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• FFMPEG avformat_open_input returns unpopulated Format context

  21 avril 2013, par Michael IV

  I am trying to load avi and flv files programatically with FFMPEG API.The files seem to get loaded because avformat_open_input doesn't return 0 .But when inspecting AVFormatContext variable for every property in the inspector I am getting just "Unable to read memory" .Here is how I do it :

              av_register_all();
  
      avcodec_register_all();
  
      AVFormatContext *pFormatCtx=avformat_alloc_context();
  
  
  
  
  
      if(avformat_open_input(&pFormatCtx,"assest/comp1.avi",NULL,NULL) !=0)
  
      {
  
  
  
          printf("%s","Movie load Success");
  
      }else{
  
  
  
  
  
          printf("%s","Movie load Fail");
  
      }   

  I am using VisualStudio 2010 C++ compiler .Windows 7.

  UPDATE :

  Ok ,Please discard this question.I found the error.It was a stupid typo in the file directory path.

• Popen.communicate() returns only err when running ffmpeg

  17 février 2013, par Jan Pulpan

  I'm trying to run ffmpeg from python and get some reasonable output. Doesn't matter what ffmpeg's log level is set, the only output I get from Popen.communicate() is err one. The content isn't an error however. I tried the same code to run other commands (ls) and it seems to be Ok with both out and err outputs.

  I checked here and Google and unfortunately found nothing. Most of the examples use os or commands modules, not subprocess.

  This is my test code :

  command = [
  
          'ffmpeg',
  
          '-v', 'debug',
  
          '-i', '1.mov',
  
          '-vcodec', 'libx264',
  
          '-profile:v', 'high',
  
          '-preset', 'slower',
  
          '-b:v', '1000k',
  
          '-vf', 'scale=-1:720',
  
          '-threads', '0', 
  
          '-acodec', 'libfdk_aac',
  
          '-b:a', '192k',
  
          '-y',   
  
          '2.mp4',
  
          ]
  
  p = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
  
  out, err =  p.communicate()
  
  f = open('out.log', 'w')
  
  f.write(out)
  
  f.close()
  
  f = open('error.log', 'w')
  
  f.write(err)
  
  f.close()

  Have you ever see something like this ? Am I doing any mistakes or is there an bug in ffmpeg ?

• ffprobe returns mov,mp4,m4a,3gp,3g2,mj2

  19 octobre 2015, par sathia

  I’m trying to find a certain way to understand if a given file is using the h.264 codec and it’s streamable.

  I’m using ffprobe and sometimes I get output such as this :

  {
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'file.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 512
  
      compatible_brands: isomiso2avc1mp41
  
      creation_time   : 2036-02-06 06:28:16
  
      encoder         : HandBrake 0.10.2 2015060900
  
    Duration: 00:06:42.13, start: 0.000000, bitrate: 950 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709), 640x480 [SAR 1:1 DAR 4:3], 788 kb/s, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
  
      Metadata:
  
        creation_time   : 2036-02-06 06:28:16
  
        handler_name    : VideoHandler
  
      Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 155 kb/s (default)
  
      Metadata:
  
        creation_time   : 2036-02-06 06:28:16
  
        handler_name    : Stereo
  
      "format": {
  
          "filename": "file.mp4",
  
          "nb_streams": 2,
  
          "nb_programs": 0,
  
          "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
  
          "format_long_name": "QuickTime / MOV",
  
          "start_time": "0.000000",
  
          "duration": "402.134000",
  
          "size": "47787790",
  
          "bit_rate": "950683",
  
          "probe_score": 100,
  
          "tags": {
  
              "major_brand": "mp42",
  
              "minor_version": "512",
  
              "compatible_brands": "isomiso2avc1mp41",
  
              "creation_time": "2036-02-06 06:28:16",
  
              "encoder": "HandBrake 0.10.2 2015060900"
  
          }
  
      }
  
  }

  now, it seems that the file is streamable and it’s ok to be put online, but I was expecting something like this :

      "format_name": "h.264",

  instead I get

      "format_name": "mov,mp4,m4a,3gp,3g2,mj2",

  which seems very lax in terms of specifying what the hell this file is.
  I’m also using MP4Box in order to see if the video is streamable, but at this point I’m not sure how to handle specific h.264 recognition.

  what should I do in order to be sure that a given file has the h.264 codec ?

  thanks