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• Correct way to dump yuv values after avcodec_decode_video2

  27 juin 2017, par Peter

  I am decoding H.265 raw data :

   avcodec_decode_video2(decoderCtx, pictYUV, &gotPicture, &packet)

  After the call, the value for pictYUV->format is AV_PIX_FMT_YUV420P as expected.

  I dump raw yuv values to a file as follows :

  fwrite(pictYUV->data[0], 1, w*h, f);
  
  fwrite(pictYUV->data[2], 1, w*h/4, f);
  
  fwrite(pictYUV->data[1], 1, w*h/4, f);

  For an input size of 640x480, when the file is viewed (using ImageMagick display utility), the image is what was expected.

  However, for an input size of 864x480, the image appears to be corrupted.

  What is interesting is if I run pictYUV through sws_scale, and dump the resulting yuv output, the image appears to be fine.

  sws_scale(swsCtx, pictYUV->data, pictYUV->linesize, 0, pictYUV->height,
  
    pictNewYUV->data, pictNewYUV->linesize);

  All I need is yuv data. I am hoping I can avoid the extra call to sws_scale. Wondering what is it that I am missing. Regards.

• Random error "Failed to update header with correct duration."

  22 juin 2017, par RMS

  I have a bash script that triggers a ffmpeg command, the loop strangely doesn’t start again after the error below randomly occurs :

  Failed to update header with correct duration.
  
  Failed to update header with correct filesize.

  I looked up everywhere, no luck. I dont mind the error, just why won’t the bash loop work correctly and relaunch the command ?

  I am running a nginx server where I push the stream to, here is the script :

  #!/bin/bash
  
  
  
  until ffmpeg -thread_queue_size 512 -re -I "external URL" -vcodec copy -vprofile baseline -acodec aac -strict -2 -f flv "nginx URL"; do
  
      echo "restarting ffmpeg command"
  
      sleep 1
  
  done 

  Thank you !

• Which is the correct key frame intervall settings for ffmpeg stream to Periscope

  28 septembre 2021, par Memo Can

  I will stream to Periscope with ffmpeg.
The requirements of Periscope are :

  



  •Framerate : 30fps
•Keyframe interval : every 2 seconds (OBS) or Keyframe every 45 frames (Wirecast)

  



  I have follew ffmpeg command line :

  



  ffmpeg -i INPUT -deinterlace -c:v libx264 -pix_fmt yuv420p -s 960x540 -preset superfast -vb 1200k -maxrate 1200k -r 30  -bufsize 8000k  -c:a aac -b:a 96k -ar 44100 -ac 2 -f flv rtmp://de.pscp.tv:80/xxxxxxxxx


  



  How can i set

  



  Keyframe interval: every 2 seconds (OBS) or Keyframe every 45 frames (Wirecast)  


  



  on this command line