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• generating a video mosaic in client-side js

  1er novembre 2020, par redbrain

  I'm writing a web app for the creation of mosaic videos, where multiple videos can tiled next to each other, like a virtual meeting or grid of surveillance cameras. I'd like the user to be able to download their creation as an video file.

  


  I've currently been accomplishing this using a Node.js server to serve the rest of the site (which is static html/js) and then having one route execute ffmpeg and return the result. However, if this can be accomplished on the client side, the app would be easier to scale since I'd only have to serve static files, and nicer to write with only the client-side in mind.

  


  Does anyone know of a proper or clean way to do this ? I've looked at the following methods so far :

  


  

  • using ffmpeg ported to webassembly - this seems to be used constantly for any sort of client-side video editing ; however it seems overkill and clunky for this purpose

  


  • tiling all the videos in a <canvas></canvas> and rendering its output to an mp4 via the MediaStreamAPI - could be the best way, but it's not well documented

  


  


  If I'm missing something obvious, please let me know. I figured I would look further for the best method before writing further. Thanks in advance.

  


• ffmpeg/h265/opencv/c++ A method to resize frame after decoding on client side

  18 janvier 2018, par 8793

  I’ve just joined a project to build a realtime video streaming application using ffmpeg/opencv/c++ via udp socket. On server side, they want to transmit a video size (640x480) to client, in order to reduce data transmission through network I resize the video to (320x240) and send frame. On client side (client), after receiving frame, we will upscale the frame back to (640x480). Using H265 for encode/decoding.

  As I am just a beginner with video encoding, I would like to understand how to down-sampling & up-sampling the frame at server & client side in which we can incorporate with the video encoder/decoder.

  A simple idea came into my mind that after decoding avframe -> Mat frame, I will upsampling this frame then display it.

  I am not sure my idea is right or wrong. I would like to seek advice from any people who had experience in this area. Thank you very much !

  static void updateFrameCallback(AVFrame *avframe, void* userdata) {
  
      VideoStreamUDPClient* streamer = static_cast (userdata);
  
      TinyClient* client = static_cast (streamer->userdata);
  
  
  
      //Update Frame
  
      pthread_mutex_lock(&client->mtx_updateFrame);
  
      if (streamer->irect.width == client->frameSize.width
  
              && streamer->irect.height == client->frameSize.height) {
  
          cvtAVFrameYUV4202Frame(&avframe, client->frame);
  
          printf("TinyClient: Received Full Frame\n");
  
      } else {
  
          Mat block;
  
          cvtAVFrameYUV4202Frame(&avframe, block);
  
          block.copyTo(client->frame(streamer->irect));
  
      }
  
  
  
      //How to resize frame before display it!!!
  
  
  
      imshow("Frame", client->frame);
  
      waitKey(1);
  
      pthread_mutex_unlock(&client->mtx_updateFrame);
  
  }

• Is it possible .FLV to .MP4 conversion on client side by ffmpeg-asm.js ?

  24 mars 2016, par Egor M.

  Is it possible to do .FLV to .MP4 conversion on client side by ffmpeg-asm.js ?
  The main issue lot’s of mobile video players didn’t support flash, but .FLV still popular at the internet ;(

  Have no idea how to avoid server-side conversion and storing...