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• Convert 2 channel mp4 to each mono wav file using FFMPEG or Python code

  30 mai 2024, par Harish Alwala

  I am new to audio files and its codecs.

  


  I would like to convert a 2 channel mp4 file to a single mono wav files.

  


  My understanding is a when I say 2 channel, it stores speech coming from each microphone in a separate channel. And when I split the channels to each individual mono wav files, I get speech of each microphone.

  


  My intension here is to get the speech from each channel and convert them to text. This way I can set the name of the speaker based on channel.

  


  I tried with ffmpeg and python code as well, unfortunately I get two files with same content.

  


  Looking at the following details
can someone construct ffmpeg command or python script to convert the 2 channel mp4 file to 2 individual mono wav files.

  


  FFprobe
ffprobe -i Two-Channel.mp4 -show_streams -select_streams a

  


  Result

  


  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: isommp42
    encoder         : Google
  Duration: 00:52:42.19, start: 0.000000, bitrate: 421 kb/s
  Stream #0:0[0x1](und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 640x360 [SAR 1:1 DAR 16:9], 322 kb/s, 25 fps, 25 tbr, 12800 tbn (default)
      Metadata:
        handler_name    : ISO Media file produced by Google Inc.
        vendor_id       : [0][0][0][0]
  Stream #0:1[0x2](eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 96 kb/s (default)
      Metadata:
        handler_name    : ISO Media file produced by Google Inc.
        vendor_id       : [0][0][0][0]
[STREAM]
index=1
codec_name=aac
codec_long_name=AAC (Advanced Audio Coding)
profile=LC
codec_type=audio
codec_tag_string=mp4a
codec_tag=0x6134706d
sample_fmt=fltp
sample_rate=44100
channels=2
channel_layout=stereo
bits_per_sample=0
initial_padding=0
id=0x2
r_frame_rate=0/0
avg_frame_rate=0/0
time_base=1/44100
start_pts=0
start_time=0.000000
duration_ts=139452416
duration=3162.186304
bit_rate=96000
max_bit_rate=N/A
bits_per_raw_sample=N/A
nb_frames=136184
nb_read_frames=N/A
nb_read_packets=N/A
extradata_size=16
DISPOSITION:default=1
DISPOSITION:dub=0
DISPOSITION:original=0
DISPOSITION:comment=0
DISPOSITION:lyrics=0
DISPOSITION:karaoke=0
DISPOSITION:forced=0
DISPOSITION:hearing_impaired=0
DISPOSITION:visual_impaired=0
DISPOSITION:clean_effects=0
DISPOSITION:attached_pic=0
DISPOSITION:timed_thumbnails=0
DISPOSITION:non_diegetic=0
DISPOSITION:captions=0
DISPOSITION:descriptions=0
DISPOSITION:metadata=0
DISPOSITION:dependent=0
DISPOSITION:still_image=0
TAG:language=eng
TAG:handler_name=ISO Media file produced by Google Inc.
TAG:vendor_id=[0][0][0][0]
[/STREAM] 


  


  FFmpeg command

  


  ffmpeg -i Two-Channel.mp4 -filter_complex "pan=mono|c0=0c0" left_channel.wav

  


  python code
using FFPMEG I converted mp4 to wav and then tried below code



  


• Why is FFProbe (using fluent-ffmpeg) returning incomplete and inaccurate metadata ?

  18 avril 2024, par volume one

  I am returning metadata about a file using ffprobe. The file can be found here.

  


  I am using fluent-ffmpeg in Node.js which shouldn't make any difference. Its just nicer to use than a command-line.

  


  The code goes like this :

  


  ffmpeg.ffprobe('https://devxxx001.s3.amazonaws.com/vertical-hd_720_1280_30fps.mp4'), function (err, metadata) {
 console.log(JSON.stringify(metadata));
});


  


  The metadata output I receive is this :

  


  {
  "streams": [
    {
      "index": 0,
      "codec_name": "h264",
      "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
      "profile": "High",
      "codec_type": "video",
      "codec_tag_string": "avc1",
      "codec_tag": "0x31637661",
      "width": 720,
      "height": 1280,
      "coded_width": 720,
      "coded_height": 1280,
      "closed_captions": 0,
      "film_grain": 0,
      "has_b_frames": 2,
      "sample_aspect_ratio": "N/A",
      "display_aspect_ratio": "N/A",
      "pix_fmt": "yuv420p",
      "level": 32,
      "color_range": "tv",
      "color_space": "bt709",
      "color_transfer": "bt709",
      "color_primaries": "bt709",
      "chroma_location": "left",
      "field_order": "progressive",
      "refs": 1,
      "is_avc": "true",
      "nal_length_size": 4,
      "id": "0x1",
      "r_frame_rate": "30/1",
      "avg_frame_rate": "30/1",
      "time_base": "1/30",
      "start_pts": 0,
      "start_time": 0,
      "duration_ts": 267,
      "duration": 8.9,
      "bit_rate": 2382497,
      "max_bit_rate": "N/A",
      "bits_per_raw_sample": 8,
      "nb_frames": 267,
      "nb_read_frames": "N/A",
      "nb_read_packets": "N/A",
      "extradata_size": 47,
      "tags": {
        "creation_time": "2020-05-19T10:09:46.000000Z",
        "language": "und",
        "handler_name": "L-SMASH Video Handler",
        "vendor_id": "[0][0][0][0]",
        "encoder": "AVC Coding"
      },
      "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,
        "captions": 0,
        "descriptions": 0,
        "metadata": 0,
        "dependent": 0,
        "still_image": 0
      }
    }
  ],
  "format": {
    "filename": "https:/devxxx001.s3.amazonaws.com/vertical-hd_720_1280_30fps.mp4",
    "nb_streams": 1,
    "nb_programs": 0,
    "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
    "format_long_name": "QuickTime / MOV",
    "start_time": 0,
    "duration": 8.9,
    "size": 2654719,
    "bit_rate": 2386264,
    "probe_score": 100,
    "tags": {
      "major_brand": "mp42",
      "minor_version": "0",
      "compatible_brands": "mp42mp41isomavc1",
      "creation_time": "2020-05-19T10:09:46.000000Z"
    }
  },
  "chapters": []
}


