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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%

• How to process a video to mp4 with ffmpeg for quality and compatibility ?

  30 mai 2024, par Luis A. Florit

  I am beginning to be more serious about video. I am processing my videos with ffmpeg in a fully updated Linux into mp4 to use it in HTML5 directly.

  


  Now, I have old AVI videos that I want to convert to mp4 with ffmpeg for use with HTML5. In particular, I have this one :

  


  http://luis.impa.br/photo/1101_aves_ce/caneleiro-de-chapeu-preto_femea_Quixada-CE-110126-E_05662+7a.avi

  


  (I know, terrible quality... sorry). According to ffprobe :

  


  Duration: 00:01:35.30, start: 0.000000, bitrate: 1284 kb/s
Stream #0:0: Video: mpeg4 (Simple Profile) (DX50 / 0x30355844), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 1144 kb/s, 30 fps, 30 tbr, 30 tbn, 30 tbc
Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 44100 Hz, stereo, s16p, 128 kb/s


  


  That seems perfect : mpeg4 video and mp3 audio. So I tried :

  


  ffmpeg -i input.avi -acodec copy -vcodec copy output.mp4


  


  It generates a file that plays nicely in mplayer, but not in firefox getting an error :

  


  Video format or MIME type not supported.


  


  Chrome plays the audio, but no video is shown... Now, if I do :

  


  ffmpeg -i input.avi output.mp4


  


  firefox works, but the video is reencoded in another one with half the size (half the bitrate). This is what ffprobe says about the reencoded video :

  


  major_brand     : isom
minor_version   : 512
compatible_brands: isomiso2avc1mp41
encoder         : Lavf57.71.100
Duration: 00:01:35.30, start: 0.000000, bitrate: 685 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x480 [SAR 1:1 DAR 4:3], 548 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default)


  


  I suppose that I am loosing lots of quality (and time processing the video). So, my questions :

  


  


  1. Why are browsers not playing my video with the copy codecs ?

     


  


  2. Can I work with ffmpeg in this particular file without reencoding ? If yes, how ?

     


  


  3. If I need to reencode, which are "reasonable" parameters to keep close to the original quality ? Would something like

     


     ffmpeg -i input.avi -b:v 1024k -bufsize 1024k output.mp4

     


  


  


  suffice for this video ? This generates a new video with size closer to the original one.

  


  Thanks !

  


• ffmpeg app using node occasionally crashes as file doesn't appear to be read correctly

  31 mai 2022, par Zabs

  I have an simple Node application that allows me to pass an AWS S3 URL link to a file (in this case video files). It uses the FFMPEG library to read the video file and return data like codecs, duration, bitrate etc..

  


  The script is called from PHP script which in turn send the data to the Node endpoint and passes the Amazon S3 URL to node. Sometimes for no obvious reasons the video file fails to return the expected values regarding container, codec, duration etc... and just returns '0'. But when I try the exact same file/request again it returns this data correctly e.g container:mp4

  


  I'm not sure but I think the script somehow needs the createWriteStream to be closed but I cannot be sure, the problem is the issue I have found doesn't happen all the time but sporadically so its hard to get to the issue when its difficult to replicate it.

  


  Any ideas ?

  


  router.post('/', async function(req, res) {
  const fileURL = new URL(req.body.file);
  var path = fileURL.pathname;
  path = 'tmp/'+path.substring(1);    // removes the initial / from the path

  let file = fs.createWriteStream(path);  // create the file locally
  const request = https.get(fileURL, function(response) {
    response.pipe(file);
  });
  
  // after file has saved
  file.on('finish', function () {
    var process = new ffmpeg(path);
    process.then(function (video) {
      let metadata = formatMetadata(video.metadata);

      res.send ({
        status: '200',
        data: metadata,
        errors: errors,
        response: 'success'
      });

    }, function (err) {
      console.warn('Error: ' + err);

      res.send ({
        status: '400',
        data: 'Something went wrong processing this video',
        response: 'fail',
      });
    });
  });

  file.on('error', function (err) {
    console.warn(err);
  });

});

function formatMetadata(metadata) {
  const data = {
    'video' : metadata.video,
    'audio' : metadata.audio,
    'duration' : metadata.duration
  };
  return data;
}


  


  // Expected output

  


  {"data":{"video":{"container":"mov","bitrate":400,"stream":0,"codec":"h264","resolution":{"w":1280,"h":720},"resolutionSquare":{"w":1280,"h":720},"aspect":{"x":16,"y":9,"string":"16:9","value":1.7777777777777777},"rotate":0,"fps":25,"pixelString":"1:1","pixel":1},"audio":{"codec":"aac","bitrate":"127","sample_rate":44100,"stream":0,"channels":{"raw":"stereo","value":2}},"duration":{"raw":"00:00:25.68","seconds":25}}


  


  // Actual output

  


  {"data":{"video":{"container":"","bitrate":0,"stream":0,"codec":"","resolution":{"w":0,"h":0},"resolutionSquare":{"w":0,"h":null},"aspect":{},"rotate":0,"fps":0,"pixelString":"","pixel":0},"audio":{"codec":"","bitrate":"","sample_rate":0,"stream":0,"channels":{"raw":"","value":""}},"duration":{"raw":"","seconds":0}}


  


  Note - this happens sporadically