Advanced search

On other websites (11857)

• Support Polymer DOM + module loaders combo

  3 July 2014, by JamesMGreene

  Support Polymer DOM + module loaders combo
  Fixes #446.
  
  Closes #452.
  

• Combining multiple mp4s with python-ffmpeg wrapper

  30 August 2020, by Perchful

  So I'm working on a program that downloads multiple mp4s to a folder and then concats them together. I've run into a few problems while using the FFMPEG python wrapper. At first, I was able to combine the videos using the code, but there is no audio for some reason.

  


      filenames = []
        inputs = []



        dlnumber = 1

        #Actual downloading of mp4s

        while dlnumber <= len(user_timeline):
            subprocess.call(r'youtube-dl.exe ' + user_timeline[dlnumber-1]['url'] + ' -o' + str(os.getcwd()) + r'\DLvideo' '\\u' + str(dlnumber) + '.%(ext)s')
            subprocess.call('ffmpeg -i ' + str(os.getcwd()) + r'\DLvideo\u' + str(dlnumber) + '.mp4' + ' -r 60 -vf scale=1920:1080 -ar 44100 ' + str(os.getcwd())+ r'\DLvideo\f' + str(dlnumber) +'.mp4')


            filenames.append(str(os.getcwd())+ r'\DLvideo\f' + str(dlnumber) +'.mp4')
            os.remove(str(os.getcwd()) + r'\DLvideo\u' + str(dlnumber) + '.mp4')

            dlnumber +=1

        for filename in filenames:
            inputs.append(ffmpe.input(filename))

#FFMPEG CONCAT
        (   ffmpeg
            .concat(*inputs)
            .output('TEST.mp4')
            .run()
        )


  


  I've also heard about separating the audio and video, making changes, and then combining them together again, and while I was able to separate the audio and the video, I couldn't exactly figure out how to combine them individually, and then together again. Would love some help. Thanks.

  


• Combining audio and video streams in ffmpeg in nodejs

  10 July 2015, by LouisK

  This is a similar question to Merge WAV audio and WebM video but I’m attempting to deal with two streams instead of static files. It’s kind of a multi-part question.

  It may be as much an ffmpeg question as a Node.js question (or more). I’ve never used ffmpeg before and haven’t done a ton of streaming/piping.

  I’m using Mauz-Khan’s MediaStreamCapture (an expansion on RecordRTC) in conjunction with Socket.io-stream to stream media from the browser to the server. From webkit this delivers independent streams for audio and video which I’d like to combine in a single transcoding pass.

  Looking at FFmpeg’s docs it looks like it’s 100% capable of using and merging these streams simultaneously.

  Looking at these NPM modules:

  https://www.npmjs.com/package/fluent-ffmpeg and https://www.npmjs.com/package/stream-transcoder

  Fluent-ffmpeg’s docs suggest it can take a stream and a bunch of static files as inputs, while stream-transcoder only takes a single stream.

  I see this as a use case that just wasn’t built in (or needed) by the module developers, but wanted to see if anyone had used either (or another module) to accomplish this before I get on with forking and trying to add the functionality?

  Looking at the source of stream-transcoder it’s clearly setup to only use one input, but may not be that hard to add a second to. From the ffmpeg perspective, is adding a second input as simple as adding an extra source stream and an extra ’-i’ in the command? (I think yes, but can foresee a lot of time burned trying to figure this out through Node).

  This section of stream-transcoder is where the work is really being done:

  /* Spawns child and sets up piping */
  
  Transcoder.prototype._exec = function(a) {
  
  
  
      var self = this;
  
  
  
      if ('string' == typeof this.source) a = [ '-i', this.source ].concat(a);
  
      else a = [ '-i', '-' ].concat(a);
  
  
  
      var child = spawn(FFMPEG_BIN_PATH, a, {
  
          cwd: os.tmpdir()
  
      });
  
      this._parseMetadata(child);
  
  
  
      child.stdin.on('error', function(err) {
  
          try {
  
              if ('object' == typeof self.source) self.source.unpipe(this.stdin);
  
          } catch (e) {
  
              // Do nothing
  
          }
  
      });
  
  
  
      child.on('exit', function(code) {
  
          if (!code) self.emit('finish');
  
          else self.emit('error', new Error('FFmpeg error: ' + self.lastErrorLine));
  
      });
  
  
  
      if ('object' == typeof this.source) this.source.pipe(child.stdin);
  
  
  
      return child;
  
  
  
  };

  I’m not quite experienced enough with piping and child processes to see off the bat where I’d add the second source - could I simply do something along the lines of this.source2.pipe(child.stdin) ? How would I go about getting the 2nd stream into the FFmpeg child process?