  


  I need to know the aspect ratio of the video so that I can display it properly but ffprobe is returning "N/A" :

  


   "sample_aspect_ratio": "N/A",
 "display_aspect_ratio": "N/A",


  


  In addition, if I want to know the video container format (mp4 in this case), it is showing multiple formats instead of just one :

  


   "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
 "format_long_name": "QuickTime / MOV",


  


  I believe it may be an issue with the ffprobe command but I am unable to pass it options like on the command-line. Even then I don't know what options need to be passed to get the correct metadata.

  


• How to reduce file size of a video without loosing quality using an ffmpeg command ? [closed]

  11 mars 2024, par Shadab Mehdi

  I have received a video that is Full HD 1920 x 1080 and is nearly 62 GB. I know something is off here. I have seen similar videos under 3-4 GB.

  


  I tried to reduce the size by running the following command

  


  ffmpeg -i MyVideo.mpg -vcodec libx265 -crf 28 Compressed.mp4


  


  But it produced horrible out-of-sync audio. The video quality was OK.

  


  Here is a dump of ffprobe video output for better understanding.

  


  ffprobe -v quiet -print_format json -show_format -show_streams -print_format json MyVideo.mpg


  


  The output of the above command produces this response

  


  {
  "streams": [
    {
      "index": 0,
      "codec_name": "mpeg2video",
      "codec_long_name": "MPEG-2 video",
      "profile": "Main",
      "codec_type": "video",
      "codec_tag_string": "[0][0][0][0]",
      "codec_tag": "0x0000",
      "width": 1920,
      "height": 1080,
      "coded_width": 0,
      "coded_height": 0,
      "closed_captions": 0,
      "film_grain": 0,
      "has_b_frames": 1,
      "sample_aspect_ratio": "1:1",
      "display_aspect_ratio": "16:9",
      "pix_fmt": "yuv420p",
      "level": 4,
      "color_range": "tv",
      "chroma_location": "left",
      "field_order": "progressive",
      "refs": 1,
      "id": "0x1e0",
      "r_frame_rate": "25/1",
      "avg_frame_rate": "25/1",
      "time_base": "1/90000",
      "start_pts": 22503,
      "start_time": "0.250033",
      "duration_ts": 643863600,
      "duration": "7154.040000",
      "extradata_size": 150,
      "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,
        "timed_thumbnails": 0,
        "non_diegetic": 0,
        "captions": 0,
        "descriptions": 0,
        "metadata": 0,
        "dependent": 0,
        "still_image": 0
      },
      "side_data_list": [
        {
          "side_data_type": "CPB properties",
          "max_bitrate": 80000000,
          "min_bitrate": 0,
          "avg_bitrate": 0,
          "buffer_size": 9781248,
          "vbv_delay": -1
        }
      ]
    },
    {
      "index": 1,
      "codec_name": "mp2",
      "codec_long_name": "MP2 (MPEG audio layer 2)",
      "codec_type": "audio",
      "codec_tag_string": "[0][0][0][0]",
      "codec_tag": "0x0000",
      "sample_fmt": "s16p",
      "sample_rate": "48000",
      "channels": 2,
      "channel_layout": "stereo",
      "bits_per_sample": 0,
      "initial_padding": 0,
      "id": "0x1c0",
      "r_frame_rate": "0/0",
      "avg_frame_rate": "0/0",
      "time_base": "1/90000",
      "start_pts": 15303,
      "start_time": "0.170033",
      "duration_ts": 643870080,
      "duration": "7154.112000",
      "bit_rate": "384000",
      "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,
        "timed_thumbnails": 0,
        "non_diegetic": 0,
        "captions": 0,
        "descriptions": 0,
        "metadata": 0,
        "dependent": 0,
        "still_image": 0
      }
    }
  ],
  "format": {
    "filename": "MyVideo.mpg",
    "nb_streams": 2,
    "nb_programs": 0,
    "format_name": "mpeg",
    "format_long_name": "MPEG-PS (MPEG-2 Program Stream)",
    "start_time": "0.170033",
    "duration": "7154.120000",
    "size": "62752258052",
    "bit_rate": "70171881",
    "probe_score": 26
  }
}