{
  "_": "Golden vector for the JRay v1 audio signature (JRay-public-server SPEC.md \u00a73). Shared verbatim between scene-actor-extraction (C++) and the jRay Jellyfin plugin (C#) so the two implementations can be proven bit-identical. IR-004, IR-005, IR-007, IR-008.",
  "version": "v1",
  "signature": "v1: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",
  "frame_count": 1288,
  "media": {
    "file": "jray_audio_v1_tone.flac",
    "generator": "make_fixture.py",
    "container": "FLAC (lossless \u2014 decodes to exactly the PCM make_fixture.py emits)",
    "duration_sec": 120.0,
    "sample_rate": 11025,
    "channels": 1,
    "sample_format": "s16",
    "sha256": "912ecd426cd426dccb37753e0249694227619c701cb9f533502b37da0fbe8096",
    "bytes": 585142
  },
  "decoded_window": {
    "_": "Checksums of the 120 s centre window after downmix to mono and resample to 11025 Hz, i.e. exactly the stream `ffmpeg -ss <mid-60> -t 120 -i <file> -vn -ac 1 -ar 11025 -f f32le -` produces. Check these first: a mismatch here is a decode problem, not a DSP one.",
    "samples": 1323000,
    "f32le_fnv1a64": "0x1ef7899cd4d12662",
    "s16le_fnv1a64": "0xf824fa56f125c0dc"
  },
  "params": {
    "window_sec": 120.0,
    "window_centre": "runtime/2, i.e. samples from runtime/2 - 60 s; truncated to exactly 1323000 samples",
    "min_duration_sec": 120.0,
    "min_duration_rule": "IR-007 \u2014 below this emit NO signature and apply no sync offset",
    "sample_rate": 11025,
    "channels": 1,
    "arithmetic": "IEEE-754 double throughout; float32 is not sufficient",
    "sample_scale": "s16 * (1/32768), FFmpeg's native s16->flt",
    "frame_size": 4096,
    "hop_size": 1024,
    "frame_count_rule": "1 + (n_samples - 4096) / 1024, integer division; whole frames only",
    "window_fn": "Hann, PERIODIC: w[n] = 0.5 * (1 - cos(2*pi*n/4096))",
    "transform": "radix-2 DIT complex FFT over the 4096 real samples (imag=0), no normalisation",
    "magnitude": "sqrt(re^2 + im^2), linear",
    "band_lo_hz": 300.0,
    "band_hi_hz": 3000.0,
    "num_bands": 32,
    "band_edges": "edge[b] = 300 * (3000/300)^(b/32), b = 0..32",
    "band_bins": "band b owns FFT bins [k_lo[b], k_lo[b+1]) with k_lo[b] = ceil(edge[b] * 4096 / 11025); see band_fft_bins",
    "band_value": "MEAN of the linear magnitudes in the band (not sum, not max)",
    "peak_bin": "argmax over the 32 band values; ties resolve to the LOWEST index",
    "energy_metric": "E = mean magnitude over all FFT bins 112..1114, i.e. the whole 300-3000 Hz band",
    "energy_reference": "upper median of E over all frames: sorted[n/2], no averaging of the two middle values",
    "energy_ratio": "r = log10((E + 1e-12) / (E_ref + 1e-12))",
    "energy_class_edges": [
      -0.6,
      -0.2,
      0.2
    ],
    "energy_class": "0 if r < -0.6, 1 if r < -0.2, 2 if r < 0.2, else 3",
    "byte_layout": "bit7 = 0 (reserved), bits6..2 = 5-bit band index, bits1..0 = 2-bit energy class; byte = (band << 2) | class",
    "base64": "standard alphabet A-Za-z0-9+/ with '=' padding",
    "prefix": "v1:"
  },
  "band_fft_bins": [
    [
      112,
      120
    ],
    [
      120,
      129
    ],
    [
      129,
      139
    ],
    [
      139,
      149
    ],
    [
      149,
      160
    ],
    [
      160,
      172
    ],
    [
      172,
      185
    ],
    [
      185,
      199
    ],
    [
      199,
      213
    ],
    [
      213,
      229
    ],
    [
      229,
      246
    ],
    [
      246,
      265
    ],
    [
      265,
      285
    ],
    [
      285,
      306
    ],
    [
      306,
      328
    ],
    [
      328,
      353
    ],
    [
      353,
      379
    ],
    [
      379,
      408
    ],
    [
      408,
      438
    ],
    [
      438,
      471
    ],
    [
      471,
      506
    ],
    [
      506,
      543
    ],
    [
      543,
      584
    ],
    [
      584,
      627
    ],
    [
      627,
      674
    ],
    [
      674,
      724
    ],
    [
      724,
      778
    ],
    [
      778,
      836
    ],
    [
      836,
      899
    ],
    [
      899,
      966
    ],
    [
      966,
      1038
    ],
    [
      1038,
      1115
    ]
  ],
  "notes": [
    "The server spec fixes the window, rate, STFT geometry, band and the 5+2 bit packing. Everything under params beyond that (Hann periodicity, band aggregation, the energy-class definition, tie-breaking, base64 alphabet) is pinned HERE for v1 \u2014 the spec does not constrain it, and two implementations that guess differently produce non-matching signatures.",
    "Decision margins on this fixture: the two strongest bands are within 1.3% on the closest frame, and the closest frame to an energy-class edge is 3.6e-3 away in log10. Both are many orders of magnitude above double-precision FFT differences, so any two correct double- precision implementations agree; a float32 implementation is not guaranteed to.",
    "Coverage: all 32 bands and all 4 energy classes appear in the golden signature.",
    "Robustness observed on this fixture: identical peak-bin sequence after a stereo/44100 Hz round trip and after AAC 128 kbit/s re-encoding."
  ]
}