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• H264 fragments to Image Files

  19 novembre 2020, par Harsh Solanki

  first time here so be gentle.

  


  I followed following :

  


  H264 ByteStream to Image Files

  


  with this, I am able to correctly generate an image for the very first fragments.

  


  However, when I am trying for the subsequent fragments (.h264), I am getting following error :

  


  [h264 @ 0x5a8f640] Format h264 detected only with low score of 1, misdetection possible !
[h264 @ 0x5a8f640] Could not find codec parameters for stream 0 (Video : h264, none) : unspecified size
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, h264, from 'frame-0003.h264' :
Duration : N/A, bitrate : N/A
Stream #0:0 : Video : h264, none, 24 tbr, 1200k tbn, 48 tbc
Output #0, image2, to 'output.png' :
Output file #0 does not contain any stream

  


  My fragments are named in following manner :

  


  frame-0001.h264, frame-0002.h264 ..... frame-1500.h264

  


  Is there any way I can create images for all the 1500 fragments. Any guidance, help or code is very appreciated.

  


• FFMPEG image not updating

  4 juillet 2017, par Liam Martens

  THE INPUT FILES

  1. An overlay image that has is being updated every 5 seconds by a Python script
  2. A small MP4 file that will be looped by a concat input
  3. An MP3 file as audio source

  THE COMMAND (UPDATED)

  This is the command I’m currently using to combine and stream the inputs.

  ffmpeg -re -i music.mp3 -f concat -i videoincludes.txt
  
  -r 1 -loop 1 -f image2 -i overlay.png
  
  -c:v libx264 -c:a aac -shortest -crf 23 -pix_fmt yuv420p
  
  -maxrate 2500k -bufsize 2500k -preset ultrafast -r 30 -g 60 -b:v 2000k -b:a 192k -ar 44100
  
  -filter_complex "[1:v][2:v] overlay=0:0" -map 0:a -strict -2
  
  -f flv rtmp://a.rtmp.youtube.com/live2/{key}

  Als tried using -framerate 1 instead of -r 1

  THE ISSUE

  So the issue is that the image doesn’t always update. Sometimes it does update every couple seconds at the start but it stops updating after 10-20 seconds without any difference in log output and sometimes it just doesn’t update.

  I can however confirm that the image is being updated by the Python script but FFmpeg is just not picking this up.

  I read setting the input format of the image to image2 should allow it to update so I am not sure what is wrong or what I can do to improve it.

• FFmpeg - center crop image overlay

  21 juillet 2020, par ClassA

  Here is the information about my input files, player and command I'm using :

  


  

  


  

  • Input Video Dimensions = 1080 x 1920

  


  • Input Image Dimensions (overlay - Red in image) = 1080 x 1794

  


  • Player dimensions (Black in image) = 1080 x 1794

  


  • Video size (scaled to fit in player - Blue in image) = 1010 x 1794

  


  


  My current command is :

  


  -ffmpeg -ss valueLeft -i inputVideo -i inputOverlay -t to -filter_complex scale=playerWidth:trunc(ow/a/2)*2,overlay=(main_w-overlay_w)/2:(main_h-overlay_h)/2 -c:v libx264 -preset ultrafast outputPath


  


  The playerWidth is the width of the video, scaled to fit in the player (blue/video in the image above).

  


  ---

  


  The problem I have is that the video is scaled inside the player to fit inside the player, this means that I might have values like 999.

  


  To counter this, I can change the width to 998 or 1000, but the overlay image will be out by one pixel. I know one pixel is not a lot, but in my use case, it has to be precisely the same as it was in the player.

  


  Besides that, the video aspect ratio will also change when doing this.

  


  My question :

  


  How can I center crop the overlay, despite the size of the video or the overlay image, to get the following result :

  


  

  


  EDIT :
It would be great if I could instead use the video's original dimensions and crop the overlay (if it is bigger than the video).