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• Why convert wav to mp3 get different length

  13 avril 2022, par sybil

  I use NAudio and NAudio.Lame to convert a wav file to mp3 file,code like that :

  


  using var reader = new WaveFileReader(file);
using var ms = new MemoryStream();
var writer = new LameMP3FileWriter(ms, reader.WaveFormat, 32);
reader.CopyTo(writer);
writer.Flush();
File.WriteAllBytes(file.Replace("wav", "mp3"), ms.ToArray());


  


  the wav file length is 1500ms,but the mp3 file length is 1557ms.

  


  And I do the same thing by using ffmpeg.exe,command like that :

  


  ffmpeg -i c:\2\xxx.wav c:\2\xxx.mp3


  


  the output info :

  


  ffmpeg version 5.0.1-essentials_build-www.gyan.dev Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 11.2.0 (Rev7, 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-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband
  libavutil      57. 17.100 / 57. 17.100
  libavcodec     59. 18.100 / 59. 18.100
  libavformat    59. 16.100 / 59. 16.100
  libavdevice    59.  4.100 / 59.  4.100
  libavfilter     8. 24.100 /  8. 24.100
  libswscale      6.  4.100 /  6.  4.100
  libswresample   4.  3.100 /  4.  3.100
  libpostproc    56.  3.100 / 56.  3.100
Guessed Channel Layout for Input Stream #0.0 : mono
Input #0, wav, from 'c:\2\xxx.wav':
  Duration: 00:00:01.50, bitrate: 768 kb/s
  Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz, mono, s16, 768 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (pcm_s16le (native) -> mp3 (libmp3lame))
Press [q] to stop, [?] for help
Output #0, mp3, to 'c:\2\xxx.mp3':
  Metadata:
    TSSE            : Lavf59.16.100
  Stream #0:0: Audio: mp3, 48000 Hz, mono, s16p
    Metadata:
      encoder         : Lavc59.18.100 libmp3lame
size=      12kB time=00:00:01.51 bitrate=  66.2kbits/s speed= 137x
video:0kB audio:12kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.928711%


  


  And I get a mp3 file which length is 1536ms.
So,why the length changed ?
Thanks for reading.

  


• What is wrong part in my Android code with ffmpeg ?

  6 janvier 2016, par Marko androshenko

  I want to get mixed video.(Image + Video)
  Total duration of original video is 180 sec. I want to put image to the front of video. So, I made some code in android studio.
  But I can not look any toast.
  What is wrong ? How to check the end of process ?

  ...
  path = "libray folder" ;
  ...

      private class ProcessVideo extends AsyncTask {
  
              @Override
  
              protected Void doInBackground(Void... params) {
  
  
  
                  Process ffmpegProcess = null;
  
  
  
                  try {
  
            // initialize command for process video
  
                // library is video process library.
  
                      String[] command ={path,"-i", input, "-r", "1", "-q:v", "2", "-f", "image", input};
  
  
  
  
  
                      ffmpegProcess = new ProcessBuilder(ffmpegCommand).redirectErrorStream(true).start();
  
  
  
                      OutputStream ffmpegOutStream = ffmpegProcess.getOutputStream();
  
                      BufferedReader reader = new BufferedReader(new InputStreamReader(ffmpegProcess.getInputStream()));
  
  
  
                      String line;
  
  
  
                      Log.v(THISTAG,"***Starting FFMPEG***");
  
                      while ((line = reader.readLine()) != null)
  
                      {
  
  // in progress 
  
                          Log.v(THISTAG,"***"+line+"***");
  
                      }
  
  // finish all process
  
                      Log.v(THISTAG,"***Ending FFMPEG***");
  
                      videoProcessFinishFlag = true;
  
  
  
                  } catch (IOException e) {
  
                      e.printStackTrace();
  
                  }
  
  
  
                  if (ffmpegProcess != null) {
  
                      ffmpegProcess.destroy();
  
                  }
  
                  return null;
  
              }
  
  
  
              protected void onPostExecute(Void... result) {
  
  // show result
  
                 Toast toast = Toast.makeText(VideoEditorActivity.this, "Done Processing Video", Toast.LENGTH_LONG);
  
                  toast.show();
  
              }
  
          }

• Merge commit '54dcd2288546e135986338107ea87db1fcedd633'

  19 mai 2017, par Clément Bœsch

  Merge commit '54dcd2288546e135986338107ea87db1fcedd633'
  * commit '54dcd2288546e135986338107ea87db1fcedd633' :
  
    als : Convert to the new bitstream reader
  This commit is a noop, see
  
  http://ffmpeg.org/pipermail/ffmpeg-devel/2017-April/209609.html
  Merged-by : Clément Bœsch <u@pkh.me>