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• What is ffprobe metadata "programs" ?

  27 août 2020, par nonayme

  All in the topic : what are "progams" in context of video ?

  


  As you may expect, any google lookup containg "programs" yield many irrelevant results... no matter search tricks you can apply.

  


  I tried some general search about video metadata, found a glossary about digital & multimedia, and also a search engine about metadata but didnt get anything.

  


  In the ffprobe doc it seems to be sort of the container, but what is its use ?

  


  thanks for any reply which lift this fog ^^

  


• looping a ffmpeg command that joins two files

  27 octobre 2020, par user3428634

  Command ffmpeg -i file-1.mp4 -vf ass=file-1a.ass burned-1.mp4

  


  works to burn file-1a.ass subtitles on file-1.mp4 video.

  


  But each time I have to reiterate the same command on over 40 different videos and subtitles and each time I have to wait for rendering the output.

  


  So perhaps there is a way to automatically reiterate the same command on all the files.

  


  Looking for a reply found the loop command
for f in *; do ffmpeg $f;

  


  But I am confused how to use it with 2 files, the .mp4 and the .ass file, and also the output file which should have the same number

  


  I imagine should put the same name on each couple of files, such as :
1.mp4 1.ass
2.mp4 2.ass
3.mp4 3.ass
etc

  


  and then
for f in *; do ffmpeg -i $f.mp4 -vf ass=$f.ass $f-output.mp4

  


  But I have no clear idea

  


• VLC snytax to transcode & stream to stdout ?

  4 octobre 2016, par Will Tower

  Goal : I am trying to use VLC as a local server to expand the video capabilities of an app created with Adobe AIR, Flex and Actionscript. I am using VLC to stream to stdoutand reading that output from within my app.

  VLC Streaming capabilities
  VLC Flash Video

  Status : I am able to launch VLC as a background process and control it through its remote control interface (more detail). I can load, transcode and stream a local video file. The example app below is a barebones testbed demonstrating this.

  Issue : I am getting data in to my app but it is not rendering as video. I don’t know if it is a problem with my VLC commands or with writing to/reading from stdout. This technique of reading from stdout in AIR works (with ffmpeg for example).

  One of the various transcoding commands I have tried :

  -I rc  // remote control interface  
  
  -vvv   // verbose debuging  
  
  --sout  // transcode, stream to stdout 
  
  "#transcode{vcodec=FLV1}:std{access=file,mux=ffmpeg{mux=flv},dst=-}"

  This results in data coming into to my app but for some reason it is not rendering as video when using appendBytes with the NetStream instance.

  If instead I write the data to an .flv file, a valid file is created – so the broken part seems to be writing it to stdout. One thing I have noticed : I am not getting metadata through the stdout`method. If I play the file created with the command below, I do see metadata.

  Hoping someone sees where I am going wrong here.

  ---

  // writing to a file
  
  var output:File = File.desktopDirectory.resolvePath("stream.flv");
  
  var outputPath:String = output.nativePath;
  
  "#transcode{vcodec=FLV1}:std{access=file,mux=ffmpeg{mux=flv},dst=" + outputPath + "}");

  ---

  Note : In order to get this to work in AIR, you need to define the app profile as "extendedDesktop"

  ---

    <?xml version="1.0" encoding="utf-8"?>