{
  "schema": "filemorf-audio-flagship-evidence/3",
  "generatedAt": "2026-09-03T02:44:41.931Z",
  "corpusVersion": "audio-v1",
  "rights": {
    "license": "CC0-1.0",
    "provenance": "Deterministic PCM signals generated from mathematical functions. No customer or third-party audio."
  },
  "source": {
    "repository": "https://github.com/jddelia/file-convert",
    "baseCommit": "e11eef48f52df732e0ef32d69f7ea10635b150bc",
    "workingTree": false,
    "generatorPath": "scripts/generate-audio-flagship-evidence.mjs",
    "publicGeneratorHref": "/fixtures/audio/v1/generate-audio-flagship-evidence.mjs.txt",
    "generatorSha256": "228ca719f843debbddd1e1b3482f2b6d406b3d89afab34ef7797eacf01c998c7",
    "rendererPath": "src/lib/audio/editor.ts",
    "rendererSha256": "159c26bb4f175dc8c823d2c70178f631d0125cf8059b3f8ea1494a3f3fba6479"
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  "environment": {
    "runner": "darwin arm64",
    "node": "v23.7.0",
    "referenceRuntime": "FFmpeg CLI",
    "engine": "ffmpeg version 8.1.2 Copyright (c) 2000-2026 the FFmpeg developers",
    "probeEngine": "ffprobe version 8.1.2 Copyright (c) 2007-2026 the FFmpeg developers",
    "browserRuntime": "@ffmpeg/ffmpeg 0.12.15 with @ffmpeg/core 0.12.10",
    "browserEvidenceStatus": "separate-release-gate"
  },
  "review": {
    "automatedContract": "passed-at-generation",
    "technical": "pending-independent-human-review",
    "nativeLanguage": "pending-human-review"
  },
  "publications": [
    {
      "id": "audio-v1-findings",
      "kind": "aggregate",
      "href": "/research/audio-v1-findings.csv",
      "mime": "text/csv",
      "bytes": 3029,
      "sha256": "ed33504ddd340d233eaadc356c849abff992ec5a43124cf18ab3a3eaff7b1eef"
    },
    {
      "id": "audio-v1-duration",
      "kind": "chart",
      "href": "/research/audio-v1-duration.svg",
      "mime": "image/svg+xml",
      "bytes": 3375,
      "sha256": "adbd06359d82a151ef8286906270db349b2b97fa88a2f65bc1bccaa20213545a"
    },
    {
      "id": "audio-v1-frequency",
      "kind": "chart",
      "href": "/research/audio-v1-frequency.svg",
      "mime": "image/svg+xml",
      "bytes": 3374,
      "sha256": "fd0a1945cbd4f9f2f8c75cb2ee3be154a277efe84b471f0914b1452e62be4289"
    },
    {
      "id": "audio-v1-signal-checks",
      "kind": "chart",
      "href": "/research/audio-v1-signal-checks.svg",
      "mime": "image/svg+xml",
      "bytes": 3035,
      "sha256": "c493a94d286191d26eb2a81de65fb9f904358927fe71ad7aafd0cc7019ec3050"
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  ],
  "records": {
    "audio-joiner": {
      "scope": "ffmpeg-cli-reference",
      "inputs": [
        {
          "href": "/fixtures/audio/v1/join-a-440hz.wav",
          "sha256": "146533ae274550b1aceb277c222323578d84c104122aa85e9b9421a3abef59f1",
          "bytes": 176444,
          "durationSec": 1,
          "sampleRate": 44100,
          "channels": 2,
          "mime": "audio/wav"
        },
        {
          "href": "/fixtures/audio/v1/join-b-660hz.wav",
          "sha256": "908fff30575445d37b4795f0c043d29424f50024954e83cb4daf65260db948b5",
          "bytes": 220544,
          "durationSec": 1.25,
          "sampleRate": 44100,
          "channels": 2,
          "mime": "audio/wav"
        }
      ],
      "output": {
        "href": "/fixtures/audio/v1/joined-reference.wav",
        "sha256": "514aa29dc0d71e255fc961e1f3ef2f81b3ad3f6190e96024ec3db915ef6e3959",
        "bytes": 396944,
        "durationSec": 2.25,
        "sampleRate": 44100,
        "channels": 2,
        "mime": "audio/wav"
      },
      "operation": "Two synthetic tones, ordered 440 Hz then 660 Hz, normalized to 44.1 kHz stereo, with 6 ms internal microfades.",
      "demonstrates": [
        "ordered concatenation",
        "6 ms boundary attenuation",
