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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.


  


• How to play synchronised multichannel Audio and Video in a C# WPF application ?

  27 mars 2019, par AlexS

  I have video of approximate length 2 mins, and i need to be able to switch between audio streams accompanying the video during playback and even apply varying digital filtering and gain changes to the active audio stream during playback.

  NAudio can cope with the mutlichannel audio, filtering and switching between streams, but there is no support for synchronization with a video.

  How do programmers achieve synchronization, without embedding the audio into the video container directly ?

  Thanks

• What resolution would be best for processing videos in firebase functions ? [closed]

  11 janvier 2020, par Nathan

  I’m making an app that is mainly used for sharing videos of maximum 30 seconds long. One video example could be a screen recording of someone’s computer screen or a game. I have this code that checks whether the uploaded video that has just been uploaded to firebase storage has been processed or not and if it hasn’t then I use ffmpeg to process the video (change the resolution etc.) with this command :

  const promise = spawn('./ffmpeg', ['-i', tempFilePath, '-vf', 'scale=1280:720', targetTempFilePath]);

  Now with these commands, the firebase function is giving me a timeout error when I upload 30 second clips since I’m only converting the video to 720. I was just wondering what compression settings would be sufficient enough for the video to :

  1. Be still a high enough quality in my app
  2. Not take ages processing the video in the function (10-20 second clips works perfectly well).

  I know the better option would be to use Googles App engine or something similar to process videos but I’d prefer it to avoid that at the moment, if I can’t process videos to a good enough quality without sacrificing efficiency then I will go to something like Google’s App engine, just need some advice and some pointers for it otherwise.

  EDIT :

  I’ve seen instagram compresses their videos to a resolution of 640x640 ? Would that be reasonable or is it dependent on the original clip’s resolution ?

  Thanks