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• Proprietary codecs on Linux. What is legal ?

  17 octobre 2016, par George Eco

  So, assuming we got a distribution without proprietary codecs installed.
  Let’s take Linux Mint for example. I want to store and playback wav and ogg format sounds, either by using my own software, or by using another developer’s software. So far so good right ?

  Imagine now that we have the following scenario. For some reason, I wanna playback a file that is either an mp4 or mp3 or mpeg or any other format, made by proprietary codecs. Instantly, I will need a codec for these formats.

  I read somewhere that Fluendo sells solutions for "legal codec usage" for linux distros.
  URL of fluendo : http://www.fluendo.com/en/

  So here comes the questions :

  Using VLC and ffmpeg is enough for me to convert a file to an ogg or ogv so I can playback a song or a video using an open format. You can also playback playback files made by proprietary formats. But are VLC and ffmpeg legal to use, to playback such files made by proprietary codecs ? For example, ss VLC codecs okay to be used without paying anyone for mp4 playback ? Is it okay to convert a file from mp4 to ogv ?
  If not, are there any legal and open source and free (as in freedom) codecs around that can solve the issue, or does someone have to pay a product, to be ethically correct, to the developers of the proprietaty codecs ?

  Note that I do not ask for Windows, since codec licenses are included to the price of the operating system. I ask exclusively for a free linux distribution.

• avcodec/iff : Split extract_header into extradata and packet part

  11 juillet 2022, par Andreas Rheinhardt

  avcodec/iff : Split extract_header into extradata and packet part
  183132872a1d8bc8a32e7fd8f994fa2f1b2d6bfc made the iff demuxer
  
  output extradata and made the decoder parse said extradata.
  
  To make this extradata extensible, it came with its own internal
  
  length field (containing the offset of the palette at the end
  
  of the extradata). Furthermore, in order to support mid-stream
  
  extradata changes, the packets returned by the demuxer also have
  
  such a length field (containing the offset of the actual packet
  
  data). Therefore the packet parsing the extradata accepted its
  
  input from both AVPackets as well as from ordinary extradata.
  Yet the demuxer never made use of this "feature" : The packet's
  
  length field always indicated that the packet data starts
  
  immediately after the length field.
  Later, commit cb928fc448f9566e6f6c28d53fa4c2388e732a2b stopped
  
  appending the length field to the packets' data ; of course,
  
  it also stopped searching for extradata in this data.
  Instead it added code to parse the packet's header to the function
  
  that parses extradata. This made this function consist of two disjoint
  
  parts, one of which is only reachable if this function is called
  
  from init (when parsing extradata) and one of which is reachable
  
  when parsing packet headers.
  Therefore this commit splits this function into two.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/iff.c

• Slice a long video with ffmpeg to little pieces in node js

  24 janvier 2018, par ler

  I have a very big video like 3 hours, and I want to slice it to little pieces of 20 minutes each.
  This is my initial code :

  var fs = require('fs'); 
  
  var spawn = require('child_process').spawn;
  
  var ffmpeg = spawn("ffmpeg", [
  
      '-i', './videos/long-video.mp4',
  
      '-codec:v', 'copy', 
  
      '-codec:a', 'copy', 
  
      '-f','mp4',
  
      '-map', '0', '-f', 'segment', '-segment_time', '1200', './videos/pieces/video_%04d.mp4'
  
    ]); 

  What this code do is slice the video in pieces and save them to the location I provided, so you need to wait until the ffmpeg finish slicing the whole video.
  But what I’m looking for is a way to trigger a code when ever ffmpeg has made a new piece so I can insert the video name in database, something like this :

  var fs = require('fs'); 
  
  var spawn = require('child_process').spawn;
  
  var ffmpeg = spawn("ffmpeg", [
  
      '-i', './videos/long-video.mp4',
  
      '-codec:v', 'copy', 
  
      '-codec:a', 'copy', 
  
      '-f','mp4',
  
      '-map', '0', '-f', 'segment', '-segment_time', '1200', 
  
      'pipe:1'
  
    ]);
  
  ffmpeg.stdout.on('data', function (data) {
  
      // store the video name in database
  
      console.log('new peice has been made' );
  
    });
  
  ffmpeg.stderr.on('data', function (data) {
  
      console.log('error' );
  
    });

  ffmpeg.stdout.on doesn’t exit I just made it to indicate what I’m looking for. What does exist is ffmpeg.stdout.pipe() ; but again I don’t know how to trigger a code whenever a new piece has been made.