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• FFMPEG - Get the exact calculated audio filesize after encode

  14 janvier 2016, par Youssef El Gharbaoui

  Im trying to guess an audio (mp3) filesize before encode with ffmpeg, afterward, need to have the exact calculated filesize.

  Here is the formula im using to predict and calculate the filesize (hope im not wrong) :

  ( Bitrates x Duration ) / 8) x 1000 = Filesize in Bytes.

  Im going to give a real example so that everyone can understand the use case.

  Example :

  Having an m4a file with the following data :

  • Name : Assuming xxx.m4a
  • Filesize : 8 304 014 bytes (8,3 Mo)
  • Bitrates : 256k
  • Duration : 260 seconds

  Expected filesize : ( (256 x 260) / 8 ) x 1000 = 8 320 000 bytes

  Then im running the following ffmpeg command :

  ffmpeg -i xxx.m4a -f mp3 -y -minrate 256k -maxrate 256k -bufsize 256k -b:a 256k -fs 8320000 output.mp3

  Console output :

  ffmpeg version 2.7.2 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.7.2_1 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang     --host-cflags= --host-ldflags= --enable-opencl --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-vda
  
    libavutil      54. 27.100 / 54. 27.100
  
    libavcodec     56. 41.100 / 56. 41.100
  
    libavformat    56. 36.100 / 56. 36.100
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 16.101 /  5. 16.101
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.100 /  1.  2.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'xxx.m4a':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2mp41
  
      encoder         : Lavf56.36.100
  
    Duration: 00:04:20.53, start: 0.000000, bitrate: 254 kb/s
  
      Stream #0:0(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 253 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
  Output #0, mp3, to 'output.mp3':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 512
  
      compatible_brands: isomiso2mp41
  
      TSSE            : Lavf56.36.100
  
      Stream #0:0(und): Audio: mp3 (libmp3lame), 44100 Hz, stereo, fltp, 256 kb/s (default)
  
      Metadata:
  
        handler_name    : SoundHandler
  
        encoder         : Lavc56.41.100 libmp3lame
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (aac (native) -> mp3 (libmp3lame))
  
  Press [q] to stop, [?] for help
  
  size=    8127kB time=00:04:20.02 bitrate= 256.1kbits/s    
  
  video:0kB audio:8127kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.011765%    

  Problem and Questions :

  • Can you tell me why im I getting an output with 8 322 546 bytes and
    not 8 320 000 as expected ?
  • Is there something wrong in my formula or the ffmpeg command ?
  • What solution can you suggest to get the exact predicted filesize ?

  Thank you in advance.

• Used more cpu than I set use more [closed]

  8 octobre 2023, par 张益铭

  The host gives Docker one CPU core to run ffmpeg in the container. When running ffmpeg (no limit like -threads) in the container, the htop command shows that at least seven ffmpeg processes are active and the total cpu usage exceeds 100%. When using the top command, the total cpu used by ffmpeg remains stable at 25%. What is the reason

  


  docker run like this

  


  docker run --name=ffmpeg --cpus=1 --memory=2048M -p 2222:22 -v /Users/zen/container:/data --privileged -dit alpine:3.18 ash


  


  ffmpeg command like this

  


  ffmpeg -i name.mkv name.mp4


  


  I think I set it up to only use one core and the program's cpu usage should be closer to 100% instead of 25%

  


• FFmpeg - Concatenate videos with not know format

  22 mars 2017, par Javier

  I am developing an application.
  People upload videos from their mobile, from other places.

  Using a CMS in PHP (it is the language with which the application is developed) I need to generate a unique video with these partial uploads.

  Through FFmpeg I am doing tests, from the command line :

  ffmpeg -i concat:IMG_1916.mp4\|IMG_1917.mp4 -c copy videoLoop.mp4

  This code when I run it says :

  ffmpeg version 3.2.4 Copyright (c) 2000-2017 the FFmpeg developers
  built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  configuration : —prefix=/usr/local/Cellar/ffmpeg/3.2.4 —enable-shared —enable-pthreads —enable-gpl —enable-version3 —enable-hardcoded-tables —enable-avresample —cc=clang —host-cflags= —host-ldflags= —enable-libmp3lame —enable-libx264 —enable-libxvid —enable-opencl —disable-lzma —enable-vda
  
      libavutil      55. 34.101 / 55. 34.101
  
      libavcodec     57. 64.101 / 57. 64.101
  
      libavformat    57. 56.101 / 57. 56.101
  
      libavdevice    57.  1.100 / 57.  1.100
  
      libavfilter     6. 65.100 /  6. 65.100
  
      libavresample   3.  1.  0 /  3.  1.  0
  
      libswscale      4.  2.100 /  4.  2.100
  
      libswresample   2.  3.100 /  2.  3.100
  
      libpostproc    54.  1.100 / 54.  1.100
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f8515000000] Found duplicated MOOV Atom. Skipped it Input #0, mov,mp4,m4a,3gp,3g2,mj2, from ’concat:IMG_1916.mp4|IMG_1917.mp4’ :
  
  Metadata :
      encoder : Lavf57.66.102
  
      major_brand : isom
  
      minor_version : 512
  
      compatible_brands : isomiso2avc1mp41
  Duration : 00:00:04.27, start : 0.000000, bitrate : 26792 kb/s
      Stream #0:0(und) : Video : h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1920x1080, 11978 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  Metadata :
      handler_name : VideoHandler
  Stream #0:1(und) : Audio : aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 120 kb/s (default)
  
  Metadata :
      handler_name : SoundHandler
  Output #0, mp4, to ’videoLoop.mp4’ :
  Metadata :
      compatible_brands : isomiso2avc1mp41
  
      major_brand : isom
  
      minor_version : 512
  
      encoder : Lavf57.56.101
  
      Stream #0:0(und) : Video : h264 (Constrained Baseline) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080, q=2-31, 11978 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc (default)
  Metadata :
      handler_name : VideoHandler
  Stream #0:1(und) : Audio : aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, mono, 120 kb/s (default)
  
  Metadata :
      handler_name : SoundHandler
  Stream mapping :
      Stream #0:0 -> #0:0 (copy)
  
      Stream #0:1 -> #0:1 (copy)
  Press [q] to stop, [?] for help
  
  frame=  127 fps=0.0 q=-1.0 Lsize=    6264kB time=00:00:04.22 bitrate=12142.8kbits/s speed= 376x    
  
  video:6196kB audio:63kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead : 0.076698%
  

  This execution generates a video, but not concatenated with the 2 specified, only with the first one.

  Why not join the 2 ?

  The videos to upload, will be of very different formats so I can not define codec.