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• ffmpeg -concat slowing down AAC audio files

  28 août 2014, par Marc

  I am concatenating six m4a files with this command

  ffmpeg -f concat -i audiofiles.txt -c copy all_audio_edited.m4a

  each file has a duration of 6 hours (24 in total) but the concatenation doesn’t work quite well : the first part of the file (the first m4a) is perfect, but all the others are slowed down, so the final duration is >26 hours

  What’s wrong ?

  Thanks

  Marcs-MacBook-Pro:Sof marc$ ffmpeg -report -f concat -i audiofiles.txt -c copy all_audio_edited.m4a
  
  ffmpeg started on 2014-08-28 at 23:35:06
  
  Report written to "ffmpeg-20140828-233506.log"
  
  ffmpeg version 2.3 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Aug 26 2014 17:59:15 with Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid --enable-libfreetype --enable-libtheora --enable-libvorbis --enable-libvpx --enable-librtmp --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-aacenc --enable-libass --enable-ffplay --enable-libspeex --enable-libschroedinger --enable-libfdk-aac --enable-openssl --enable-libopus --enable-frei0r --enable-libcaca --enable-libquvi --enable-libvidstab --enable-libx265 --enable-libopenjpeg --extra-cflags='-I/usr/local/Cellar/openjpeg/1.5.1_1/include/openjpeg-1.5 '
  
    libavutil      52. 92.100 / 52. 92.100
  
    libavcodec     55. 69.100 / 55. 69.100
  
    libavformat    55. 48.100 / 55. 48.100
  
    libavdevice    55. 13.102 / 55. 13.102
  
    libavfilter     4. 11.100 /  4. 11.100
  
    libavresample   1.  3.  0 /  1.  3.  0
  
    libswscale      2.  6.100 /  2.  6.100
  
    libswresample   0. 19.100 /  0. 19.100
  
    libpostproc    52.  3.100 / 52.  3.100
  
  [concat @ 0x7fcb6c803400] Estimating duration from bitrate, this may be inaccurate
  
  Input #0, concat, from 'audiofiles.txt':
  
    Duration: 00:00:00.00, start: 0.000000, bitrate: 279 kb/s
  
      Stream #0:0: Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 280 kb/s
  
  Output #0, ipod, to 'all_audio_edited.m4a':
  
    Metadata:
  
      encoder         : Lavf55.48.100
  
      Stream #0:0: Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, 280 kb/s
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  size= 3020597kB time=26:07:14.44 bitrate= 263.1kbits/s    
  
  video:0kB audio:3004946kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.520849%

• use ffmpeg to cut video,the video will have extra duration

  17 juin 2021, par Venus

  ffmpeg -ss 2 -i input.mp4 -c copy -t 5 out.mp4


  


  after I executed the ffmpeg command.
  
the out.mp4 total have 7 seconds,it starts from the second frame of input.mp4 to the seventh frame of input.mp4.
  
It only has 5 effective seconds of the input.mp4, the last 2 seconds of input.mp4 is empty.

  


• airplay-js no start streaming

  24 août 2015, par Mikel David Carozzi Sanchez

  I’m writing a local file streaming over airplay protocol with subtitle support, to do that I’m using ffmpeg and the process works really fine, but the main problem is when I try to start streaming after burning the subtitle, the airplay doesn’t work, but when I comment the lines that do the burning works fine. What am I doing wrong ? Here is the code.

  var fileSource = './source.mp4';
  
  var subtitleSource = './source.srt';
  
  
  
  var http = require('http'),
  
  fs = require('fs'),
  
  util = require('util'),
  
  OS = require('os'),
  
  spawn = require('child_process').spawn,
  
  airplay = require('airplay-js');
  
  
  
  var browser = airplay.createBrowser();
  
  
  
  var tmpDir = OS.tmpdir();
  
  var tmpFile = tmpDir + '/localTV.mp4';
  
  
  
  var sourceSize;
  
  var tmpFileSize;
  
  
  
  function init(){
  
  console.log('Starting LocalTV');
  
  console.log('Burning Subtitle into ' + fileSource);
  
  
  
  var stat = fs.statSync(fileSource);
  
  sourceSize = stat.size;
  
  
  
  fs.exists(tmpFile, function(exists){
  
      if(exists) fs.unlink(tmpFile)
  
  });
  
  
  
  var ffmpeg = spawn('./ffmpeg', [
  
      '-i', fileSource,
  
      '-sub_charenc', 'CP1252',
  
      '-i', subtitleSource,
  
      '-map', '0:v',
  
      '-map', '0:a',
  
      '-c', 'copy',
  
      '-map', '1',
  
      '-c:s:0', 'mov_text',
  
      '-metadata:s:s:0', 'language=esp',
  
      tmpFile
  
  ]); 
  
  
  
  ffmpeg.stderr.pipe(process.stdout);
  
  
  
  ffmpeg.on('close', function(code){
  
      if(code == 0){
  
          console.log('Burning subtitle finished');
  
          initServer();
  
      }
  
  })
  
  
  
  ffmpeg.on('error', function(error){
  
      console.log(error, 'ffmpeg error');
  
  });
  
  
  
  //  initServer();
  
  
  
  return false;   
  
  }
  
  
  
  function initServer(){
  
  
  
  http.createServer(function (req, res) {
  
  
  
      var path = tmpFile;
  
      var stat = fs.statSync(path);
  
      var total = stat.size;
  
  
  
      if (req.headers['range']) {
  
          var range = req.headers.range;
  
          var parts = range.replace(/bytes=/, "").split("-");
  
          var partialstart = parts[0];
  
          var partialend = parts[1];
  
  
  
          var start = parseInt(partialstart, 10);
  
          var end = partialend ? parseInt(partialend, 10) : total-1;
  
          var chunksize = (end-start)+1;
  
  
  
          var file = fs.createReadStream(path, {start: start, end: end});
  
          res.writeHead(206, { 'Content-Range': 'bytes ' + start + '-' + end + '/' + total, 'Accept-Ranges': 'bytes', 'Content-Length': chunksize, 'Content-Type': 'video/mp4' });
  
          file.pipe(res);
  
  
  
        }else{        
  
  
  
          res.writeHead(200, { 'Content-Length': total, 'Content-Type': 'video/mp4' });
  
          fs.createReadStream(path).pipe(res);
  
      }
  
  
  
  }).listen(1337, '192.168.0.100', function(){
  
      console.log('HTTP Server Started');
  
      startStream();
  
  });
  
  
  
  return false;       
  
  }
  
  
  
  function startStream(){ 
  
  console.log('Streaming to AppleTV');
  
  
  
  var stat = fs.statSync(tmpFile);
  
  tmpFileSize = stat.size;    
  
  
  
  //  if(tmpFileSize >= sourceSize){
  
      browser.on('deviceOn', function(device) {
  
          device.play('http://192.168.0.100:1337', 0, function(status){
  
              console.info(status, 'Playing video');
  
          });
  
      });
  
  
  
      browser.on('error', function(err){
  
          console.log(err, 'Error airplay');
  
      })
  
  
  
      browser.start();
  
  //  }else{
  
  //      console.log('Temp file minor size that source, something is wrong');
  
  //  }
  
  
  
  return false;       
  
  }
  
  
  
  init();