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• ffmpeg : Extracted wav from mp4 video does not have equal duration as the original video

  26 juillet 2021, par John Smith

  I have a mp4 video that is 0.92 seconds, and I am trying to extract the audio of the video to a wav format. I have tried several commands (I have provided a list of some of the commands that I have tried), however, the resulting wav does not have the same duration as the original video (the resulting wav often has a duration of 0.96 seconds instead of 0.92 seconds). Ensuring that the video and audio are synchronous is crucial for what I am doing (the videos are typically videos of a person speaking, and it is important that the speech (audio) is in-sync with the mouth movements of the speaker).

  


  I find it odd that, by extracting audio from a video, the duration changes, even despite what is happening under the hood for the conversion (in terms of codecs used, etc).

  


  Some of the commands that I've tried include :

  


  ffmpeg -i <input /> -c copy -map 0:a -sample_rate 16000 <output>&#xA;&#xA;ffmpeg -i <input /> -async  1 -f wav <output>&#xA;&#xA;ffmpeg -i <input /> -vn -acodec copy <output>&#xA;&#xA;ffmpeg -i <input /> -ac 2 -f wav <output>&#xA;</output></output></output></output>

  


  Any insight would be highly appreciated.
Thanks !

  


  Edit Output of the command ffmpeg -ignore_editlist true -i 00026.mp4 output.wav

  


  ffmpeg version 2021-02-28-git-85ab9deb98-full_build-www.gyan.dev Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 10.2.0 (Rev6, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-lzma --enable-lib
snappy --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-sdl2 --enable-libdav1d --enable-libzvbi --enable-librav1e --enable-libsvtav1 --en
able-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libvidstab --e
nable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libglslang --enable-vulkan --
enable-opencl --enable-libcdio --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwben
c --enable-libilbc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --en
able-libsoxr --enable-chromaprint
  libavutil      56. 66.100 / 56. 66.100
  libavcodec     58.126.100 / 58.126.100
  libavformat    58. 68.100 / 58. 68.100
  libavdevice    58. 12.100 / 58. 12.100
  libavfilter     7.107.100 /  7.107.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '00026.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf57.37.101
  Duration: 00:00:00.98, start: 0.000000, bitrate: 599 kb/s
  Stream #0:0(und): Video: mpeg4 (Simple Profile) (mp4v / 0x7634706D), yuv420p, 160x160 [SAR 1:1 DAR 1:1], 556 kb/s, 25 fps, 25 tbr, 12800 tbn, 25 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]
  Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 16000 Hz, mono, fltp, 65 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]
Stream mapping:
  Stream #0:1 -> #0:0 (aac (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
Output #0, wav, to 'output.wav':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    ISFT            : Lavf58.68.100
  Stream #0:0(und): Audio: pcm_s16le ([1][0][0][0] / 0x0001), 16000 Hz, mono, s16, 256 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      vendor_id       : [0][0][0][0]
      encoder         : Lavc58.126.100 pcm_s16le
size=      32kB time=00:00:00.96 bitrate= 273.7kbits/s speed= 212x
video:0kB audio:32kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.238037%


  


• FFMPEG video merging. Only first video shows

  13 mars 2019, par James Ashworth

  I’m trying to put 7 second intro video before another one, but I keep having trouble with it. I don’t need to do anything else then add intros to videos.

  This is what I’m currently getting.

  (for %i in (*.mp4) do @echo file '%i') > mylist.txt
  
  
  
  ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4
  
  
  
  
  
  
  
  
  
  
  
      C:\Users\Business>cd desktop
  
  
  
  C:\Users\Business\Desktop>cd testfile
  
  
  
  C:\Users\Business\Desktop\Testfile>(for %i in (*.mp4) do @echo file '%i') > mylist.txt
  
  
  
  C:\Users\Business\Desktop\Testfile>
  
  C:\Users\Business\Desktop\Testfile>(for %i in (*.mp4) do @echo file '%i') > mylist.txt
  
  
  
  C:\Users\Business\Desktop\Testfile>ffmpeg -f concat -i mylist.txt -c copy output.mp4
  
  ffmpeg version N-93308-g1144d5c96d Copyright (c) 2000-2019 the FFmpeg developers
  
    built with gcc 8.2.1 (GCC) 20190212
  
    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-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-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt  
  
  
  
  libavutil      56. 26.100 / 56. 26.100
  
    libavcodec     58. 47.103 / 58. 47.103
  
    libavformat    58. 26.101 / 58. 26.101
  
    libavdevice    58.  6.101 / 58.  6.101
  
    libavfilter     7. 48.100 /  7. 48.100
  
    libswscale      5.  4.100 /  5.  4.100
  
    libswresample   3.  4.100 /  3.  4.100
  
    libpostproc    55.  4.100 / 55.  4.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 00000261c7072c00] Auto-inserting h264_mp4toannexb bitstream filter
  
  Input #0, concat, from 'mylist.txt':
  
    Duration: N/A, start: -0.042667, bitrate: 2453 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 2325 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s
  
      Metadata:
  
        handler_name    : SoundHandler
  
  Output #0, mp4, to 'output.mp4':
  
    Metadata:
  
      encoder         : Lavf58.26.101
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, q=2-31, 2325 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc
  
      Metadata:
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s
  
      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=110209 fps=3246 q=-1.0 Lsize= 1103461kB time=01:01:17.41 bitrate=2458.1kbits/s speed= 108x
  
  video:1042171kB audio:57353kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.358030%
  
  
  
  C:\Users\Business\Desktop\Testfile>

  It shows the 7 second video as the whole video. Someway i got it to change after 7 seconds, but then the rest of the video was really buddy.

• how much time ffmpeg take on an average of making video 15 sec

  24 mars 2016, par sumit saini

  I am doing coding in ffmpeg in android for making a () video using ffmpeg. In which I am take one background image + one tom +.wav then try to make video like talking tom but problem is that it take lot of time in 15 sec video = 1 minute. please tell how to minimise time.

  my code is below

  commandText = "-loop 1 -r "+frameRate+" -i /sdcard/emoj/bg.png -r "
  
                      + frameRate
  
  + " -f concat -i /sdcard/emoj/images.txt -i /sdcard/emoj/final.wav -filter_complex [1:v]scale="+mitiWidth+":"+mitiHeight+"[ovrl];[0:v][ovrl]overlay=(main_w-overlay_w)/2:(main_h-overlay_h) -s "+deviceWidth +"x"+deviceHeight+" -preset ultrafast -codec:v libx264 -c:a aac -pix_fmt yuv420p -strict experimental -b:a 32k -t 00:00:"+ time +" /sdcard/emoj/myPetVideo.mp4";

  image.txt is tom images .

  please tell me if any buddy know or tell which library is used in talking tom.

  Thanks