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• Playing video with transparency in iOS

  14 juillet 2020, par 0Ds0

  A bit of background, i want to play videos with transparency on the web converted from gifs, for all non apple devices i can easily export a webm file like so

  


  ffmpeg -i test.gif -c:v libvpx-vp9 -qmin 0 -qmax 18 -crf 9 -b:v 1400K -quality good -cpu-used 0 -auto-alt-ref 0 -pix_fmt yuva420p -an -sn  -metadata title="test webm" test.webm

  


  No need for video streaming with HTTP response 206 partial content loaded it works out of the box

  


  Now for safari and apple devices i am presented with a totally different beast i set up a endpoint that serves the video with HTTP 206 responses and after a quite a struggle i can have the same end result for Safari in macOSX, and i convert the videos like so

  


  ffmpeg -i test.gif -qmin 0 -qmax 18  -vcodec prores_ks -q:v 64 -b:v 1400K  -pix_fmt yuva444p10le -profile:v 4444 -an -sn -metadata title="test mov" test.mov

  


  I put in the url address bar the that serves the video with stream and the video plays with transparency all good.

  


  Now on Safari in iOS the video just does not play, it is loaded with the same endpoint and other videos without transparency also work, serving from the same stream endpoint.

  


  Does anyone knows of a solution to encode a video with transparency that plays on all apple devices ?

  


  I also gave handbrake a try without success, actually could not even get the transparency right with handbrake.

  


• ffmpeg : capture two screens simultaneously, save as two separate files

  9 janvier 2017, par wetjosh

  Is this possible ? Here is my working single file solution. How can I modify it to save two separate files instead ?

  ffmpeg \
  
  -f avfoundation -pix_fmt uyvy422 -s 1440x900 -i 1 \
  
  -f avfoundation -pix_fmt uyvy422 -s 1440x900 -i 2 \
  
  -pix_fmt yuv420p -r 30 -preset ultrafast -b:v 5000k -t 15 \
  
    -filter_complex \
  
      "nullsrc=size=2880x900 [background]; \
  
      [0:v] setpts=PTS-STARTPTS, scale=1440x900 [left]; \
  
      [1:v] setpts=PTS-STARTPTS, scale=1440x900 [right]; \
  
      [background][left] overlay=shortest=1 [background+left]; \
  
      [background+left][right] overlay=shortest=1:x=1440 [left+right]" \
  
    -map [left+right] out.mov

  I’ve tried removing the filter complex. I’ve tried adding two output files. I’ve tried various combinations of mapping. The following is the closest I’ve gotten to making it work. It creates two files, but both contain only the second stream (-i 2).

  ffmpeg \
  
  -f avfoundation -pix_fmt uyvy422 -s 1440x900 -i 1 \
  
  -f avfoundation -pix_fmt uyvy422 -s 1440x900 -i 2 \
  
  -pix_fmt yuv420p -r 30 -preset ultrafast -b:v 5000k -t 15 out1.mov \
  
  -pix_fmt yuv420p -r 30 -preset ultrafast -b:v 5000k -t 15 out2.mov

• How can I save the downloaded and converted audios to a specific folder

  19 décembre 2022, par Retire Young

  I'm trying to download Videos from a specific playlist and converting it to a m4a file for further downloading. The process works perfectly but the files are being saved in the same folder where my Phyton script is located. I choose a specific Output Folder but the files don't appear there.
Any ways to save the files in the desired folder ?

  


  An error message reads as follows : "input.mp4: No such file or directory"
In my Code block, I censored the playlist link and the user name on the path. Just imagine a working playlist link instead. Thanks in advance !

  


  import os
import subprocess


  


  Replace with the URL of the YouTube playlist

  


  playlist_url = "PLAYLISTLINK"

  


  Set the output directory for the downloaded files

  


  output_dir = "/Users/USER/Documents/VideoBot/Output"

  


  Use youtube-dl to download the latest video in the playlist

  


  subprocess.run(["youtube-dl", "-f", "bestaudio[ext=m4a]", "--playlist-start", "1", "--playlist-end", "1", playlist_url])

  


  Extract the audio from the downloaded video using ffmpeg

  


  subprocess.run(["ffmpeg", "-i", "input.mp4", "-vn", "-acodec", "copy", "output.m4a"])

  


  Move the extracted audio file to the output directory

  


  os.rename("output.m4a", os.path.join(output_dir, "output.m4a"))