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• building c++ code into a shared library

  11 avril 2016, par gaurav

  I have some c++ code which i use as shared library in a java application.My c++ code uses some libraries like ffmpeg and boost. and ffmpeg libraries in turn depend on libx264. my first question is - can i build my c++ into a "fat" shared library which contains all the symbols from all libraries used so that on a new machine if i just copy the fat .so file everything works.
  If thats not possible then can you help me fix my current build process. This is what i am doing currently -

  1)on a local VM(ubuntu 64) i compile ffmpeg code using -fPIC flag and install h264 and boost using apt-get commands.
  2) on the same VM i compile my code using make file which looks like this-

  INCLUDES =   -I/opt/ffmpeg/include -I/usr/lib/jvm/java-7-openjdk-   amd64/include -I/usr/lib/jvm/java-7-openjdk-amd64/include/linux
  
  
  
  LDFLAGS =   -L/home/ubuntu/ffmpeg_shared
  
  
  
  LIBRARIES = -lavformat -lavcodec -lswscale -lavutil -lpthread  -lx264 -lboost_system -lboost_thread -lboost_chrono 
  
  
  
  CC = g++ -std=c++11 -fPIC
  
  
  
  all:clean final
  
  
  
  final:Api.o ImageSequence.o OverlayAnimation.o Utils.o ImageFrame.o 
  
  $(CC)  -o final.so Api.o ImageSequence.o OverlayAnimation.o Utils.o  ImageFrame.o $(LDFLAGS) $(LIBRARIES) -shared 

  3) on a new machine where java app will run. i install h264 and boost using apt-get commands and copy ffmpeg’s compiled library files to /usr/local/lib.

  4) copy the final.so file to this new machine. but when the java code tries to use the final.so file i see it tries to use wierdly named files. for example - it tries to find libavcodec.so.57 , libavformat.so.57 etc. to fix this i just created a copy of these files ie libavcodec.so copied to libavcodec.so.57.

  5)But these ffmpeg libraries in turn uses a differently named lib264.so file. on my new machine the apt-get command for x264 installed a file named libx264.so.148 but one of ffmpeg libraries is searching for file libx264.so.142 even if i rename this libx264.so file i get new errors where ffmpeg libraries tries to call libx264’s methods which has these numbers attached.

  6) at this time the only working option for me is to bring the c++ code on every new machine and build final.so file locally. this is something i want to avoid since i want to distribute the .so file along with jar file to my clients which they can easily use without having to build and install stuff.

• FFMPEG combining 2 command to make multiple overlay [closed]

  11 avril 2020, par Nano Wibisono

  I have two different commands and both work. but here I have a problem, how to combine these two commands into one output

  



  the first command is to add a video overlay

  



  ffmpeg -i   final.mp4    -vf "movie=LOGO.mov, scale=100: -1 [inner]; [in][inner] overlay =10: 10 [out] " completed.mp4


  



  the second command is to add a text overlay

  



  ffmpeg -i final.mp4 -vf drawtext="fontfile=C\\:/Windows/Fonts/arial.ttf:fontsize=20: fontcolor=red:x=10:y=50:text='test tect'" completedtextGB.mp4


  



  I was wondering is it possible to combine these into the 1 command ?

  



  Thanks
Nano

  


• Audio async after using setpts, converting to ts and concatenating

  11 janvier 2018, par Aurelius Schnitzler

  I am using f.i.

  ffmpeg -y -ss 00:00:09.664 -t 00:00:06.939 -i "test.mp4" -an -c:v libx264 -filter:v "setpts=0.1*PTS" test2.mp4

  to speed up a video by 10.

  But there is still audio in it when being used with

  ffmpeg -y -i test2.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts 2f.ts

  and

  ffmpeg -y -i "concat:2f.ts|..." -bsf:a aac_adtstoasc -movflags faststart -c copy final.mp4

  later on, yet every part’s audio in the final video is async.

  In some videos added with concat the video is not sped up, ie no -filter:v "setpts=0.1*PTS" and the audio is kept, ie no -an as in

  ffmpeg -y -ss 1 -t 2 -i "test3.mp4" -an -c:v libx264 test4.mp4
  
  ffmpeg -y -i test4.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts 4f.ts

  How do I mute the sped up parts and have audio not be async in the final video ?