        "44.1 kHz stereo PCM output"
      ],
      "doesNotDemonstrate": [
        "browser performance",
        "cross-device equivalence"
      ],
      "assertions": [
        {
          "id": "output-duration",
          "comparator": "within",
          "expected": 2.25,
          "actual": 2.25,
          "tolerance": 0.02,
          "unit": "s"
        },
        {
          "id": "first-segment-frequency",
          "comparator": "within",
          "expected": 440,
          "actual": 440,
          "tolerance": 1,
          "unit": "Hz"
        },
        {
          "id": "second-segment-frequency",
          "comparator": "within",
          "expected": 660,
          "actual": 660,
          "tolerance": 1,
          "unit": "Hz"
        },
        {
          "id": "join-boundary-rms",
          "comparator": "lte",
          "expected": 0.01,
          "actual": 0.004157,
          "unit": "FS"
        }
      ],
      "command": [
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        "-hide_banner",
        "-loglevel",
        "error",
        "-i",
        "public/fixtures/audio/v1/join-a-440hz.wav",
        "-i",
        "public/fixtures/audio/v1/join-b-660hz.wav",
        "-filter_complex",
        "[0:a]atrim=start=0:end=1.000,asetpts=PTS-STARTPTS,aresample=44100,aformat=sample_fmts=fltp:channel_layouts=stereo,afade=t=out:st=0.9940:d=0.006[c0];[1:a]atrim=start=0:end=1.250,asetpts=PTS-STARTPTS,aresample=44100,aformat=sample_fmts=fltp:channel_layouts=stereo,afade=t=in:st=0:d=0.006[c1];[c0][c1]concat=n=2:v=0:a=1[out]",
        "-map",
        "[out]",
        "-vn",
        "-c:a",
        "pcm_s16le",
        "-map_metadata",
        "-1",
        "-bitexact",
        "public/fixtures/audio/v1/joined-reference.wav"
      ]
    },
    "audio-speed-changer": {
      "scope": "ffmpeg-cli-reference",
      "inputs": [
        {
          "href": "/fixtures/audio/v1/speed-metronome-523hz.wav",
          "sha256": "aebecf107510c32ee13e6c58e1b56edaaed84cc753c3af4dea8163f37eb0aa18",
          "bytes": 423404,
          "durationSec": 2.4,
          "sampleRate": 44100,
          "channels": 2,
          "mime": "audio/wav"
        }
      ],
      "output": {
        "href": "/fixtures/audio/v1/speed-075-keep-pitch-reference.wav",
        "sha256": "64a545d854b433d2e2ec33f837e431ceac8170dcb450154e60d7a5be7528b8ca",
        "bytes": 563364,
        "durationSec": 3.1934,
        "sampleRate": 44100,
        "channels": 2,
        "mime": "audio/wav"
      },
      "operation": "0.75× tempo with pitch-preserving FFmpeg atempo.",
      "demonstrates": [
        "0.75× duration change",
        "523.25 Hz reference-tone preservation"
      ],
      "doesNotDemonstrate": [
        "browser performance",
        "artifact-free output for arbitrary sources"
      ],
      "assertions": [
        {
          "id": "output-duration",
          "comparator": "within",
          "expected": 3.2,
          "actual": 3.1934,
          "tolerance": 0.04,
          "unit": "s"
        },
        {
          "id": "preserved-frequency",
          "comparator": "within",
          "expected": 523.25,
          "actual": 523.2,
          "tolerance": 1,
          "unit": "Hz"
        }
      ],
      "command": [
        "-y",
        "-hide_banner",
        "-loglevel",
        "error",
        "-i",
        "public/fixtures/audio/v1/speed-metronome-523hz.wav",
        "-filter:a",
        "atempo=0.7500",
        "-vn",
        "-c:a",
        "pcm_s16le",
        "-map_metadata",
        "-1",
        "-bitexact",
        "public/fixtures/audio/v1/speed-075-keep-pitch-reference.wav"
      ]
    },
    "slowed-and-reverb": {
      "scope": "ffmpeg-cli-reference",
      "inputs": [
        {
          "href": "/fixtures/audio/v1/slowed-impulse-330hz.wav",
