Recherche avancée

Sur d’autres sites (3178)

• fftools/ffmpeg : simplify output stream initialization call graph

  25 mars 2023, par Anton Khirnov

  fftools/ffmpeg : simplify output stream initialization call graph
  Several places in the code currently call init_output_stream_wrapper(),
  
  which in turn calls init_output_stream(), which then calls either
  
  enc_open() or init_output_stream_streamcopy(), followed by
  
  of_stream_init(), which tells the muxer the stream is ready for muxing.
  All except one of these callers are in the encoding code, which will be
  
  moved to ffmpeg_enc.c. Keeping this structure would then necessitate
  
  ffmpeg_enc.c calling back into the common code in ffmpeg.c, which would
  
  then just call ffmpeg_mux, thus making the already convoluted call chain
  
  even more so.
  Simplify the situation by using separate paths for filter-fed output
  
  streams (audio and video encoders) and others (subtitles, streamcopy,
  
  data, attachments).
  

  • [DH] fftools/ffmpeg.c
  • [DH] fftools/ffmpeg_enc.c

• Linking to ffmpeg libraries fails while installing OpenCV

  12 août 2015, par Serhan

  FFMpeg 2.7.2 and all necessary libav* libraries are installed on my Ubuntu 14.04 machine. However, when I try to install OpenCV 2.4.11 (with FFMpeg enabled), I get the following error :

  /usr/bin/ld: cannot find -lavcodec
  
  /usr/bin/ld: cannot find -lswresample
  
  /usr/bin/ld: cannot find -lavutil
  
  /usr/bin/ld: cannot find -lavformat
  
  /usr/bin/ld: cannot find -lavcodec
  
  /usr/bin/ld: cannot find -lswresample
  
  /usr/bin/ld: cannot find -lavutil
  
  /usr/bin/ld: cannot find -lavformat
  
  collect2: error: ld returned 1 exit status
  
  make[2]: *** [bin/opencv_annotation] Error 1
  
  make[1]: *** [apps/annotation/CMakeFiles/opencv_annotation.dir/all] Error 2
  
  make: *** [all] Error 2

  I already tried pointing LD_LIBRARY_PATH and PKG_CONFIG_PATH to the locations which contain the FFmpeg libraries. I also tried with OpenCV 3.0 and obtained the same error.

  It seems that there is some kind of incompatibility between these versions of FFMpeg and OpenCV. Is there a workaround for this ?

  EDIT :
  For example locate libavcodec.a outputs :

  /home/guel/cvpr2014/bin/dependencies/ffmpeg-2.4/libavcodec/libavcodec.a
  
  /home/guel/cvpr2014/bin/dependencies/lib/libavcodec.a
  
  /home/guel/cvpr2014/bin/dependencies/opencv-2.4.9/3rdparty/lib/libavcodec.a
  
  /home/guel/ffmpeg_build/lib/libavcodec.a
  
  /home/guel/git/ffmpeg/libavcodec/libavcodec.a
  
  /home/guel/mplayer/ffmpeg/libavcodec/libavcodec.a
  
  /home/guel/projects/mpegflow/dependencies/opencv-2.4.11/3rdparty/lib/libavcodec.a

  So, I have it in multiple places. Is that bad ?

• Standardizing many mp4 files into same resolution

  22 novembre 2018, par Cowfod

  I have a huge collection of Instagram videos in different resolutions and with different audio codecs.

  Some videos are 640x640, others are 640x800. You get the picture.

  When I try to concat the videos, the video and audio go out of sync in the final output and the in some places the audio is slowed down(?).

  This is my ffmpeg concat command :

  ffmpeg -i "$(cat /home/list.txt)" -c:v copy -c:a copy /home/output.mp4

  list.txt contains over 800 clips and is formatted correctly :

  file 'clip1.mp4'
  
  file 'clip2.mp4'
  
  file 'clip3.mp4'
  
  etc...

  I believe the issue is due to all the different resolutions and different codecs used, so how can I standardize my collection of clips in order to concat them into a working video file ?