{
  "name": "Synthetic music-ducking comparison",
  "created": "2026-09-08",
  "verifiedAt": "2026-09-08T02:19:09.654968+00:00",
  "backendSourceCommit": "b6f8ed84ed2057c979bcc47207ac5a1d74fb8c81",
  "creationSurface": "Local production-revision filtergraph builder and FFmpeg 7.1. No Studio agent request, account export or music-generation feature.",
  "sourceProvenance": "First 12 seconds of the already-published Valmera-authored motion-graphic source, with its silent soundtrack replaced by locally synthesized test tones. No customer footage, human voice or third-party song.",
  "originalSource": {
    "url": "https://valmera.io/examples/trim-and-reframe/original-source.mp4",
    "sha256": "24dc72de92df8e0d212fa9ca068d3ffdacab55f74b91c32249be96e9e74defdf"
  },
  "signals": {
    "musicBed": "220, 330 and 440 Hz sine waves, each amplitude 0.06; 48 kHz mono PCM16",
    "programAudio": "880 Hz sine wave, amplitude 0.3, active 2\u20134 and 6\u20138 seconds with 10 ms edge ramps; encoded into the source MP4"
  },
  "sharedSettings": {
    "durationSeconds": 12,
    "musicGainDb": 0,
    "fadeInSeconds": 0.2,
    "fadeOutSeconds": 0.5,
    "loop": false,
    "mastering": false
  },
  "difference": "Music duck=false versus duck=true with duck_mode=smooth; otherwise normalized EDLs match.",
  "rendererCompressor": {
    "threshold": 0.03,
    "ratio": 12,
    "attackMs": 180,
    "releaseMs": 550
  },
  "verification": {
    "variants": {
      "without-ducking": {
        "decodedSamplesMono48k": 576512,
        "decodedDurationSeconds": 12.010666666666667,
        "samplePeakDbfs": -7.710594534873962
      },
      "with-ducking": {
        "decodedSamplesMono48k": 576512,
        "decodedDurationSeconds": 12.010666666666667,
        "samplePeakDbfs": -8.775374293327332
      }
    },
    "backgroundMeasurement": "Relative FFT band magnitude (180\u2013500 Hz, Hann window) in corresponding decoded mono 48 kHz output intervals. Values compare ducking on against off; this is not a LUFS or subjective-quality score.",
    "windows": [
      {
        "label": "before",
        "start": 0.8,
        "end": 1.6,
        "backgroundBandChangeDb": 0.0
      },
      {
        "label": "first tone",
        "start": 3,
        "end": 3.8,
        "backgroundBandChangeDb": -14.004241035063279
      },
      {
        "label": "recovery",
        "start": 5,
        "end": 5.8,
        "backgroundBandChangeDb": 0.0044829225836861015
      },
      {
        "label": "second tone",
        "start": 7,
        "end": 7.8,
        "backgroundBandChangeDb": -13.992575541775805
      },
      {
        "label": "after",
        "start": 10,
        "end": 10.8,
        "backgroundBandChangeDb": 3.143868949211703e-05
      }
    ]
  },
  "files": {
    "music-bed.wav": {
      "bytes": 1152044,
      "sha256": "46a39eca5a2f31aafc6a466e9e9f2027f73773206eb87b9a75e3f36385991014"
    },
    "source-with-tones.mp4": {
      "bytes": 264410,
      "sha256": "541b76de444597184ca84fddd4e51de968f791e2d73ce2e6f0c00f92a58a8784"
    },
    "with-ducking.edl.json": {
      "bytes": 693,
      "sha256": "9fe33caf235e7285eb0d1d993a8a8a3203e0f23dea64b2b24933ec47bb3d4628"
    },
    "with-ducking.filtergraph.txt": {
      "bytes": 526,
      "sha256": "81505c6a584328fffdbe64a6e1dc85ce15a6f7a2f64339b04482c9c605b05fac"
    },
    "with-ducking.m4a": {
      "bytes": 285258,
      "sha256": "8b0bc0ab6d8c9f859b3c38ed16f7c8779ee1b21f72518bfda16226f8aba8a180"
    },
    "without-ducking.edl.json": {
      "bytes": 690,
      "sha256": "101761a23360aefe23d3615b68da92aed3af08e957d0554565399c9ad8d84f98"
    },
    "without-ducking.filtergraph.txt": {
      "bytes": 408,
      "sha256": "102c46ce8ef1b034d0172f75b9f96c5a329ca7017357851228e47368a96bbf96"
    },
    "without-ducking.m4a": {
      "bytes": 291513,
      "sha256": "8ea566b099b2702f3ba4dbdb8ded048e48315c0edc315cd0c76428b6742c8910"
    },
    "README.md": {
      "bytes": 2253,
      "sha256": "66a98ff26da232d081143552e5b1d285874900d0fc894a77c210e376f402664b"
    }
  },
  "limitations": [
    "Synthetic tones demonstrate level-triggered ducking, not speech recognition, voice intelligibility or song-selection quality.",
    "No voiceover ducking, looping, source separation, mastering, account branding or prompt success tested.",
    "Same gain and codec settings, but the files are intentionally not loudness matched: gain reduction is the demonstrated effect.",
    "Sample peak is measured after decode, not a true-peak compliance measurement."
  ]
}