Recherche avancée

Sur d’autres sites (6111)

• How to determine webm duration using ffprobe

  23 août 2021, par Lopakhin

  My goal is simple , I have several webm files need to be concated, but first I need to determine their durations.

  



  It seems webm file are played as streams, so there is no way to tell the length of each file.

  



  I have been using ffprobe to do the job ,but the duration returned is N/A.The command I use was :

  



  ffprobe -i input.file -show_format | grep duration


  



  thanks.

  



  The complete output of ffprobe list below :

  



   ffprobe version 2.6.2 Copyright (c) 2007-2015 the FFmpeg developers
  built with Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/2.6.2 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-libxvid --enable-libtheora --enable-libvorbis --enable-libvpx --enable-vda
  libavutil      54. 20.100 / 54. 20.100
  libavcodec     56. 26.100 / 56. 26.100
  libavformat    56. 25.101 / 56. 25.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 11.102 /  5. 11.102
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  1.100 /  1.  1.100
  libpostproc    53.  3.100 / 53.  3.100
Input #0, matroska,webm, from '231':
  Metadata:
    encoder         : GStreamer matroskamux version 1.5.91
    creation_time   : 2015-12-05 07:59:29
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0(eng): Video: vp8, yuv420p, 640x480, SAR 1:1 DAR 4:3, 14.99 fps, 14.99 tbr, 1k tbn, 1k tbc (default)
    Metadata:
      title           : Video
    Stream #0:1(eng): Audio: vorbis, 48000 Hz, stereo, fltp (default)
    Metadata:
      title           : Audio
duration=N/A


  


• How does ffprobe determine duration ?

  10 janvier 2019, par jasongullickson

  I’m using ffprobe to analyze media files stored on a remote server. This seems to work well, but for some files the duration is missing or incorrect (usually longer than it should be). Other times it returns this information accurately, and it doesn’t seem to be related to the media type (codec, etc.).

  Here’s an example of a command that works :

  ffprobe -v quiet -print_format json -show_streams -show_format http://host.com/file.aiff

  {
  
  "streams": [
  
      {
  
          "index": 0,
  
          "codec_name": "pcm_s16be",
  
          "codec_long_name": "PCM signed 16-bit big-endian",
  
          "codec_type": "audio",
  
          "codec_time_base": "1/44100",
  
          "codec_tag_string": "[0][0][0][0]",
  
          "codec_tag": "0x0000",
  
          "sample_fmt": "s16",
  
          "sample_rate": "44100",
  
          "channels": 2,
  
          "bits_per_sample": 16,
  
          "r_frame_rate": "0/0",
  
          "avg_frame_rate": "0/0",
  
          "time_base": "1/44100",
  
          "start_pts": 0,
  
          "start_time": "0.000000",
  
          "duration_ts": 8494248,
  
          "duration": "192.613333",
  
          "bit_rate": "1411200",
  
          "nb_frames": "8494248",
  
          "disposition": {
  
              "default": 0,
  
              "dub": 0,
  
              "original": 0,
  
              "comment": 0,
  
              "lyrics": 0,
  
              "karaoke": 0,
  
              "forced": 0,
  
              "hearing_impaired": 0,
  
              "visual_impaired": 0,
  
              "clean_effects": 0,
  
              "attached_pic": 0
  
          }
  
      }
  
  ],
  
  "format": {
  
      "filename": "http://host.com/file.aiff",
  
      "nb_streams": 1,
  
      "nb_programs": 0,
  
      "format_name": "aiff",
  
      "format_long_name": "Audio IFF",
  
      "start_time": "0.000000",
  
      "duration": "192.613333",
  
      "probe_score": 100
  
  }
  
  }

  Here’s an example of one that doesn’t :

  ffprobe -v quiet -print_format json -show_streams -show_format "http://host.com/file.wav"

  Which generates this result :

  {
  
  "streams": [
  
      {
  
          "index": 0,
  
          "codec_name": "pcm_s16le",
  
          "codec_long_name": "PCM signed 16-bit little-endian",
  
          "codec_type": "audio",
  
          "codec_time_base": "1/44100",
  
          "codec_tag_string": "[1][0][0][0]",
  
          "codec_tag": "0x0001",
  
          "sample_fmt": "s16",
  
          "sample_rate": "44100",
  
          "channels": 2,
  
          "bits_per_sample": 16,
  
          "r_frame_rate": "0/0",
  
          "avg_frame_rate": "0/0",
  
          "time_base": "1/44100",
  
          "bit_rate": "1411200",
  
          "disposition": {
  
              "default": 0,
  
              "dub": 0,
  
              "original": 0,
  
              "comment": 0,
  
              "lyrics": 0,
  
              "karaoke": 0,
  
              "forced": 0,
  
              "hearing_impaired": 0,
  
              "visual_impaired": 0,
  
              "clean_effects": 0,
  
              "attached_pic": 0
  
          }
  
      }
  
  ],
  
  "format": {
  
      "filename": "http://host.com/file.wav",
  
      "nb_streams": 1,
  
      "nb_programs": 0,
  
      "format_name": "wav",
  
      "format_long_name": "WAV / WAVE (Waveform Audio)",
  
      "bit_rate": "1411200",
  
      "probe_score": 99
  
  }
  
  }

  These two examples are different formats, but I’ve seen it work and not work when the format is the same, I just don’t have an example handy.

  What I’d like to know is if there is something I can change about the parameters I’m using with ffprobe to allow the duration to be determined consistently and accurate, or any information I can find as to how ffprobe works so I figure out how I might change the input files, etc. so they work correctly.

  Alternatively, if there is a different tool that works more reliably (it would need to be an open-source Linux tool) any suggestions or recommendations are welcome.

• How to determine how much of a video stream buffer is filled ?

  17 août 2018, par jjulianf

  On my Ubuntu machine, I am encoding a video with the x265 codec using ffmpeg.
  Then I want to stream the video from a server to a client.

  Since the available bandwidth is limited in specific scenarios, I want to observe the moment when the transmission is starting to stutter.

  Therefore I want to compare the amount of data being sent at this scenario with the amount of data which is already stored in the buffer (and which was sent a few frames earlier) at the client’s side.

  Is there any way to determine how much data is stored in the buffer of the decoding client ? Maybe some ffmpeg command for it ?

  Since I am playing the stream with the VLC player at the client side, is there a vlc-CLI-command to check the buffer status ?

  It would be perfect if I could get the current fill of the buffer for every second so that I can graph it like this :