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• How to slide mutiple images left continuously ?

  2 mai 2024, par mikezang

  I use ffmpeg to slide images from left to center as below :

  


  #slide 1st image from right to center
#countdown 10 seconds
#slide 1st image from center to left and in the same time
#slide 2nd image from right to center
#countdown 10 seconds
#...

ffmpeg -loglevel quiet -loop 1 -i input.png -filter_complex "split=2[bg][slider];[bg]drawbox=c=black:t=fill[bg];[bg][slider]overlay=x='max(W-w*t,0)':y=0" -t 10 -y output.mp4


  


  There is black background between two images, I want to the preious page keep slide from center to left and next page slide fron right to center, what can I do ?


  


• How come the quality of HEVC with alpha from my ffmpeg with videotoolbox is not ok

  27 juin 2023, par Jos

  I'm encoding ProRes 4444 with alpha channel video's to transparent video for web in both VP9 (webm) and HEVC (mp4). I'm using a great free tool by Rotato to encode to both formats at once.

  


  However, because I would like to have more control over e.g. the dimensions and the bitrate, I'm looking into ffmpeg. I can encode to both formats with the following params.

  


  # vp9
ffmpeg -i in.mov -vf scale=-1:720 -c:v libvpx-vp9 -auto-alt-ref 0 -pix_fmt yuva420p -acodec libvorbis -cpu-used 3 -deadline good -crf 40 out.webm 

# hevc
ffmpeg -i in.mov -vf scale=-1:720 -c:v hevc_videotoolbox -allow_sw 1 -alpha_quality 0.9 -tag:v hvc1 -q:v 65 out.mp4


  


  The problem : the videotoolbox encoder generates a weird white garbage around the black pencil animations and fade-in's from transparent to black pencil become fade-in's from white pencil to black pencil !?

  


  Here are screenshots of the two compared (top one is my ffmpeg output) :

  


  

  


  

  


  Anyone have good settings for ffmpeg I cano use to encode good quality HEVC with alpha ?
Hardware : MacBook Air M1 and Win11 + GTX 1060 (I should be able to use NVEnc, but don't know how)

  


• ffmpeg taking so much time to extract frames from mpeg-ts file

  19 septembre 2016, par Syed Azaruddin

  I got a problem from one mpeg-ts video. Actually it was created by some one else and even I don’t know how they are created. The problem is that, ffmpeg is taking so much time to decode all frames from the mpeg-ts video. The command I used for this operation is...

  ffmpeg -i shame-run.mov -r 24/1 test/output%d.jpg

  Actually my application is integrated with ffmpeg v2.1.1. and I had a code for detecting black frames in a mpeg-ts video. Here, my code is not able to detect all black frames from ffmpeg for this mpeg-ts video. So, I taken standalone ffmpeg of same version as mentioned above and decoded standalone. But, it is taking so much time i.e., it is taken half an hour for decoding 1 min duration video.

  So, is there any reason is that ffmpeg not able to extract as fast as required, and is there any reason that video got some errors.