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• ffmpeg error "Output file is empty, nothing was encoded" when trying to increase the tempo (speed up) mp3 file

  28 octobre 2022, par rasoolZero

  I'm trying to increase the tempo of an mp3 file using ffmpeg and atempo filter, but always get "Output file is empty, nothing was encoded"

  


  this is the output log

  


  ffmpeg version 4.3.1 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 10.2.1 (GCC) 20200726
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libsrt --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libgsm --disable-w32threads --enable-libmfx --enable-ffnvcodec --enable-cuda-llvm --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
  libavutil      56. 51.100 / 56. 51.100
  libavcodec     58. 91.100 / 58. 91.100
  libavformat    58. 45.100 / 58. 45.100
  libavdevice    58. 10.100 / 58. 10.100
  libavfilter     7. 85.100 /  7. 85.100
  libswscale      5.  7.100 /  5.  7.100
  libswresample   3.  7.100 /  3.  7.100
  libpostproc    55.  7.100 / 55.  7.100
[mp3 @ 0000023bf37fdbc0] Estimating duration from bitrate, this may be inaccurate
Input #0, mp3, from 'normal.mp3':
  Metadata:
    encoder         : Lavf58.65.100
  Duration: 00:00:05.93, start: 0.000000, bitrate: 32 kb/s
    Stream #0:0: Audio: mp3, 22050 Hz, mono, fltp, 32 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (mp3 (mp3float) -> mp3 (mp3_mf))
Press [q] to stop, [?] for help
[mp3_mf @ 0000023bf3822880] MFT name: 'MP3 Encoder ACM Wrapper MFT'
Output #0, mp3, to 'faster.mp3':
  Metadata:
    TSSE            : Lavf58.45.100
    Stream #0:0: Audio: mp3 (mp3_mf), 22050 Hz, mono, s16, 128 kb/s
    Metadata:
      encoder         : Lavc58.91.100 mp3_mf
size=       0kB time=00:00:05.42 bitrate=   0.7kbits/s speed= 116x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Output file is empty, nothing was encoded (check -ss / -t / -frames parameters if used)


  


  this is the command I'm using
ffmpeg -i normal.mp3 -af "atempo=1.1" faster.mp3

  


• FFmpeg : How to change tempo dynamically

  25 octobre 2018, par Ankush

  I am working on an android project in which I need to change the tempo of an mp3 (50 seconds audio) file dynamically as shown :

        Time            |    Tempo
  
   ----------------------------------------------
  
        0-4             |     1.0    
  
                        |    
  
        4-8             | change form 1.0 to 0.5 
  
                        |
  
        8-12            |     0.5
  
                        |
  
        12-16           | change from 0.5 to 1
  
                        |
  
        16-20           |     1
  
                        |
  
        20-24           | change from 1 to 1.5
  
                        |
  
        24-28           |     1.5
  
                        |
  
        28-32           | change from 1.5 to 1
  
                        |
  
        32-36           |     1
  
                        |
  
        36-40           | change from 1 to 1.5
  
                        |
  
        40-44           |     1.5
  
                        |
  
        44-48           | change from 1.5 to 1
  
                        |
  
        48-50           |     1

  I had searched and found that I can use atempo for this. But it changes the whole audio tempo. I think that I can split the audio and apply the effect but it also not work for this type of dynamic task. Please help me to find the solution. Thank you in advance :)

• lavfi/atempo : fix tempo range limit inconsistency

  4 octobre 2018, par Pavel Koshevoy

  lavfi/atempo : fix tempo range limit inconsistency
  yae_set_tempo was overlooked when max tempo limit was raised to 100.
  tested with :
  
  ./ffmpeg_g -i Delerium/SemanticSpaces/Gateway.mp3 \
  
   af asendcmd=f=asendcmd.cfg,atempo=1.0 -y /tmp/asendcmd-atempo.wav
  where asendcmd.cfg was :
  
  15.0-45.0 [enter] atempo tempo 2.0,
  
            [leave] atempo tempo 0.5 ;
  60.0-300.0 [enter] atempo tempo 4.0,
  
             [leave] atempo tempo 1.0 ;
  

  • [DH] libavfilter/af_atempo.c