title: isolate the output only: FFmpeg
body: <p>I'm trying to isolate the value given by ffmpeg when running a command.</p>
  
  <p>The command is:</p>
  
  <pre><code>ffmpeg -i 03.mxf -c:v copy -c:a pcm_s24le -hide_banner -nostats -af loudnorm=I=-23:TP=-2:LRA=7:print_format=json -f null -
  </code></pre>
  
  <p>I only want the JSON text:</p>
  
  <pre><code>{
          "input_i" : "-19.90",
          "input_tp" : "-1.69",
          "input_lra" : "2.40",
          "input_thresh" : "-30.39",
          "output_i" : "-23.28",
          "output_tp" : "-5.06",
          "output_lra" : "0.40",
          "output_thresh" : "-33.59",
          "normalization_type" : "dynamic",
          "target_offset" : "0.28"
  }
  </code></pre>
  
  <p>However, </p>
  
  <p>The output is:</p>
  
  <pre><code>Guessed Channel Layout for Input Stream #0.1 : mono
  Guessed Channel Layout for Input Stream #0.2 : mono
  Input #0, mxf, from 'D:\Abul\Documents\Projects\IngestQC\Source_Folder\IRO_ROKDSTV_10s_PRO_Valentines2018_Ident_002_00931.mxf':
    Metadata:
      operational_pattern_ul: 060e2b34.04010101.0d010201.01010900
      uid             : c3c82aa7-f530-11e7-8c91-985aebdab411
      generation_uid  : c3c82aa8-f530-11e7-98cb-985aebdab411
      company_name    : Adobe Systems Incorporated
      product_name    : Adobe Media Encoder
      product_version : 12.0.0
      application_platform: Mac OS X
      product_uid     : 0c3919fe-46e8-11e5-a151-feff819cdc9f
      modification_date: 2018-01-09T11:32:25.000000Z
      material_package_umid: 0x060A2B340101010501010D1113000000C8FC790227810580CC9A985AEBDAB411
      timecode        : 00:00:00:00
    Duration: 00:00:10.00, start: 0.000000, bitrate: 52434 kb/s
      Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, unknown/bt709/bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
      Metadata:
        file_package_umid: 0x060A2B340101010501010D1213DF61E1C8FC7902278105807C35985AEBDAB411
        file_package_name: Source Package
        track_name      : Track 1
      Stream #0:1: Audio: pcm_s24le, 48000 Hz, mono, s32 (24 bit), 1152 kb/s
      Metadata:
        file_package_umid: 0x060A2B340101010501010D1213DF61E1C8FC7902278105807C35985AEBDAB411
        file_package_name: Source Package
        track_name      : Track 2
      Stream #0:2: Audio: pcm_s24le, 48000 Hz, mono, s32 (24 bit), 1152 kb/s
      Metadata:
        file_package_umid: 0x060A2B340101010501010D1213DF61E1C8FC7902278105807C35985AEBDAB411
        file_package_name: Source Package
        track_name      : Track 3
  Stream mapping:
    Stream #0:0 -&gt; #0:0 (copy)
    Stream #0:1 -&gt; #0:1 (pcm_s24le (native) -&gt; pcm_s24le (native))
  Press [q] to stop, [?] for help
  Output #0, null, to 'pipe:':
    Metadata:
      operational_pattern_ul: 060e2b34.04010101.0d010201.01010900
      uid             : c3c82aa7-f530-11e7-8c91-985aebdab411
      generation_uid  : c3c82aa8-f530-11e7-98cb-985aebdab411
      company_name    : Adobe Systems Incorporated
      product_name    : Adobe Media Encoder
      product_version : 12.0.0
      application_platform: Mac OS X
      product_uid     : 0c3919fe-46e8-11e5-a151-feff819cdc9f
      modification_date: 2018-01-09T11:32:25.000000Z
      material_package_umid: 0x060A2B340101010501010D1113000000C8FC790227810580CC9A985AEBDAB411
      timecode        : 00:00:00:00
      encoder         : Lavf58.32.104
      Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, unknown/bt709/bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 25 tbc
      Metadata:
        file_package_umid: 0x060A2B340101010501010D1213DF61E1C8FC7902278105807C35985AEBDAB411
        file_package_name: Source Package
        track_name      : Track 1
      Stream #0:1: Audio: pcm_s24le, 192000 Hz, mono, s32 (24 bit), 4608 kb/s
      Metadata:
        file_package_umid: 0x060A2B340101010501010D1213DF61E1C8FC7902278105807C35985AEBDAB411
        file_package_name: Source Package
        track_name      : Track 2
        encoder         : Lavc58.56.101 pcm_s24le
  frame=  250 fps=0.0 q=-1.0 Lsize=N/A time=00:00:10.00 bitrate=N/A speed=  21x
  video:60771kB audio:5625kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
  [Parsed_loudnorm_0 @ 0000018c941ce700]
  {
          "input_i" : "-19.90",
          "input_tp" : "-1.69",
          "input_lra" : "2.40",
          "input_thresh" : "-30.39",
          "output_i" : "-23.28",
          "output_tp" : "-5.06",
          "output_lra" : "0.40",
          "output_thresh" : "-33.59",
          "normalization_type" : "dynamic",
          "target_offset" : "0.28"
  }
  </code></pre>
  
  <hr>
  
  <p>What can I put in the command to isolate this? </p>