          "sha256": "a600e57ae8d593bbc95b9e36335dd1ac89174abc1442df0ae3e1b5c345af6850",
          "bytes": 352844,
          "durationSec": 2,
          "sampleRate": 44100,
          "channels": 2,
          "mime": "audio/wav"
        }
      ],
      "output": {
        "href": "/fixtures/audio/v1/slowed-080-hall-reference.wav",
        "sha256": "dd94cf1832250f07cf8e3a526f543b48252c74a49928276e88ed3c72b5089fb5",
        "bytes": 540272,
        "durationSec": 3.0625,
        "sampleRate": 44100,
        "channels": 2,
        "mime": "audio/wav"
      },
      "operation": "FFmpeg hall aecho followed by the 0.8× tape-style resampling chain.",
      "demonstrates": [
        "0.8× tape-style pitch shift",
        "measurable echo tail after the dry slowed source"
      ],
      "doesNotDemonstrate": [
        "measured room convolution",
        "browser performance"
      ],
      "assertions": [
        {
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          "comparator": "within",
          "expected": 264,
          "actual": 264,
          "tolerance": 1,
          "unit": "Hz"
        },
        {
          "id": "echo-tail-rms",
          "comparator": "gte",
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          "actual": 0.031474,
          "unit": "FS"
        }
      ],
      "command": [
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        "-loglevel",
        "error",
        "-i",
        "public/fixtures/audio/v1/slowed-impulse-330hz.wav",
        "-filter:a",
        "aecho=0.8:0.9:300|450:0.4|0.25,aresample=44100,asetrate=35280,aresample=44100",
        "-vn",
        "-c:a",
        "pcm_s16le",
        "-map_metadata",
        "-1",
        "-bitexact",
        "public/fixtures/audio/v1/slowed-080-hall-reference.wav"
      ]
    },
    "voice-recorder": {
      "scope": "ffmpeg-cli-edit-reference",
      "inputs": [
        {
          "href": "/fixtures/audio/v1/synthetic-voice-like-source.wav",
          "sha256": "28835d200d0421781b2c233e4600315c16da812e32eab457a52c678f6a6b2046",
          "bytes": 388124,
          "durationSec": 2.2,
          "sampleRate": 44100,
          "channels": 2,
          "mime": "audio/wav"
        }
      ],
      "output": {
        "href": "/fixtures/audio/v1/voice-edit-trim-reference.wav",
        "sha256": "6035d39c967ca1fe457ae3ceb0b7f72f01b4ea0177c983192eb760e8a61364fa",
        "bytes": 317564,
        "durationSec": 1.8,
        "sampleRate": 44100,
        "channels": 2,
        "mime": "audio/wav"
      },
      "operation": "Synthetic voice-like signal with 0.2 s trimmed from each edge and PCM WAV output.",
      "demonstrates": [
        "deterministic timeline trim",
        "sample-aligned PCM WAV output"
      ],
      "doesNotDemonstrate": [
        "microphone permission",
        "MediaRecorder capture",
        "browser performance"
      ],
      "assertions": [
        {
          "id": "trimmed-duration",
          "comparator": "within",
          "expected": 1.8,
          "actual": 1.8,
          "tolerance": 0.02,
          "unit": "s"
        },
        {
          "id": "source-alignment-rms",
          "comparator": "lte",
          "expected": 0.000001,
          "actual": 0,
          "unit": "FS"
        }
      ],
      "command": [
        "-y",
        "-hide_banner",
        "-loglevel",
        "error",
        "-i",
        "public/fixtures/audio/v1/synthetic-voice-like-source.wav",
        "-filter:a",
        "atrim=start=0.200:end=2.000,asetpts=PTS-STARTPTS,aresample=44100,aformat=sample_fmts=fltp:channel_layouts=stereo",
        "-vn",
        "-c:a",
        "pcm_s16le",
        "-map_metadata",
        "-1",
        "-bitexact",
        "public/fixtures/audio/v1/voice-edit-trim-reference.wav"
      ]
    }
  }
}