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• html5 video wont play ANY mp4 encodes on ipad

  12 mars 2019, par nickg

  Im trying to embed a mp4 on a page with the HTML5 video tag. Everything works fine on Desktop but nothing will work on an iPad Version 9.3.4.
  I have the mime types in an .htaccess file. I’ve tried various encodes with handbrake, Miro and FFmpeg conversions.

  Even sample videos like at w3schools and videojs don’t play.
  The video will play if i actually sync it to the iPad, but nothing works over the web. An older iPad actually plays mp4s through the HTML5 video player.
  I’m ready to throw this POS iPad through a window.

   <video autoplay="false" width="320" height="240" controls="true">
  
    <source src="http://webnamehere.com/video/bunny.mp4" type="video/mp4; codecs=&quot;avc1.42E01E, mp4a.40.2&quot;">
  
  
  
  Your browser does not support the video tag.
  
  </source></video>

  Has anyone found a way to fix this ? Is there ANY encoding that this thing will actually play ? Thank you in advance for any help.

• Got black screen when recording screen by x11grab device

  5 août 2019, par shawmzhu

  I’m trying to record video from a firefox run by xvfb-run but it always output nothing in the video file except black screen.

  Here’s what I did :

  start a firefox, open google.com :

  $ xvfb-run firefox https://google.com

  Then it will use the default display server number 99. I can see the display information by command xdpyinfo -display :99.

  A screenshot works very well by command :

  $ xwd -root -silent -display :99.0 | xwdtopnm |pnmtojpeg > screen.jpg

  Start using ffmpeg to record a video :

  $ ffmpeg -f x11grab -i :99.0 out.mpg

  When I play the video file out.mpg, there’s black screen all the time.

  Is there any parameter I missed ?

• ffmpeg decoding MP4 to Open GL texture black screen

  5 septembre 2019, par Dakiaiu

  I decoded a MP4 video and want to display the AVFrame via glTexImage2D and glTexSubImage2D but all I get is a blank GL Window.

  I’ve tried looking at the various examples in the ffmpeg github examples tree. https://github.com/FFmpeg/FFmpeg/tree/master/doc/examples and different posts from the past and recently on this site learning slowly from them but I could not find anything I am doing wrong.

  while(av_read_frame(format_context,packet) >= 0){
  
  
  
          if(packet->stream_index == video_stream_index){
  
  
  
              av_frame = decode(codec_context,av_frame,packet);
  
  
  
              sws_context = sws_getContext(codec_context->width,codec_context->height,codec_context->pix_fmt,codec_context->width,codec_context->height,
  
                      AV_PIX_FMT_RGB24, SWS_BICUBIC,nullptr,nullptr,nullptr);
  
  
  
              sws_scale(sws_context,
  
                      av_frame->data,
  
                      av_frame->linesize,
  
                      0,
  
                      codec_context->height,
  
                      gl_frame->data,
  
                      gl_frame->linesize);
  
  
  
              sws_freeContext(sws_context);
  
  
  
              if(first_use == true) {
  
  
  
                  glTexImage2D(GL_TEXTURE_2D,
  
                               0,
  
                               GL_RGB,
  
                               codec_context->width,
  
                               codec_context->height,
  
                               0,
  
                               GL_RGB,
  
                               GL_UNSIGNED_BYTE,
  
                               gl_frame->data[0]);
  
  
  
                  first_use = false;
  
  
  
              }else{
  
  
  
                  glTexSubImage2D(GL_TEXTURE_2D,
  
                          0,
  
                          0,
  
                          0,
  
                          codec_context->width,
  
                          codec_context->height,
  
                          GL_RGB,
  
                          GL_UNSIGNED_BYTE,
  
                          gl_frame->data[0]);
  
  
  
              }
  
  
  
          }
  
  
  
  
  
      }
  
  
  
  
  
      while( glfwGetKey(window, GLFW_KEY_ESCAPE ) != GLFW_PRESS &&
  
             glfwWindowShouldClose(window) == 0 );
  
  
  
  }

  The frames decode successfully but I cannot see anything. It has to be something with the above gl code that I have done wrong. I can show the ffmpeg code above if necessary.