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• Deal with resolution changed while decoding ?

  30 juillet 2024, par TTGroup

  I'm using FFMPEG with C++ to read frames and decode them from RTSP Stream on IP Camera.

  


  Anything is ok, but while decoding, I try to change stream resolution config on IP Camera (ex : change from 1280x720 to 1920x1080).

  


  The result is av_read_frame() in while loop still read successful next frames (with new resolution) without error. So I can not detect that change to reinit buffer or reconnect stream to update other stream's information.

  


  av_read_frame() will read an AVPacket, If I can read resolution info in the AVPacket, then I can detect that change and reinit buffer. But I can't see any resolution info in AVPacket struct.

  


  How do I detect a resolution change while reading and decoding the stream ?

  


  ---

  


  I'm using many codecs as H264 and H265/H265+. This case happened with all 3 codecs above.

  


  In many cases, I also store the AVPacket for later playback, so there's no need for decode. I need to detect the resolution change immediately to be able to properly build header information to store on the HDD.

  


• Bulk Edit Videos resolution/aspect problem

  1er mars 2020, par buffe buffera

  Lets say i have 100 videos, all different dimensions and formats
  I would like to know if there’s a way to bulk edit each video and set it to 16:9 1920x1080
  If is possible would like to add blurred sides effect

  for %%a in ("C :\Users\vmp\Desktop\Videos\100ClipsConcat*.mp4") do ffmpeg -i "%%a" -lavfi "scale=1080:640,boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=1[bg] ;[bg][0:v]overlay=(W-w)/2 :(H-h)/2,setsar=1" "C :\Users\vmp\Desktop\Videos\100ClipsConcat\Blurred\%% na.mp4"
  pause

  Ive tried this and it blur add video but resolution isnt good

  Ive also tried to do that :

  ffmpeg -i 2.mp4 -lavfi "scale=ih*16/9 :-1,boxblur=luma_radius=min(h\,w)/20:luma_power=1:chroma_radius=min(cw\,ch)/20:chroma_power=1[bg] ;[bg][0:v]overlay=(W-w)/2 :(H-h)/2,crop=h=iw*9/16,setsar=1" r3.mp4

  It blur every video perfectly but it also increase resolution a lot

  I would just like to find something that convert each video to 1920x1080 16:9 (if is possible with blur effect)

• What resolution would be best for processing videos in firebase functions ? [closed]

  11 janvier 2020, par Nathan

  I’m making an app that is mainly used for sharing videos of maximum 30 seconds long. One video example could be a screen recording of someone’s computer screen or a game. I have this code that checks whether the uploaded video that has just been uploaded to firebase storage has been processed or not and if it hasn’t then I use ffmpeg to process the video (change the resolution etc.) with this command :

  const promise = spawn('./ffmpeg', ['-i', tempFilePath, '-vf', 'scale=1280:720', targetTempFilePath]);

  Now with these commands, the firebase function is giving me a timeout error when I upload 30 second clips since I’m only converting the video to 720. I was just wondering what compression settings would be sufficient enough for the video to :

  1. Be still a high enough quality in my app
  2. Not take ages processing the video in the function (10-20 second clips works perfectly well).

  I know the better option would be to use Googles App engine or something similar to process videos but I’d prefer it to avoid that at the moment, if I can’t process videos to a good enough quality without sacrificing efficiency then I will go to something like Google’s App engine, just need some advice and some pointers for it otherwise.

  EDIT :

  I’ve seen instagram compresses their videos to a resolution of 640x640 ? Would that be reasonable or is it dependent on the original clip’s resolution ?

  Thanks