Recherche avancée

Sur d’autres sites (9002)

• What is the difference between these 2 videos ?

  8 octobre 2018, par 98mprice

  I am using fluent-ffmpeg to resize a video.

  I can’t figure out what’s happening though. I have 2 video files, one works but the other doesn’t. I’ve been scouring the mediainfo outputs of both files, checking for discrepancies but other than filesize, duration etc. there’s no difference (same codec, format, width/height, frame rate etc)

  Here’s a link to both files.

  I’ve been reading these video files into fluent-ffmpeg using an input stream, as so :

  await new Promise((resolve, reject) => {
  
      ffmpeg(file.stream)
  
        .output(path)
  
        .size('426x240')
  
        .on('start', function() {
  
            console.log('started');
  
        })
  
        .on('error', function(err) {
  
            console.log('An error occurred: ' + err.message);
  
        })
  
        .on('progress', function(progress) {
  
            console.log('... frames: ' + progress.frames);
  
        })
  
        .on('end', function() {
  
          console.log('Finished processing');
  
          resolve();
  
        })
  
        .run();
  
  });

  The working file prints :

  started
  
  ... frames: 86
  
  ... frames: 107
  
  Finished processing

  But the non-working file doesn’t seem to have any frames, and prints :

  started
  
  ... frames: 0
  
  Finished processing

  Any idea what could be wrong ?

  The ffmpeg command being executed :

  ffmpeg -i pipe:0 -y -filter:v scale=w=426:h=240 uploads/works.mp4

• What is the difference between these 2 wav files ?

  14 août 2018, par user2276831

  I am trying to use a program called arss to create a spectrogram from a wav file. I have 2 wav files, one works and the other does not (it was converted to wav from mp3).

  The error that arss throws at me is This WAVE file is not currently supported. Which is fine, but I have no idea what parts of my wav file to change so that it will be supported. The docs don’t help here (as far as I can tell)

  When I run mediainfo on both wav files, I can the following specs :

  working wav :

  General
  
  Complete name                            : working.wav
  
  Format                                   : Wave
  
  File size                                : 1.15 MiB
  
  Duration                                 : 6 s 306 ms
  
  Overall bit rate mode                    : Constant
  
  Overall bit rate                         : 1 536 kb/s
  
  
  
  Audio
  
  Format                                   : PCM
  
  Format settings                          : Little / Signed
  
  Codec ID                                 : 1
  
  Duration                                 : 6 s 306 ms
  
  Bit rate mode                            : Constant
  
  Bit rate                                 : 1 536 kb/s
  
  Channel(s)                               : 2 channels
  
  Sampling rate                            : 48.0 kHz
  
  Bit depth                                : 16 bits
  
  Stream size                              : 1.15 MiB (100%)

  not working wav :

  General
  
  Complete name                            : not_working.wav
  
  Format                                   : Wave
  
  File size                                : 5.49 MiB
  
  Duration                                 : 30 s 0 ms
  
  Overall bit rate mode                    : Constant
  
  Overall bit rate                         : 1 536 kb/s
  
  Writing application                      : Lavf57.83.100
  
  
  
  Audio
  
  Format                                   : PCM
  
  Format settings                          : Little / Signed
  
  Codec ID                                 : 1
  
  Duration                                 : 30 s 0 ms
  
  Bit rate mode                            : Constant
  
  Bit rate                                 : 1 536 kb/s
  
  Channel(s)                               : 2 channels
  
  Sampling rate                            : 48.0 kHz
  
  Bit depth                                : 16 bits
  
  Stream size                              : 5.49 MiB (100%)

  Comparing the audio specs of both files, I can’t tell any difference between anything other than the file size and duration. I even updated the Sampling rate of the non-working wav using ffmpeg so that it would match the working one at 48.0kHz, but no luck.

  Any idea ?

  Both wav files are avaliable here

• Difference between 'display_aspect_ratio' and 'sample_aspect_ratio' in ffprobe [duplicate]

  18 juin 2018, par John Allard

  This question already has an answer here :

  • ffmpeg scaling not working for video
    
    1 answer
    

  I have an issue where a video is played in the correct 16:9 aspect ratio when played through VLC or quicktime player, but when I attempt to extract individual frames with ffmpeg the frames come out as 4:3 aspect ratio.

  The ffprobe output on the video in question is as follows

  $ ffprobe -v error -select_streams v:0 -show_entries stream -of default=noprint_wrappers=1 -print_format json movie.mp4
  
  
  
  {
  
  "programs": [
  
  
  
  ],
  
  "streams": [
  
      {
  
          "index": 0,
  
          "codec_name": "h264",
  
          "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
  
          "profile": "Main",
  
          "codec_type": "video",
  
          "codec_time_base": "126669/6400000",
  
          "codec_tag_string": "avc1",
  
          "codec_tag": "0x31637661",
  
          "width": 2592,
  
          "height": 1944,
  
          "coded_width": 2592,
  
          "coded_height": 1944,
  
          "has_b_frames": 0,
  
          "sample_aspect_ratio": "4:3",
  
          "display_aspect_ratio": "16:9",
  
          "pix_fmt": "yuvj420p",
  
          "level": 50,
  
          "color_range": "pc",
  
          "color_space": "bt709",
  
          "color_transfer": "bt709",
  
          "color_primaries": "bt709",
  
          "chroma_location": "left",
  
          "refs": 1,
  
          "is_avc": "true",
  
          "nal_length_size": "4",
  
          "r_frame_rate": "25/1",
  
          "avg_frame_rate": "3200000/126669",
  
          "time_base": "1/12800",
  
          "start_pts": 0,
  
          "start_time": "0.000000",
  
          "duration_ts": 126682,
  
          "duration": "9.897031",
  
          "bit_rate": "4638928",
  
          "bits_per_raw_sample": "8",
  
          "nb_frames": "250",
  
          "disposition": {
  
              "default": 1,
  
              "dub": 0,
  
              "original": 0,
  
              "comment": 0,
  
              "lyrics": 0,
  
              "karaoke": 0,
  
              "forced": 0,
  
              "hearing_impaired": 0,
  
              "visual_impaired": 0,
  
              "clean_effects": 0,
  
              "attached_pic": 0,
  
              "timed_thumbnails": 0
  
          },
  
          "tags": {
  
              "language": "und",
  
              "handler_name": "VideoHandler"
  
          }
  
      }
  
  ]
  
  }

  So it says

      "width": 2592,
  
      "height": 1944,
  
      "coded_width": 2592,
  
      "coded_height": 1944,
  
      "has_b_frames": 0,
  
      "sample_aspect_ratio": "4:3",
  
      "display_aspect_ratio": "16:9",

  which seems odd to me. The width/height are in 4:3, the sample aspect ratio is 4:3, the display is 16:9 ?

  Now, when I play this through VLC/Quicktime the video looks fine (screenshot below)

  

  but now, if I run an ffmpeg command to extract individual frames from this video, they come out in 4:3

  ffmpeg -y -hide_banner -nostats -loglevel error -i movie.mp4 -vf select='eq(n\,10)+eq(n\,20)+eq(n\,30)+eq(n\,40)',scale=-1:640 -vsync 0 /tmp/ffmpeg_image_%04d.jpg

  

  So I guess my questions are as follows :

  1. what is the relation between display aspect ratio, sample aspect ratio, and the width/height ratio ?
  2. how to I get ffmpeg to output in the correct aspect ratio ?