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• ffplay does not exit in forked child

  6 septembre 2019, par user12030145

  ffplay  -autoexit does not exit in a forked child

  I need to pipe my application (stdout) to ffplay (stdin). I do this by forking ffplay as a child and using -i pipe:0 as argument.

  #include 
  
  #include 
  
  #include <sys></sys>types.h>
  
  #include <sys></sys>wait.h>
  
  
  
  int main(int argc, const char** argv)
  
  {
  
  int tube[2];
  
  int c;
  
  FILE* f = fopen(argv[1], "rb");
  
  pid_t pid;
  
  if (argc &lt; 2) return -1;
  
  if (pipe(tube))  {
  
      perror("Pipe");
  
      return -1;
  
    }
  
  
  
  // main process cats a .mlp file to stdout, sent to a child ffplay stdin through a pipe
  
  char* const arg[] = {"-i", "pipe:0", "-f", "mlp", "-nodisp", "-autoexit", NULL};
  
  switch (pid = fork())    {
  
              case -1:
  
                  fprintf(stderr,"%s\n", "Could not launch ffplay");
  
                  break;
  
  
  
              case 0:
  
                  close(tube[1]);
  
                  dup2(tube[0], STDIN_FILENO);
  
                  execv("/usr/bin/ffplay", arg);
  
                  fprintf(stderr, "%s\n", "Runtime failure in ffplay child process");
  
                  return -2;
  
  
  
              default:
  
                  close(tube[0]);
  
                  dup2(tube[1], STDOUT_FILENO);
  
          }
  
  
  
  // Here the main process code sending the .mlp file to stdout...
  
  
  
  while ((c = fgetc(f)) != EOF) putchar(c);
  
  
  
  waitpid(pid, NULL, 0);
  
  fclose(f);
  
  
  
  // main never returns
  
  return 0;
  
  }

  The issue is that in this context, ffplay -autoexit never exits (GNU-Linux platform). In a main process, ffplay -autoexit always exits at the end of a media file.
  Is there a pure C workaround without using system, popen or scripting ?
  Is this a feature or a bug of ffplay (I cannot tell) ?

• youtube-dl doesn't see ffmpeg in the executable

  30 novembre 2019, par Михаил Муратов

  I am writing a program to download music and videos via youtube-dl in python. Next, I pack the script into an executable file via pyinstaller.

  The problem is that youtube-dl (in the executable) doesn’t see ffmpeg and ffprobe, even though I add them to the spec file.

  As far as I know youtube-dl has the ffmpeg_location parameter, but that’s only in the console version. Maybe it is also for python ? But I didn’t find any information about it.

  How do I solve the problem ?

  ---

  command to create executable :

  pyinstaller --upx-dir=c:\users\exe-builder c:\users\exe-builder\youtubedownloader\main.spec

  .spec file :

  # -*- mode: python -*
  
  block_cipher = None
  
  
  
  a = Analysis(['C:\\Users\\Exe-Builder\\YoutubeDownloader\\main.py'],
  
               pathex=['C:\\Users\\Exe-Builder\\YoutubeDownloader'],
  
               binaries=[],
  
               datas=[],
  
               hiddenimports=[],
  
               hookspath=[],
  
               runtime_hooks=[],
  
               excludes=[],
  
               win_no_prefer_redirects=False,
  
               win_private_assemblies=False,
  
               cipher=block_cipher,
  
               noarchive=False)
  
  
  
  a.binaries += [('ffmpeg.exe','C:\\Users\\Exe-Builder\\YoutubeDownloader\\ffmpeg.exe', "Binary"),
  
                 ('ffprobe.exe','C:\\Users\\Exe-Builder\\YoutubeDownloader\\ffprobe.exe', "Binary")]
  
  
  
  pyz = PYZ(a.pure, a.zipped_data,
  
               cipher=block_cipher)
  
  exe = EXE(pyz,
  
            a.scripts,
  
            a.binaries,
  
            a.zipfiles,
  
            a.datas,
  
            [],
  
            name='MediaDownloader',
  
            debug=False,
  
            bootloader_ignore_signals=False,
  
            strip=False,
  
            upx=True,
  
            upx_exclude=['vcruntime140.dll'],
  
            runtime_tmpdir=None,
  
            console=True)

  very small example :

  import youtube_dl
  
  
  
  url = 'https://www.youtube.com/watch?v=MIk55C1s0ns'
  
  outtmpl = '\\%(title)s.%(ext)s'
  
  ydl_opts = {'format': 'bestaudio/best',
  
              'outtmpl': outtmpl,
  
              'postprocessors': [{'key': 'FFmpegExtractAudio', 
  
                                  'preferredcodec': 'mp3',
  
                                  'preferredquality': '128'}]}
  
  
  
  with youtube_dl.YoutubeDL(ydl_opts) as ydl:
  
      info_dict = ydl.extract_info(url, download=True)

  error message :

  youtube_dl.utils.DownloadError: ERROR: ffprobe/avprobe and ffmpeg/avconv not found. Please install one.

• converting complex ffmpeg command to python3

  14 janvier 2020, par Martin

  I have a complicated ffmpeg command that takes audio and image as input, and exports a music video.

  ffmpeg -loop 1 -framerate 2 -i "front.png" -i "testWAVfile.wav" \
  
      -vf "scale=2*trunc(iw/2):2*trunc(ih/2),setsar=1,format=yuv420p" \
  
      -c:v libx264 -preset medium -tune stillimage \
  
      -crf 18 -c:a aac -shortest -vf scale=1920:1080  "outputVideo.mp4"

  I’m trying to write a python3 program cmdMusicVideo.py which will run this command in pure Python. I know that to run this command you need the ffmpeg program, I’m trying to write it in pure python3, where I’m not just spawning a separate process to run the bash command where the user needs to have ffmpeg installed.

  I’ve looked at the various solutions to running ffmpeg in python3, and they’re either :

  • A : Just running the ffmpeg command as a subprocess, where the user needs to have ffmpeg installed
  • or B : An ffmpeg pip program like ffmpeg-python

  The pip libraries I’ve checkout out all use incredibly different formatting, and I haven’t found a way to replicate my ffmpeg command. I’ve searched the loop command in their python package documentation and it doesn’t appear anywhere.

  Is there a way to convert my ffmpeg command into a python3 program where the user doesn’t need to already have ffmpeg installed on their computer ?

  The plan is to eventually turn this into its own pip package, and my concern is that if I use the A method, there would be a case where somebody tries to run my pip command but doesn’t have ffmpeg installed on their terminal (maybe using a python3 specific terminal ?)