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• 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);
  
  }

• Tips for encoding a live stream to IIS Media Services (or Azure Live Media Services) with FFMPEG ?

  6 mars 2014, par user3104748

  We're trying to encode assets, either live or static, in a live stream to IIS Media Services using ffmpeg. Can anyone provide pointers for exactly what kinds of parameters we should be using and setting ?

  As part of our test, just to see if we can get things to work, we have a standard plain-old MP4 video static asset that we're trying to stream to the server. It seems to work on the client side, but when we try to view the video on the receiving end, we get nothing.

  Here's an example of the command we're using, where gg.mp4 is the static MP4 video (obviously (hostname) is the name of our host and not the actual word in parenthesis :)...

  ffmpeg -y -re -i gg.mp4 -movflags isml+frag_keyframe -f ismv -threads 0 -c:a libvo_aacenc -ac 2 -b:a 64k -c:v libx264 -preset fast -profile:v baseline -g 48 -keyint_min 48 -map 0:v -b:v:0 477k -s:v:0 368x152 -map 0:v -b:v:1 331k -s:v:1 288x120 -map 0:v -b:v:2 230k -s:v:2 224x92 -map 0:a:0 http://(hostname)/ingest.isml/Streams(video)

• I ues FFMPEG to convert bitmap to yuv,and try to save it,but failed

  20 avril 2013, par liaoyuandeyehuo

  I use this way to convert bitmap to yuv
  Save bitmap to video (libavcodec ffmpeg)
  and then save the buffer like this :

  FILE* fp=fopen("aha.yuv","w");
  
  if(!fp) return NULL;
  
  fwrite(outPic->data[0],nbytes,1,fp);
  
  fwrite(outBuffer,nbytes,1,fp);
  
  fclose(fp);

  but it has only several lines. All most all of the .yuv file is gray.
  I am sure the inbuffer points to the input BGR32 data. So where is wrong ?
  Is The way to save the outBuffer right ?