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• FFMPEG for aws s3 bucket signed url not working in node js

  21 août 2018, par ahmed sharief

  I am trying to create thumbnails from an amazon s3 bucket signed url. I am able to generate thumbnails when i run the command in terminal

  ffmpeg -ss 00:00:02 -i "https://test-s3-bucket.s3.ap-south-1.amazonaws.com/user_gallery_assets/5b6936069ac2bf0602085367/gallery/images/5b7be08527641dee8c1f8134.mp4?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=xxxxxxxxx%2F20180821%2Fap-south-1%2Fs3%2Faws4_request&X-Amz-Date=20180821T095101Z&X-Amz-Expires=900&X-Amz-Signature=d7f81f4eed3d6c87c04dc1b0ad06beeb946afa33d417585f57fad72aeadb3ac0&X-Amz-SignedHeaders=host" -vframes 1 -q:v 2 -f image2 output.jpg

  I am running the above command in terminal and its working fine but when i try to implement the same in node js its showing "no such file or directory error". Though i am encoding the url with double quotes then also its showign same error. Here is my node js code....

  function uploadThumbNailForVideo(obj,url, thumb_url){
  
      return new Promise((resolve, reject) => resolve(url))
  
      .then((url) => awsHelper.getImage(url))
  
      .then((result) => { 
  
  
  
          var resUrl = "\""+result+"\"";
  
  
  
          var args = [ 
  
              '-i', resUrl, 
  
              '-ss', '00:00:02', 
  
              '-vframes', '1', 
  
              '-f','image2', 
  
              'output.jpg'
  
          ]
  
          //console.log(args)
  
          var ffmpeg = require('child_process').spawn('ffmpeg', args);
  
  
  
          ffmpeg.on('error', function (err) {
  
              console.log(err);
  
          });
  
  
  
          ffmpeg.on('close', function (code) {
  
  
  
          });
  
  
  
          ffmpeg.stderr.on('data', function (data) {
  
              var tData = data.toString('utf8');
  
              var a = tData.split('\n');
  
              console.log("A",a); 
  
          });
  
  
  
          ffmpeg.stdout.on('data', function (data) {
  
              //
  
          });
  
  
  
  
  
      });

  }

  and i am getting the following error

  A [ 'ffmpeg version 4.0.2 Copyright (c) 2000-2018 the FFmpeg 
  
  developers' ]
  
  A [ '',
  
    '  built with Apple LLVM version 9.1.0 (clang-902.0.39.2)',
  
    '  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.0.2 --enable- 
  
  shared --enable-pthreads --enable-version3 --enable-hardcoded-tables -- 
  
  enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable- 
  
  gpl --enable-libmp3lame --enable-libx264 --enable-libxvid --enable- 
  
  opencl --enable-videotoolbox --disable-lzma',
  
     '  libavutil      56. 14.100 / 56. 14.100',
  
     '  libavcodec     58. 18.100 / 58. 18.100',
  
    '  libavformat    58. 12.100 / 58. 12.100',
  
    '  libavdevice    58.  3.100 / 58.  3.100',
  
    '  libavfilter     7. 16.100 /  7. 16.100',
  
    '  libavresample   4.  0.  0 /  4.  0.  0',
  
    '  libswscale      5.  1.100 /  5.  1.100',
  
    '  libswresample   3.  1.100 /  3.  1.100',
  
    '  libpostproc    55.  1.100 / 55.  1.100',
  
    '"https://test-s3-bucket.s3.ap-south-1.amazonaws.com/user_gallery_assets/5b6936069ac2bf0602085367/gallery/images/5b7be08527641dee8c1f8134.mp4?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=xxxxxxxxx%2F20180821%2Fap-south-1%2Fs3%2Faws4_request&X-Amz-Date=20180821T095101Z&X-Amz-Expires=900&X-Amz-Signature=d7f81f4eed3d6c87c04dc1b0ad06beeb946afa33d417585f57fad72aeadb3ac0&X-Amz-SignedHeaders=host": No such file or directory',
  
    '' ]
  
  
  
  ffmpeg exited with code 1

• How to synchronise two audio files using a marker

  30 juillet 2014, par Dimitri Jorge

  I’m working on a project on which we use WebRTC and the RecordRTC library to record audio files.

