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• Audio fade in and looping

  30 juin 2020, par BIOStheZerg

  I'm trying to put some background music to a video with a person speaking. The background music should face in over a few seconds. The music is a short snippet, which loops really well. I tried to loop it via ffmpeg so that I have everything in one command :

  


  ffmpeg -i video_file.mp4 -f lavfi -i amovie=audio_file.wav:loop=0 -filter_complex '[0:a] volume=2.0 [voice]; [1:a] afade=in:st=0:d=5, volume=0.1 [soundtrack]; [voice][soundtrack] amix=inputs=2:duration=shortest' -codec:v copy out_file.mp4


  


  (this is a simplified version, the real one has a side chain compress as well, but that's irrelevant)

  


  The thing that doesn't work for me is the combination of the looping and the afade filter - every iteration of the background music fades in on its own. How could I do this such that only the first one fades in and the others just "continue" playing ? Is it possible to do it in a single command ?

  


  I know I could pre-loop a certain number of iterations based on the video length, but that would require creating a possibly large file (or lose audio quality via compression).

  


  Thanks !

  


• convert ogv to webm using ffmpeg and point ffmpeg to new installed version

  9 juin 2015, par Aisha

  I was facing problem in converting files from one format to another, so I put the question on stackoverflow, some people suggested me to recompile ffmpeg my ffmpeg version was 0.10.0 so they suggest me to install new one with full codecs from this link

  https://trac.ffmpeg.org/wiki/CompilationGuide/Centos

  I followed the steps and installed new version but i didnot uninstall my old one and its still giving me error when i am converting video from ogv to webm

   /root/bin$ ffmpeg -i hello.ogv -acodec libvorbis -ac 2 -ab 96k -ar   44100 hello.webm
  
   ffmpeg version 0.10.15 Copyright (c) 2000-2014 the FFmpeg developers
  
   built on Aug 30 2014 15:49:19 with gcc 4.4.7 20120313 (Red Hat 4.4.7-3)
  
   configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share      /ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64          --mandir=/usr/share/man --arch=x86_64 --extra-cflags='-O2 -g   -pipe -Wall      -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector             --param=ssp-buffer-size=4 -m64 -mtune=generic' --enable-bzlib --disable-crystalhd --enable-gnutls --enable-libass --enable-libcdio --enable-libcelt --enable-libdc1394 --disable-indev=jack --enable-libfreetype --enable-libgsm --enable-libmp3lame --enable-openal --enable-libopenjpeg --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libx264 --enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-runtime-cpudetect
  
  libavutil      51. 35.100 / 51. 35.100
  
  libavcodec     53. 61.100 / 53. 61.100
  
  libavformat    53. 32.100 / 53. 32.100
  
  libavdevice    53.  4.100 / 53.  4.100
  
  libavfilter     2. 61.100 /  2. 61.100
  
  libswscale      2.  1.100 /  2.  1.100
  
  libswresample   0.  6.100 /  0.  6.100
  
  libpostproc    52.  0.100 / 52.  0.100
  
  Input #0, ogg, from 'hello.ogv':
  
  Duration: 00:01:30.00, start: 0.000000, bitrate: 435 kb/s
  
  Stream #0:0: Video: theora, yuv420p, 400x320 [SAR 1:1 DAR 5:4], 25 fps, 25 tbr, 25 tbn, 25 tbc
  
   Stream #0:1(und): Audio: vorbis, 44100 Hz, stereo, s16, 128 kb/s
  
   Metadata:
  
     CREATION_TIME   : 2013-02-16 05:41:59
  
     LANGUAGE        : und
  
    HANDLER_NAME    : /tmp/tmpGzy9a1/448616221878309._audio.aac - Imported with GPAC 0.4.6-DEV-rev3544
  
    MAJOR_BRAND     : FACE
  
    MINOR_VERSION   : 1337
  
    COMPATIBLE_BRANDS: isomavc1FACE
  
    ENCODER         : Lavf55.37.102
  
    [buffer @ 0x2143160] w:400 h:320 pixfmt:yuv420p tb:1/1000000 sar:1/1    sws_param:
  
    Output #0, webm, to 'hello.webm':
  
    Stream #0:0: Video: none, yuv420p, 400x320 [SAR 1:1 DAR 5:4], q=2-31,  128 kb/s, 90k tbn, 25 tbc
  
     Stream #0:1(und): Audio: none, 44100 Hz, 2 channels, s16
  
     Metadata:
  
      CREATION_TIME   : 2013-02-16 05:41:59
  
       LANGUAGE        : und
  
       HANDLER_NAME    : /tmp/tmpGzy9a1/448616221878309._audio.aac -         Imported with GPAC 0.4.6-DEV-rev3544
  
       MAJOR_BRAND     : FACE
  
       MINOR_VERSION   : 1337
  
      COMPATIBLE_BRANDS: isomavc1FACE
  
       ENCODER         : Lavf55.37.102
  
    Stream mapping:
  
     Stream #0:0 -> #0:0 (theora -> ?)
  
     Stream #0:1 -> #0:1 (vorbis -> libvorbis)
  
     Encoder (codec none) not found for output stream #0:0

  I know i have to point to new ffmpeg build. but how to do this. Please help me. I am desperate.

• avcodec/ra144enc : Fix invalid left shift of negative number

  22 janvier 2020, par Andreas Rheinhardt

  avcodec/ra144enc : Fix invalid left shift of negative number
  by replacing it with a multiplication. Said multiplication can't
  
  overflow an int32_t because lpc_coefs is limited to 16 bit precision.
  Fixes the FACE-test acodec-ra144 as well as part of #8217.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/ra144enc.c