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• What are the bad things that V8 Memory limitation can cause in a Node.js app ?

  9 octobre 2014, par scaryguy

  I’ve read several things about V8 Memory Limitation. Alas, I’m still not clear with it. Maybe it’s clear but I don’t want to believe. Here is my question :

  I have a Node.js application which will be hosted in a single physical server. This app will basically be an interface for some video related CPU and RAM heavy jobs. For example, I use FFMPEG to transcode videos within this application. And when doing this, I use child_processes of Node. Especially .spawn.

  My question is ;
  Since I’m running CPU and RAM intensive jobs inside a child_process, will I hook up to V8 Memory Limit (in a properly set 64bit system it’s 1.7GB) ?

  Because my FFMPEG processes will exhaust almost all resources of the server in production. Depending on the server configuration, it may use even 32GB of ram and tens of virtual CPU cores.

  I think I need some explanation on how child_processes work.

  Thank you

• lavfi/vaapi_vpp : Use dynamic frame pool in outlink if possible

  26 mars 2024, par Haihao Xiang

  lavfi/vaapi_vpp : Use dynamic frame pool in outlink if possible
  This can avoid to exhaust the buffers within outlink when libva2 is
  
  available.
  For example :
  
  $ ffmpeg -hwaccel_output_format vaapi -hwaccel vaapi -i input.mp4 \
  
   vf 'scale_vaapi=w=720:h=480' -c:v hevc_vaapi -f null -
  
  ...
  
  [vf#0:0 @ 0x55acad91f400] Error while filtering : Cannot allocate memory
  
  [vf#0:0 @ 0x55acad91f400] Task finished with error code : -12 (Cannot
  
  allocate memory)
  
  [vf#0:0 @ 0x55acad91f400] Terminating thread with return code -12
  
  (Cannot allocate memory)
  Signed-off-by : Haihao Xiang <haihao.xiang@intel.com>
  

  • [DH] libavfilter/vaapi_vpp.c

• Streaming a programatically created video to youtube using node and ffmpeg

  23 septembre 2020, par Caltrop

  I've been trying to Livestream a programmatically created image to youtube using node. I've had very limited success using FFmpeg. While I have managed to create and save an image thanks to this insightful thread, I have yet to make the code work for streaming to an RTMP server.

  


  const cp = require('child_process'),
    destination = 'rtmp://a.rtmp.youtube.com/live2/[redacted]', //stream token redacted
    proc = cp.spawn('./ffmpeg/bin/ffmpeg.exe', [
        '-f', 'rawvideo',
        '-pix_fmt', 'rgb24',
        '-s', '426x240',
        '-i', '-', //allow us to insert a buffer through stdin
        '-f', 'flv',
        destination
    ]);

proc.stderr.pipe(process.stdout);

(function loop() {
    setTimeout(loop, 1000 / 30); //run loop at 30 fps
    const data = Array.from({length: 426 * 240 * 4}, () => ~~(Math.random() * 0xff)); //create array with random data
    proc.stdin.write(Buffer.from(data)); //convert array to buffer and send it to ffmpeg
})();


  


  When running this code no errors appear and everything appears to be working, however, YouTube reports that no data is being received. Does anybody know what is going wrong here ?

  


  Update : This is really counter-intuitive but adding a slash to the destination like this 'rtmp://a.rtmp.youtube.com/live2/[redacted]/' causes ffmpeg to throw a generic I/O error. This is really weird to me. Apologies if the answer to this is obvious, I'm really inexperienced with ffmpeg.