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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)

• ffmpeg set output resolution by resizing image

  3 janvier 2020, par Martin

  I’m trying to use ffmpeg for rendering video where an audio file and image are taken as inputs, and turned into a video (basically a music video) with the audio file playing for the duration of the video.

  My current working command :

  ffmpeg -loop 1 -framerate 2 -i "front.png" -i "testWAVfile.wav" -vf "scale=2*trunc(iw/2):2*trunc(ih/2),setsar=1,format=yuv420p" -c:v libx264 -preset medium -tune stillimage -crf 18 -c:a aac -shortest -vf scale=1920:1080  "outputVideo.mp4"

  Will set the output resolution of the video to whatever the resolution of the image is. Is there a way I can resize the image to enlarge it by a couple multiplications so that the output video resolution will be higher ?

  Like if my front.png image was 800x800 pixels, I could add something to my ffmpeg command to triple the resolution, so that the output video resolution is 2400x2400 ?