{
  "date": "2026-07-13",
  "device": "Apple M2 Pro, 32GB RAM, macOS Version 26.5.1 (Build 25F80)",
  "corpus": "LibriSpeech test-clean (2620) + test-other (2939)",
  "results": [
    {
      "engine": "Apple SpeechAnalyzer",
      "split": "test-clean",
      "werPercent": 2.12,
      "realTimeFactor": 0.027,
      "utterances": 2620,
      "audioSeconds": 19452,
      "computeSeconds": 524
    },
    {
      "engine": "Apple SpeechAnalyzer",
      "split": "test-other",
      "werPercent": 4.56,
      "realTimeFactor": 0.032,
      "utterances": 2939,
      "audioSeconds": 19230,
      "computeSeconds": 606
    },
    {
      "engine": "Apple SFSpeechRecognizer (legacy)",
      "split": "test-clean",
      "werPercent": 9.02,
      "realTimeFactor": 0.03,
      "utterances": 2620,
      "audioSeconds": 19452,
      "computeSeconds": 587
    },
    {
      "engine": "Apple SFSpeechRecognizer (legacy)",
      "split": "test-other",
      "werPercent": 16.25,
      "realTimeFactor": 0.042,
      "utterances": 2939,
      "audioSeconds": 19230,
      "computeSeconds": 798
    },
    {
      "engine": "Whisper Tiny",
      "split": "test-clean",
      "werPercent": 7.88,
      "realTimeFactor": 0.023,
      "utterances": 2620,
      "audioSeconds": 19452,
      "computeSeconds": 440
    },
    {
      "engine": "Whisper Base",
      "split": "test-clean",
      "werPercent": 5.42,
      "realTimeFactor": 0.037,
      "utterances": 2620,
      "audioSeconds": 19452,
      "computeSeconds": 729
    },
    {
      "engine": "Whisper Small",
      "split": "test-clean",
      "werPercent": 3.74,
      "realTimeFactor": 0.08,
      "utterances": 2620,
      "audioSeconds": 19452,
      "computeSeconds": 1552
    },
    {
      "engine": "Whisper Tiny",
      "split": "test-other",
      "werPercent": 17.04,
      "realTimeFactor": 0.027,
      "utterances": 2939,
      "audioSeconds": 19230,
      "computeSeconds": 519
    },
    {
      "engine": "Whisper Base",
      "split": "test-other",
      "werPercent": 12.51,
      "realTimeFactor": 0.041,
      "utterances": 2939,
      "audioSeconds": 19230,
      "computeSeconds": 795
    },
    {
      "engine": "Whisper Small",
      "split": "test-other",
      "werPercent": 7.95,
      "realTimeFactor": 0.077,
      "utterances": 2939,
      "audioSeconds": 19230,
      "computeSeconds": 1477
    }
  ],
  "notes": "RTF measured with concurrent dev workload on the machine; re-measure idle before publishing speed claims. WER load-independent. 1/2939 legacy test-other utterances returned empty (scored as 100% WER misses)."
}