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• Converting YUV420P to BGRA ruins CPU

  21 septembre 2016, par Sun Dro

  I’m trying to write some media/stream player using chrome native-client (nacl) and ffmpeg. The problem is that nacl supports only BGRA and RGB formats and the stream I want to play is YUV420P.

  I solved this problem using FFMPEG

  int NCDecoder_DecodeVideo(NACLDecoder *pDec, AVFrame **ppFrame, AVPixelFormat pixFmt, int nWidth, int nHeight)
  
  {
  
      if (!pDec->bStarted) return 0;
  
  
  
      AVFrame *pFrame = *ppFrame;
  
      int nRetVal = avcodec_decode_video2(pDec->pCodecCtxV, pDec->pFrameV, &pDec->nGotFrameV, &pDec->vPkt);
  
      if(pDec->nGotFrameV)
  
      {
  
          if (!nWidth && !nHeight)
  
          {
  
              nWidth = pDec->pFrameV->width;
  
              nHeight = pDec->pFrameV->height;
  
          }
  
          else if (!nWidth || !nHeight)
  
          {
  
              if (nWidth) nHeight = nWidth * pDec->pFrameV->height / pDec->pFrameV->width;
  
              else nWidth = nHeight * pDec->pFrameV->width / pDec->pFrameV->height;
  
          }
  
  
  
          pFrame->width = nWidth;
  
          pFrame->height = nHeight;
  
          pFrame->format = pixFmt;
  
  
  
          pDec->pSwsCtx = sws_getCachedContext(pDec->pSwsCtx, pDec->pFrameV->width, pDec->pFrameV->height, 
  
              (AVPixelFormat)pDec->pFrameV->format, pFrame->width, pFrame->height, pixFmt, 0, NULL, NULL, NULL);
  
  
  
          sws_scale(pDec->pSwsCtx, (const uint8_t * const*)pDec->pFrameV->data, pDec->pFrameV->linesize, 0, 
  
              pDec->pFrameV->height, pFrame->data, pFrame->linesize);
  
  
  
          return 1;
  
      }
  
  
  
      return 0;
  
  } 

  Were argument pixFmt is AV_PIX_FMT_BGRA. Code works fine and I was happy until I try it on the full screen.

  When Im trying to scale image with full resolution, color format converting ruins my CPU memory and Its not even possible to watch video on the display.

  Is there any other fastest way to convert YUV to BGRA which not ruins my CPU usage or is there any way to display images using nacl-sdk with YUV color format ?

• Stream Video from Raspberry Pi to my Webpage

  21 septembre 2016, par velu4689

  I want to live stream the video captured on my SJ 4000 Camera.

  The Camera is Connected to my Rpi by Wi-Fi and the stream is available using the following address : rtsp ://192.168.1.254/sjcam.mov

  Now, I want to watch this stream in my webpage by using a Streaming Engine on Raspberry Pi.

  The rtsp ://Camera addr works when I Connected the Camera directly to my Windows PC and attempted using VLC. But I wanted to do it by using Rpi as the streaming engine.

  I have attempted the following :

  1) Using ffmpeg -i "rtsp ://[IP_ADDR]" -vcodec -f http://[my_pc_IP_ADDR]
  But am getting an error message "Unable to find a suitable output format for ’http://192.168.55.39:5678".

  2) Installed OMX Player. But I do not find proper material to stream using OMX Player.

  3) Have come across GStreamer. But still the same problem..I did not find proper material.

  Kindly provide your valuable inputs.

  Thanks.

• DIY video file streaming from linux/osx to iOS devices

  27 septembre 2016, par sfactor

  This is for a hobby project. I want to learn about video streaming and also create something that’s useful for me as well.

  The project should be able to run a server on my macbook and a client on my iPad that will allow me to watch the videos I’ve got stored on my laptop without having to copy them in my iPad over my wifi.

  I know there are solutions like Plex, Air Video etc. that allow me to do it. But since my goal is to practice writing some client/server code, I want to create something myself with the basic functionality of these apps.

  I figured I’d probably need something like ffmpeg and Apple’s HTTP Live Streaming (HLS), but I don’t have a Apple developer account to be able to use it. I do have Xcode in my mac. So, some free 3rd party library for HLS or something equivalent. I also fond this tool called https://www.bento4.com.

  How would I go about getting started with such an application and what are the libraries I could use to accomplish this ?