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• Convert mp3 to AAC with mpeg-2 container (FFMPEG)

  18 mars 2016, par jsurf

  I’m trying to convert an mp3 audio file to an AAC file with FFMPEG, and I need the audio to be wrapped in an MPEG-2 container.
  The resulting AAC file needs to be AAC-LC (Low Complexity), 1-channel, CBR mode, 44100 sample rate, and 48kb/s bitrate, so I use this command :

  ffmpeg -y -i input.mp3 -ar 44100 -ab 48k -acodec libfdk_aac -ac 1 output.aac

  But when I examine the ADTS headers, the audio file is always being wrapped in an MPEG-4 container. I have tried all the codecs listed here but I still end up with an mpeg-4 container wrapped around the audio : http://trac.ffmpeg.org/wiki/AACEncodingGuide.

  Here are the headers I get when examining the AAC output file :

  mpeg_type : ’MPEG4’,
  profile : 2,
  profile_name : ’AAC LC’,
  sample_freq : 44100,
  channel_config : 1,
  channels : 1,
  frame_length : 139,
  buffer_fullness : 157,
  number_of_frames : 1,
  frames_per_sec : 43.06640625

  Any ideas as to why ffmpeg wraps an mp4 container around the audio ? Can I get around this somehow ? Are there any other encoders I can try aside from FFMPEG ? I was giving FAAC encoder a shot and it gives me the proper encoding and ADTS headers, but alas it does not support mp3, only WAV.

• Compiling FFMPEG on CentOS DigitalOcean

  29 juillet 2015, par coder_uk

  I set up a DigitalOcean instance running CentOS 6.5 and successfully followed the guide to compile FFMPEG (https://trac.ffmpeg.org/wiki/CompilationGuide/Centos). Hurrah !

  But of course I realised that by default, DigitalOcean creates a root user and so ffmpeg now lives in /root/bin/ffmpeg. Which isn’t ideal because when I want to exec the ffmpeg bin from nginx, I would have to run nginx as root for it to have permission.

  Questions ...

  1) Long-shot, but presumably if I change the owner of the ffmpeg binary to nginx, it still won’t work, because nginx won’t be able to access the /root folder it is in. Correct ?

  2) I could run nginx as root (’user root’). But this seems like a very bad idea. Correct ?

  3) Which leaves me with the option of creating a new user, and then compiling ffmpeg into its home folder. But : which user ? EC2 creates ’ec2-user’, so should I make my own equivalent for DO ? But then won’t I have to run nginx as that user, else I’ll run into the same problem ?

  Or should I compile ffmpeg into the ’nginx’ home folder, if indeed it has one ? Is that how it is supposed to be done ?

  Since compiling ffmpeg takes ages, I don’t want to keep doing it, and the static files all seem very out of date. Thanks

• parallel ffmpeg filter complex pipelines

  3 septembre 2021, par Paul Eppner

  Is there a possibility to run ffmpeg filter_complex filter in parallel pipelines ?
On the page http://trac.ffmpeg.org/wiki/Creating%20multiple%20outputs you can find an example under the heading "One filtering instance per each output". However, the filters mentioned there (boxblur,negate,yadif) are executed one after the other, although they could also all be executed simultaneously. I have quite complex filters and therefore long delays when the filters are executed one after the other.

  


  I hope there is another solution.
Cheers

  


  ---

  


  A few hours later I realised that the delay was probably not due to the pipeline, but to the analysis of the imports. However, I then only use the video and audio of the 1st stream. nevertheless, the delay time is then enormously high. Are there any ideas on how I can prevent this delay ?

  


      -i "rtmp://127.0.0.1:1935/$app/$name-de" \
    -i "rtmp://127.0.0.1:1935/$app/$name-en" \
    -i "rtmp://127.0.0.1:1935/$app/$name-fr" \
    -i "rtmp://127.0.0.1:1935/$app/$name-es" \
    -i "rtmp://127.0.0.1:1935/$app/$name-it" \
    -i "rtmp://127.0.0.1:1935/$app/$name-de" \
    -i "rtmp://127.0.0.1:1935/$app/$name-en" \
    -i "rtmp://127.0.0.1:1935/$app/$name-fr" \
    -i "rtmp://127.0.0.1:1935/$app/$name-es" \
    -i "rtmp://127.0.0.1:1935/$app/$name-it" \
    -i "rtmp://127.0.0.1:1935/$app/$name-de" \
    -i "rtmp://127.0.0.1:1935/$app/$name-en" \
    -i "rtmp://127.0.0.1:1935/$app/$name-fr" \
    -i "rtmp://127.0.0.1:1935/$app/$name-es" \
    -i "rtmp://127.0.0.1:1935/$app/$name-it" \
    -vsync -1 \
    -map 0:v -c:v:0 copy \
    -map 0:a \
    -c:a aac -ar 48000 \...```