Node.js & avconv — real-time video conversion

Question

I'm working on real-time video conversion demo app. Video file is parsed with node-multiparty, file's part is piped to avconv.stdin and when processed, the chunk pipes to write stream.

Here's a part of the source code:

var form = new multiparty.Form(),
    args = ['-i', 'pipe:0', '-f', 'webm', 'pipe:1'],
    avconv = spawn('avconv', args),
    output = fs.createWriteStream(filePath);

form.on('part', function (part) {
  if (part.filename) {
    part.pipe(avconv.stdin);

    part.on('end', function() {
      console.log('===== Video has been uploaded! =====');
      avconv.stdin.end();
    });
  }
});

avconv.stdout.pipe(output);

I'm interested in end event attached to file's part. Normally the event should be fired when a part is parsed, which means it has been uploaded.

I have a test video file (~800KB) and a low-level laptop for testing. While running a test on localhost, end event is firing at the very end of avconv conversion process, which lasts for ~15s.

800KB video file has been uploaded way faster, but it looks like the part stream is still not empty waiting for data to be processed by avconv.

Am I right or there's another thing?

Answer 1

You are absolutely right. The Readable stream emits end event only when it is totally consumed. Have a look here: http://nodejs.org/api/stream.html#stream_event_end