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• TV Screen gittery while sending Stream using FFMPEG Android

  24 septembre 2019, par Arvind

  I am getting issue while i am sending the stream to wowza using FFMPEG on RTMP
  issue is stream working good sending to wowza but issue is while sending its making android tv screen gittery probable what i found this is because its taking time on transcoding and UI thread gets hang

  let me show you my command :

  -i - -strict experimental -acodec aac -ac 1 -ar 44100 -vcodec libx264 -pix_fmt yuv420p -g 8 -vb 26k -profile:v main -preset ultrafast -r 8 -f flv -threads 0 -async 1 -vsync 1 rtmp://origin.cdn.wowza.com:1935

  and below some log :

   D/From the FFMPEG: frame=   51 fps= 13 q=40.0 size=      85kB time=00:00:06.52 bitrate= 107.0kbits/s dup=6 drop=273 speed=1.61x    
  
  09-24 03:27:42.094 2189-2189/com.addwatchhdmi.app D/Execute onProgress: frame=   51 fps= 13 q=40.0 size=      85kB time=00:00:06.52 bitrate= 107.0kbits/s dup=6 drop=273 speed=1.61x    

• How to insert bullet screen comments into a video by using ffmpeg ?

  7 septembre 2019, par Saeron Meng

  I would like to add some real-time comments in my video but I do not know how to use ffmpeg to realize this. The comments are like screen bullets through the screen, scrolling from right to left.

  My thought is to count the length of the comments and define speeds for them to move. Don’t worry about the source of the comments, I have already gotten them saved as an xml file. Also, I can transfer it into srt. For instance :

  <chat timestamp="671.195">
  
      <ems utctime="1562584080" sender="Bill">
  
          <richtext></richtext>
  
      </ems>
  
  </chat>
  
  <chat timestamp="677.798">
  
      <ems utctime="1562584086" sender="Jack">
  
          <richtext></richtext>
  
      </ems>
  
  </chat>

  The final result is like this (I did not find an example displayed in English), these fancy characters can move horizontally :

  

  I have searched some solutions on the Internet, most of which talk about how to write ass/srt files and add motionless subtitles. Like this :

  3
  
  00:00:39,770 --> 00:00:41,880
  
  When I was lying there in the VA hospital ...
  
  
  
  4
  
  00:00:42,550 --> 00:00:44,690
  
  ... with a big hole blown through the middle of my life,
  
  
  
  5
  
  00:00:45,590 --> 00:00:48,120
  
  ... I started having these dreams of flying.

  ffmpeg -i infile.mp4 -i infile.srt -c copy -c:s mov_text outfile.mp4

  But I need another kind of "subtitles" which can move.

  So my question is, how to modify the ffmpeg command and the template of srt file so as to arrange the subtitles from the top to the bottom and let them move from right to left ?

• 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.