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• Error writing to file when saving matplotlib animation with a given codec

  31 mars 2017, par idesh

  I’ve had trouble saving an mp4 animation created with matplotlib with a given codec. However I should mention beforehand that I could save the mp4 animation without specifying codecs and that seems to work fine, except that I am not able to insert this mp4 animation into powerpoint for a presentation. Powerpoint says it cannot read the file because it is missing 64bit codec.

  When digging further I discovered that Windows media player which is used by power point for the animations, has already some video codecs installed.

  So I thought of saving the initial matplotlib animation with one of these codecs, which is also compatible with ffmpeg. The command ffmpeg -codecs on terminal lists the supported codecs and I could spot the codecs common with ffmpeg and windows media player, ex : MSS1, MSS2

  So I tried to save the animation with the argument codec set as follows.

  anim = animation.FuncAnimation(fig, animate, 158,interval=300, blit=True)
  
  writer = animation.writers['ffmpeg']
  
  anim.save('film_v5.mp4', codec='mss1')

  Nevertheless it leads to an error, no matter what type of codec argument I put.

  So I was wondering perhaps there was someone savvy, willing to help me troubleshoot this problem. Despite my attempts I could not find any solution in the stackoverflow forum.

  Thank you in advance for your attention.

• HLS stream created by ffmpeg pauses every 5 seconds

  17 juillet 2017, par megacraft

  I am having problem remuxing an H264/AAC encoded file. There is a file on a server with H264-encoded video with AAC audio (example : input_video.mp4). An I-frame exists every 5 sec video. It is read by ffmpeg splitter/muxer application which splits and muxes it into 5 second video clips and then sends to the client over HLS protocol.

  While playing on client player there is a short pause every 5sec. This issue occurs only when ffmpeg higher than 2.4 is used, so in case ffmpeg pre 2.4.x is used (e.g., 2.0.8) then created video plays just fine.

  I have looked into https://github.com/FFmpeg/FFmpeg/blob/master/Changelog & https://github.com/FFmpeg/FFmpeg/blob/master/doc/APIchanges to spot changes in splitter/muxer but couldn’t find relevant info.

  Please give an answer or hints if you had a similar problem and solved it or have any idea what causes this issue.

• FFmpeg : Merge two videos using a transparent frame for the overlay video [closed]

  29 octobre 2024, par Major West

  I'm trying to overlay a video with another one that I'd like to place in the upper left corner and surround it with a transparent (bubble-)border using a png-file.

  


  The following milestones I've already achieved :

  


  

  • Placing the bubble at the right spot in the main video, retaining the transparency effect

  


  


  ffmpeg -i main.mp4 -loop 1 -i bubble.png -filter_complex "[1]format=yuva420p,fade=in:st=0:d=5:alpha=1[pip]; [0][pip]overlay=100:100:shortest=1" -c:v libx264 output_1.mp4


  


  

  • Placing the overlay video inside the bubble-border

  


  


  ffmpeg -y -i overlay.mp4 -loop 1 -t 1 -i bubble.png -filter_complex "color=black:d=1[c];[c][0]scale2ref[cs][v];[cs]setsar=1[ct]; [1:v]alphaextract,negate[m];[m][ct]scale2ref[ms][ol];[ms]setsar=1[alf]; [ol][alf]alphamerge[fin]; [v][fin]overlay,scale=1920:1080:force_original_aspect_ratio=decrease[fv]; [fv]pad=1920:1080:(ow-iw)/2:(oh-ih)/2:#000000@1[v]" -map "[v]" -map 0:a output_2.mp4


  


  (Maybe that one can be achieved a bit more efficiently I guess ...)

  


  What I cannot figure out is how to merge these two resulting files or how to do it in a single command, so that the transparency effect is not lost. Currently I'm getting a black border outside of the bubble when I'm done merging.

  


  So how can this be achieved using ffmpeg ?
  
And is there a way to do the second part a bit more efficiently ?