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• Best way to have 2 youtube-dl input with ffmpeg and php

  8 janvier 2021, par Baraque Obahamas

  I'm trying to find the best way to combine a youtube-dl link in mp4 format with another youtube-dl link in m4a format to get an mp4 file through ffmpeg & php and to have an output in stdout in order to download the file directly.

  


  With only one file to convert to another format, I managed to do it easily, for example from m4a to mp3 :

  


  $cmd = "youtube-dl -f bestaudio[ext=m4a] --no-part --no-cache-dir --no-warnings --no-progress -o - https://www.youtube.com/watch?v=6Dh-RL__uN4 | ffmpeg -i - -f mp3 -ab 192k -";


  


  But with 2 inputs, it doesn't work :

  


  $cmd = "cat <(youtube-dl -f bestvideo[ext=mp4] --no-part --no-cache-dir --no-warnings --no-progress -o - https://www.youtube.com/watch?v=6Dh-RL__uN4) <(youtube-dl -f bestaudio[ext=m4a] --no-part --no-cache-dir --no-warnings --no-progress -o - https://www.youtube.com/watch?v=6Dh-RL__uN4) > ffmpeg -i - -movflags frag_keyframe+empty_moov+faststart -frag_duration 3600 -c:v copy -c:a copy -f mp4 -";


  


  In this case I get a "said into stderr : "sh : 1 : Syntax error : "(" unexpected")" error.

  


  I guess there must be a better way to do it.
I notice another problem is that on the ffmpeg command there is only one input "-i -". Now there are 2 inputs, there should be I guess "pipe:3" in addition, but so far my tests have not been conclusive.

  


  Full code :

  


  <?php
header('Content-Description: File Transfer');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header("Content-Disposition: attachment; filename=\"ok.mp4\"");
header("Content-Type: application/octet-stream");

$cmd = "cat <(youtube-dl -f bestvideo[ext=mp4] --no-part --no-cache-dir --no-warnings --no-progress -o - https://www.youtube.com/watch?v=6Dh-RL__uN4) <(youtube-dl -f bestaudio[ext=m4a] --no-part --no-cache-dir --no-warnings --no-progress -o - https://www.youtube.com/watch?v=6Dh-RL__uN4) > ffmpeg -i - -movflags frag_keyframe+empty_moov+faststart -frag_duration 3600 -c:v copy -c:a copy -f mp4 -";
$cmd = passthru($cmd, $status);


  


• alac : Check that the channels fit at the given offset

  3 septembre 2013, par Martin Storsjö

  alac : Check that the channels fit at the given offset
  The code tries to decode a number of channels at the
  
  offset given by the ff_alac_channel_layout_offsets table.
  
  Even if the number of channels decoded so far doesn’t
  
  exceed the total number of channels, we need to check that
  
  we actually can decode that number of channels at this offset
  
  as well.
  Reported-by : Mateusz "j00ru" Jurczyk and Gynvael Coldwind
  
  CC : libav-stable@libav.org
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/alac.c

• Merging RGB Channels in FFMPEG [migrated]

  14 octobre 2016, par Draconis

  I have three grayscale videos, representing the red, green, and blue channels from a video. I extracted them using the extractplanes filter, and sent them through different pipelines.

  Now I would like to combine them again. But while extractplanes is working perfectly, mergeplanes is not. My initial attempt was this :

  [r][g][b] mergeplanes=0x001020 [output]

  This interprets my RGB channels as YUV, which is not what I want. My next attempt was this :

  [r][g][b] mergeplanes=0x001020:rgb24 [output]

  But according to the error message, Only planar formats with more than one component are supported. (Same for all other RGB and RGBA pixel formats I tried.)

  Is there another way to put these channels back together ? Or some way to convince mergeplanes to output RGB ?