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• Transcode to ogg or webm, writing the file as it goes

  22 juillet 2020, par Mark Smith

  I need to transcode files (mp3, flac, m4a and others) to ogg or webm. (This is because I need them to play on Firefox 60.9 which does not support most of these, and flacs are too large. I cannot update the browser.)

  


  ffmpeg can do the transcoding, but when transcoding to ogg or webm, depending on the exact configuration, either 0 bytes or a few kB is written immediately, and then nothing more until the transcoding is complete (even using -flush_packets 1) — hence I cannot start playing the audio.

  


  By comparison, if I transcode to mp3, the file is written progressively and I can start playing immediately.

  


  Is it possible to transcode to ogg or webm in such a way that the file is written as the transcoding happens, and I can start playing it (almost) immediately ?

  


  Configurations I have tried :

  


  ffmpeg -i orig.m4a -c:a libvorbis -flush_packets 1 vorbis.ogg
ffmpeg -i orig.m4a -c:a libopus -flush_packets 1 opus.ogg
ffmpeg -i orig.m4a -c:a libvorbis -flush_packets 1 vorbis.webm
ffmpeg -i orig.m4a -c:a libopus -flush_packets 1 opus.webm


  


  This is running on Debian (Raspian stretch, specifically) and I would like to do it without adding dependencies from outside of the Debian/Raspian archives, if possible. Sticking with ffmpeg would be my ideal choice but will consider others.

  


• Can't link FFmpeg in Visual Studio 2013

  22 février 2016, par Sir DrinksCoffeeALot

  I’m struggling with this for past 3-4 days with barely any progress. I’ve downloaded "dev" and "shared" archives and extracted them. "Dev" archive has .lib and .h files and "Shared" has .dll files needed for running app. These are the steps that i’ve done linking-wise :

  Project -> Properties -> Configuration Properties -> VC++ Directories -> Include Directories -> ...\ dev\ include

  Project -> Properties -> Configuration Properties -> VC++ Directories -> Library Directories -> ...\ dev\ lib

  Project -> Properties -> Configuration Properties -> C/C++ -> General -> Additional Include Directories -> ...\ dev\ include

  Project -> Properties -> Configuration Properties -> Linker -> General -> Additional Library Directories -> ...\ dev\ lib

  Project -> Properties -> Configuration Properties -> Linker -> Input -> Additional Dependencies -> avcodec.lib ... swscale.lib

  And when i try to build it i get following error :

  Error 1 error LNK2019: unresolved external symbol _avcodec_register_all referenced in function _main...

  I have no idea why,somehow .lib are not getting linked or something or i’ve done something wrong. It’s getting really frustrating and ffmpeg is crucial in project that i’m working on, basicly i can’t do anything without it. So please if someone could point me in right direction i would aprreciate it very much.

  This is the example that im trying to build.

  #include 
  
  extern "C"
  
  {
  
  
  
  #include "libavcodec\avcodec.h"
  
  }
  
  
  
  
  
  #pragma comment(lib, "avcodec.lib")
  
  
  
  int main()
  
  {
  
      printf("Trying avcodec_register_all... ");
  
      avcodec_register_all();
  
      printf("Done.\n");
  
      return 0;
  
  }

  Thank you in advance.

• yt-dlp get audio only link -> ffmpeg piped audio -> ffplay

  5 juin 2022, par james28909

  Ok, i have a perl script that i am trying to figure out why it is throwing an io error. First i use yt-dlg to get the link of only the audio - this works as expected and i can navigate to the link in a browser just fine. then i open a ffmpeg pipe in perl and then try to read the output from ffmpeg and eventually, if i can get this working, i will process the ffmpeg output then send to a named pipe.

  


  the problem comes from the ffmpeg when i am processing the data from the link obtained with yt-dlp, and i think it has to do with my while loop but i am not sure what. i have a named pipe called "input". i summon ffmpeg with the following :

  


  #/usr/bin/perl
use strict;
use warnings;

my $file = /path/to/named/pipe
my $read_len = 1024;

open (my $SOURCE_AUDIO, '-|', "ffmpeg -y -i \'$link\' -map 0 -c copy -ac 2 -f opus -ar 48000 pipe:1");
binmode($SOURCE_AUDIO);

# process the ffmpeg output.i have a function i want to implement here, 
# but i need to be able to parse ffmpeg output in set read lengths

while( read($SOURCE_AUDIO, my $buf, $read_len)){
print $file $buf;
};


  


  but before the end of the playback, somewhere around the end of the audio stream ffmpeg throws errors like this :

  


  [tls @ 0x5d0de00] Error in the pull function..2kbits/s speed=1.21x
[tls @ 0x5d0de00] IO error: Connection reset by peer
[tls @ 0x5d0de00] The specified session has been invalidated for some reason.
    Last message repeated 1 times
https://rr3---sn-(truncated): Input/output error
size=    1021kB time=00:01:18.36 bitrate= 106.7kbits/s speed=1.21x
video:0kB audio:1012kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.808163%


  


  i am not sure what is causing it to end early, or what is causing it to be terminated. i can download the file and re-encode it (if needed) and then play it flawlessly with ffplay, but i cannot, for the life of me, parse ffmpeg output and write it to a named pipe. any help sure would be appreciated. thanks

  


  P.S. i am using latest updated windows 11 and WSL's built in perl :

  


  This is perl 5, version 30, subversion 0 (v5.30.0) built for x86_64-linux-gnu-thread-multi
(with 50 registered patches, see perl -V for more detail)

Copyright 1987-2019, Larry Wall

Perl may be copied only under the terms of either the Artistic License or the
GNU General Public License, which may be found in the Perl 5 source kit.

Complete documentation for Perl, including FAQ lists, should be found on
this system using "man perl" or "perldoc perl".  If you have access to the
Internet, point your browser at http://www.perl.org/, the Perl Home Page.