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• Why can't we find the header file that actually exists ?

  15 décembre 2020, par zhukov18961201

  I am a C language beginners, I encountered a problem, can not find the header file, but in fact, these header files are in the current file, I saw online methods (for example : solution) are to add - I option can solve this problem, but I am very curious, why can't it find itself, can only rely on - I option ?

  


  include path :

  


  ls .
include  test_ffmpeg.c
ls include/libavcodec/
avcodec.h  avfft.h    dirac.h       dxva2.h  vaapi.h  vdpau.h    videotoolbox.h   xvmc.h
avdct.h    d3d11va.h  dv_profile.h  qsv.h    vda.h    version.h  vorbis_parser.h


  


  source tree :

  


  root
 |-----test_ffmpeg.c 
 |-----include 
      


  


  code :

  


  #include 

#include "./include/libavcode/avcodec.h"
#include "./include/libvformat/acfomat.h"
#include "./include/libavfilter/avfilter.h"

int main(void)
{

    return 0;
}


  


  compile :

  


  gcc test_ffmpeg.c  -lavcodec -lavdevice -lavfilter -lavformat -lavutil


  


  a fatal error occured :

  


  test_ffmpeg.c:3:10: fatal error: ./include/libavcode/avcodec.h: No such file or directory
#include "./include/libavcode/avcodec.h"
      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.


  


• In ffmpeg command-line, how to show all filter settings and their parameters before encoding ?

  7 décembre 2023, par F.X.

  Is there a way to force the ffmpeg command-line to display a comprehensive list of all filters and their parameters, even those that are applied automatically like -vf scale ?

  


  (EDIT : To clarify, I do not mean filter documentation, but rather displaying filters that are instantiated at runtime for a particular command-line, just before transcoding starts. The goal of this is mostly checking that ffmpeg is indeed doing the right thing and not inserting/changing filters when I do not intend it to.)

  


  There are a few options available, but none are comprehensive enough. For example :

  


  

  • The lavfi module has a dumpgraph option (here) but only if you're using lavfi.

  


  • The -sws_flags print_info option (here) can be used to determine if -vf scale is applied automatically and shows a subset of its parameters, but not all of them.

  


  


  Additionally, this question appears related the answer doesn't answer what I'm looking for.

  


  Are there better ways to achieve that ?

  


• I can't get any error messages on node.js spawn, using ffmpeg

  21 mars 2021, par rickster26ter1

  I am trying to get the errors from a spawn process on nodejs, trying to run FFMPEG. I have not run a child process before explicitly, so I'm not sure this is right, but what I have gathered from code examples online :

  


      const {spawn} = require('child_process');
    async function(req,res){
           
    console.log(res.req.files.data[0].path);
    var tst_loc = res.req.files.data[0].path;
    try {
            var the_arr = tst_loc.split('/');
            the_arr.pop();
            tst_loc1 = the_arr.join('/') +"/test.avi";
            console.log("HERE");
            var cmd = 'ffmpeg';
                var tstspawn = spawn(cmd, [
                '-i', tst_loc,
                '-s', '800x400',
                '-b:v', '64k',
                '-c:v', 'avi',
                '-c:a', tst_loc1,
                '-o', outputfilename
            ], (error, stdout, stderr) => {
                  if (error) {
                      console.error('Error!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!:', stderr);
                      throw error;
                  }
                  console.log('Success!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!', stdout);
            })
            
            tstspawn.stderr.on('data', function(data) {
            //Here is where the error output goes

               console.log('stderr: ' + data);

               data=data.toString();
               scriptOutput+=data;
            });
       

 
            tstspawn.stderr.on('error',function(error){
              console.log(error);
            });

  } catch (e) {
    console.log(e.code);
    console.log(e.msg);
  }


  


  Returns only my console logs of the path data, the console log of the "HERE", and nothing else at all. I know it didn't run properly because I do not get the expected video file that FFMPEG should have output. But I can't get any sort of error message on my console. No crashing of the application or anything...

  


  Thanks for any help,