  I would like to be able to process the audio files server-side to ensure a good synchronisation.

  To do so, I’m thinking about marking the start of each record with an inaudible sound marker in order to analyse new records and then manipulate the starting offset with ffmpeg (which I already use to compress the raw files created by RecordRTC).

  The thing is I’ve never done any advanced audio processing before, I’m looking around and cannot find what would be the proper way to do this.

  Is there another, better, way to handle synchronisation ? And if not, I would be grateful if I could get some tips on the marker technique.
  Thank you.

  Edit :
  I forgot to mention for those who don’t know how RecordRTC works that the record is done client-side in Javascript. The synchronisation issue comes from the fact that javascript is not good at synchronising calls.

  The process is done as follow :

  1) A user records himself

  [User 1] -> Records on his browser an audio file
  
     |
  
     | Saves raw audio file (call it audio_1.ogg)
  
     |
  
  [Server]

  2) Another user wants to join user_1’s project

  [User 2]  <--- Fetch audio_1.ogg (in an audio html tag) --- [Server]
  
     |
  
     | Press record
  
     |
  
  [Webapp] -> Plays audio_1.ogg and starts recording audio_2.ogg
  
     |
  
     | Saves audio_2.ogg when record is over
  
     |
  
  [Server]

  The synchronisation issue comes from the fact that there are no way in Javascript to ensure that both the functions handling that starts record and the one responsible for beginning playing the existing audio file happen on the same time.

  I end up with 50/100 ms of gap depending on how many audio files are already on the project (since it’s not limited to two).

• Can Linux buffer UDP packets to correct the sequence

  6 avril 2021, par QuickPrototype

  Good Day,

  


  I am transmitting MP3 audio using UDP through the Internet. Yes, it's most likely a bad idea for various reasons, however my use case limits me to this setup. To expand further based on comments below, my source device connects over a very high latency link with low and limited throughput as these devices are located in rural/remote areas. My latency is up to 1 seconds (shocking yes). Using TCP will therefore degrade my service due to its two way coms, acks, resends and the likes.

  


  The issue I'm trying to resolve is that on the receiver server (Linux Ubuntu 18.04), I am seeing all the packets but many times slightly out of sequence. I.e. packet 5 comes before packet 4.

  


  Is there a way in Linux to buffer the incoming UDP stream such that consumers (FFMPEG in my case) is able to get stream in order (being a buffer, with an expected delay, that would be linked to buffer size).

  


  Tcpdump example of issue (note : ids are out of sequence) :

  


  16:04:48.648448 IP (tos 0x0, ttl 24, id 25335, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80
16:04:48.648503 IP (tos 0x0, ttl 24, id 25334, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:48.884324 IP (tos 0x0, ttl 24, id 25336, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:48.884357 IP (tos 0x0, ttl 24, id 25337, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80
16:04:49.145213 IP (tos 0x0, ttl 24, id 25339, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80
16:04:49.145257 IP (tos 0x0, ttl 24, id 25338, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:49.406068 IP (tos 0x0, ttl 24, id 25340, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:49.406125 IP (tos 0x0, ttl 24, id 25341, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80
16:04:49.667095 IP (tos 0x0, ttl 24, id 25342, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:49.667175 IP (tos 0x0, ttl 24, id 25343, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80
16:04:49.929139 IP (tos 0x0, ttl 24, id 25344, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:49.929200 IP (tos 0x0, ttl 24, id 25345, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80
16:04:50.164307 IP (tos 0x0, ttl 24, id 25346, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:50.164385 IP (tos 0x0, ttl 24, id 25347, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80
16:04:50.425221 IP (tos 0x0, ttl 24, id 25348, offset 0, flags [DF], proto UDP (17), length 1228)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 1200
16:04:50.425285 IP (tos 0x0, ttl 24, id 25349, offset 0, flags [DF], proto UDP (17), length 108)
    xx.xx.xx.xx.2011 > 172.xx.xx.xx.2011: UDP, length 80