVPLWRMA7YM/

• Dynamic subtitles by ffmpeg

  8 septembre 2019, par Saeron Meng

  I would like to add some commentary texts into my video but I do not know how to use ffmpeg to realize this. The comments are like screen bullets through the screen, appearing in the right margin, moving and scrolling, and disappearing from the left.

  My thought is to count the length of the comments and define speeds for them to move and I have already gotten the comments saved as an xml file. But even though I can transfer it into srt file, the tricky problem is, it is hard to write the speeds of the subtitles, or something like that, in an srt file, and apply them to ffmpeg commands or APIs. Here is an example of comments (xml file) :

  <chat timestamp="671.195">
  
      <ems utctime="1562584080" sender="Bill">
  
          <richtext></richtext>
  
      </ems>
  
  </chat>
  
  <chat timestamp="677.798">
  
      <ems utctime="1562584086" sender="Jack">
  
          <richtext></richtext>
  
      </ems>
  
  </chat>

  The final result is like this (I did not find an example in websites in English. In China, such moving subtitles are called "danmu" or "screen bullets"), these colorful characters can move horizontally from right to left :

  

  1. I have searched some solutions on the Internet, most of which talk about how to write ass/srt files and add motionless subtitles. Like this :

  ffmpeg -i infile.mp4 -i infile.srt -c copy -c:s mov_text outfile.mp4

  3
  
  00:00:39,770 --> 00:00:41,880
  
  When I was lying there in the VA hospital ...
  
  
  
  4
  
  00:00:42,550 --> 00:00:44,690
  
  ... with a big hole blown through the middle of my life,
  
  
  
  5
  
  00:00:45,590 --> 00:00:48,120
  
  ... I started having these dreams of flying.

  But I need another kind of "subtitles" which can move.

  2. When it comes to scrolling subtitles, there are still some solutions : Scrolling from RIGHT to LEFT in ffmpeg / drawtext

  So my question is, how to combine the solutions above to arrange subtitles from top to bottom and let them move concerning the timestamps of the comments ?