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• How can I output every other TS packet (of an MPEG Transport Stream file), into one output file, using FFMPEG ?

  9 août 2022, par mustardCutter

  I want to copy every other MPEG transport stream packet (PID# 00000000 [I'm guessing this is the first #], 00000002, 00000004...), from one MPEG transport stream file, into one output file, and the other ones (PID# 00000001, 00000003, 00000005...) into another output file. The output files don't have to be MPEG transport stream files ; they could be PCM, etc. Each packet could perhaps be referenced by stream id (PID #) or by Bytes, as each one is 188 Bytes, except perhaps the last packet.

  


  I'd prefer to not use HLS or sequence muxer or concat if they require that I separate all the TS packets from one TS file into a folder first (as that would make many thousands of them), and I'd rather not deal with log or text or playlist files if I don't have to do so. I can't rename the PIDs, as their naming should remain what it is for a later step. I can't glob since it isn't an image file, though if I have to, perhaps I can read it in as if it's an image file sequence and glob so as to group the odd PID #s as an 'odds' input and glob to group the even PID #s as an 'evens' input. I don't think I can use '%08d' on the input as a stream id, because what I'm doing to each packet differs from what I'm doing with the previous packet, as to its destination output file. Perhaps there is some solution using some loop, complex function, counter, or perhaps preferably some 'if' statement, though I'd like it to be done in FFMPEG rather than by the OS using some terminal trickery. I don't know if you can use '|' (backslash pipe) to pipe within FFMPEG (or to execute multiple FFMPEG commands sequentially) independent of the OS/terminal trickery ; (I'm guessing '&&' doesn't work within FFMPEG commands independent of the OS/terminal).

  


  In case it is helpful to know, the TS file is created from an MP4, so perhaps there is some way to transmux so that the packets are getting created in the end sequence needed and then renamed to what they would be if I had just transmuxed from MP4 to TS (though technically I'm transcoding audio [1 or 2 channels] from AAC to AC3 in the transmux step, but the video is h.264 and just copied into the TS file).

  


• How do I change the default path of my homebrew installation ?

  22 février 2021, par Make Perceive

  I'm using both ffmpeg and youtube-dl, installed via homebrew. Mac M1 Apple silicon. They both work fine when I run a command from Terminal, but when I try to run commands via a third party automation script, I'm getting an error and I think it's because the javascript is looking for ffmpeg in the wrong location (something like "opt/bin/youtube-dl" as opposed to "/opt/homebrew/bin/youtube-dl". In this particular example, I think it relies on ffmpeg to do the conversion even though it's using youtube-dl.

  


  I don't know what the best practice is, and in my homebrew install I did see something saying something like "next steps change eval >> path" ; I pasted the line into terminal and ran it but it does not seem to have worked.

  


  Here's an example of the javascript.

  


  
const youtubeDL = '/opt/homebrew/bin/youtube-dl';
var url = 'https://www.youtube.com/watch?v=8YUc5-XaBbI';

log(`Download started`);

var execResult = sf.system.exec({
        commandLine: `"${youtubeDL}" "${url}" --extract-audio --audio-format wav`
    });

log (execResult)

if (execResult.exitCode !== 0) {
    throw `MP4 download failed with exit code: ${execResult.exitCode}`;
}

log('MP4 downloaded');
log (youtubeDL);
log (url);




  


  The error that I'm getting says "ffprobe/avprobe and ffmpeg/avconv not found".

  


• ffmpeg permission denied though the user has permission

  12 octobre 2014, par codename_subho

  I have installed ffmpeg in my server running ubuntu 14. my flask app project root is at /var/www/project/
  i am able to upload files and my python scripts are able to write new files, but when i run ffmpeg in my script it gives permission denied.
  Also running the below line in terminal

  ffmpeg -i path/to/inputfile /path/to/outputfile & ps aux | grep ffmpeg 
  
  
  
  gives the user running the process is "ubuntu" which has write access to the project folder and its subfolders. As i told you other python script run by user "ubuntu" is able to create file.

  permission denied error happens in both cases(python script and directly in terminal)

  update :
  also looking at the confusion with the permissions, is there a way i can run the app from /home/ubuntu/project instead of /var/www/project. i am using mod_wsgi with apache for my flask-app.