{
  "date": "2026-10-13",
  "environment": "Actual CompressVid job builder via FreeConvert API; local decoding",
  "sources": [
    {
      "name": "synthetic-10s.mp4",
      "bytes": 10645710,
      "duration_seconds": 10,
      "video_stream_count": 1,
      "audio_stream_count": 1,
      "audio_codecs": [
        "aac"
      ],
      "sample_rates_hz": [
        48000
      ],
      "channels": [
        1
      ],
      "sha256": "e97cd7efa4cc5eadc8f53c03d66510d52ad2027e1f88565d73f0a7a288db1c98"
    },
    {
      "name": "synthetic-ringtone-45s.mp3",
      "bytes": 1081513,
      "duration_seconds": 45,
      "video_stream_count": 0,
      "audio_stream_count": 1,
      "audio_codecs": [
        "mp3"
      ],
      "sample_rates_hz": [
        44100
      ],
      "channels": [
        1
      ],
      "sha256": "85d41e8a09f3d7dc8b2d8b26b8f8ad0335bbd2bb321fc719505895ff2193bac9"
    }
  ],
  "runs": [
    {
      "name": "audio-wav-baseline",
      "source": "synthetic-10s.mp4",
      "requested": {
        "outputFormat": "wav",
        "startSec": 2,
        "endSec": 8,
        "volume": 100
      },
      "provider_output_format": "wav",
      "options": {
        "cut_start": "00:00:02.00",
        "cut_end": "00:00:08.00",
        "audio_codec": "pcm_s16le"
      },
      "output": {
        "bytes": 576078,
        "duration_seconds": 6,
        "video_stream_count": 0,
        "audio_stream_count": 1,
        "audio_codecs": [
          "pcm_s16le"
        ],
        "sample_rates_hz": [
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        ],
        "channels": [
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        ],
        "sha256": "2e7c702a8512470701e5f7b966276fc211be9d0e7509589c8334bcbdd7fd5115",
        "format_name": "wav"
      }
    },
    {
      "name": "audio-wav-half-volume",
      "source": "synthetic-10s.mp4",
      "requested": {
        "outputFormat": "wav",
        "startSec": 2,
        "endSec": 8,
        "volume": 50
      },
      "provider_output_format": "wav",
      "options": {
        "cut_start": "00:00:02.00",
        "cut_end": "00:00:08.00",
        "audio_filter_volume": 50,
        "audio_codec": "pcm_s16le"
      },
      "output": {
        "bytes": 576078,
        "duration_seconds": 6,
        "video_stream_count": 0,
        "audio_stream_count": 1,
        "audio_codecs": [
          "pcm_s16le"
        ],
        "sample_rates_hz": [
          48000
        ],
        "channels": [
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        ],
        "sha256": "14c6c219d364f821413d50e6ebe3466304bf9c5bcf7493f55c0f417707c73f54",
        "format_name": "wav"
      }
    },
    {
      "name": "audio-wav-half-volume-fades",
      "source": "synthetic-10s.mp4",
      "requested": {
        "outputFormat": "wav",
        "startSec": 2,
        "endSec": 8,
        "volume": 50,
        "fadeIn": true,
        "fadeOut": true
      },
      "provider_output_format": "wav",
      "options": {
        "cut_start": "00:00:02.00",
        "cut_end": "00:00:08.00",
        "audio_filter_volume": 50,
        "audio_filter_fade_in": true,
        "audio_filter_fade_out": true,
        "audio_codec": "pcm_s16le"
      },
      "output": {
        "bytes": 576078,
        "duration_seconds": 6,
        "video_stream_count": 0,
        "audio_stream_count": 1,
        "audio_codecs": [
          "pcm_s16le"
        ],
        "sample_rates_hz": [
          48000
        ],
        "channels": [
          1
        ],
        "sha256": "f84639afa44b89553dce1160f6e020137243e46fb5a918fb0860b58d4d659004",
        "format_name": "wav"
      }
    },
    {
      "name": "audio-mp3-trim",
      "source": "synthetic-10s.mp4",
      "requested": {
        "outputFormat": "mp3",
        "startSec": 2,
        "endSec": 8
      },
      "provider_output_format": "mp3",
      "options": {
        "cut_start": "00:00:02.00",
        "cut_end": "00:00:08.00",
        "audio_codec": "libmp3lame",
        "audio_rate_control_mp3": "cbr",
        "audio_bitrate_mp3": "160k"
      },
      "output": {
        "bytes": 121107,
        "duration_seconds": 6,
        "video_stream_count": 0,
        "audio_stream_count": 1,
        "audio_codecs": [
          "mp3"
        ],
        "sample_rates_hz": [
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        ],
        "channels": [
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        ],
        "sha256": "6eb0c6b3a860ba5c371eb684ba4a151a1926d6fb9242a02d9ee270f53973b6ce",
        "format_name": "mp3"
      }
    },
    {
      "name": "ringtone-30s",
      "source": "synthetic-ringtone-45s.mp3",
      "requested": {
        "outputFormat": "m4r",
        "startSec": 5,
        "endSec": 35,
        "fadeIn": true,
        "fadeOut": true
      },
      "provider_output_format": "m4a",
      "options": {
        "cut_start": "00:00:05.00",
        "cut_end": "00:00:35.00",
        "audio_filter_fade_in": true,
        "audio_filter_fade_out": true,
        "audio_codec": "aac",
        "audio_bitrate_aac": "128k"
      },
      "output": {
        "bytes": 434744,
        "duration_seconds": 30,
        "video_stream_count": 0,
        "audio_stream_count": 1,
        "audio_codecs": [
          "aac"
        ],
        "sample_rates_hz": [
          44100
        ],
        "channels": [
          1
        ],
        "sha256": "61fe485464cd05b34a8a1c0510da1b44498d562068bafd0d0c6057257ee60d16",
        "format_name": "mov,mp4,m4a,3gp,3g2,mj2"
      }
    }
  ],
  "source_generation": {
    "video_record": "/blog/evidence/edit-tools-20261013.json",
    "ringtone_command": "ffmpeg -f lavfi -i sine=frequency=440:sample_rate=44100:duration=45 -c:a libmp3lame -b:a 192k synthetic-ringtone-45s.mp3",
    "ffmpeg_version": "ffmpeg version 8.1.2 Copyright (c) 2000-2026 the FFmpeg developers"
  },
  "limitation": "Synthetic tones only. No listening-quality ranking, speech denoising test, iPhone install or billing verification.",
  "signal_inspection": {
    "method": "Decode each file to mono float PCM at 48000 Hz; RMS windows in seconds.",
    "middle_window": [
      2.875,
      3.125
    ],
    "baseline_rms": 0.08838062015824592,
    "half_volume_rms": 0.04419034451521735,
    "amplitude_ratio": 0.5000003896339981,
    "gain_db": -6.020593144646448,
    "faded_first_250ms_rms": 0.0021248300891445688,
    "faded_middle_rms": 0.043272638511611894,
    "faded_last_250ms_rms": 0.00212409260516617,
    "limitation": "RMS is signal amplitude, not perceived loudness or an audio-quality score. Hosted fade duration is not an adjustable UI control."
  },
  "local_video_audio_edit": {
    "filter": "volume=0.5,afade=t=in:st=0:d=1,afade=t=out:st=9:d=1",
    "source_video_payload_sha256": "37b0f47e0a51400c8e2e4d570325fedb2477118e7b81b84f1243525939bc0bb3",
    "output_video_payload_sha256": "37b0f47e0a51400c8e2e4d570325fedb2477118e7b81b84f1243525939bc0bb3",
    "video_payload_match": true,
    "file_sha256": "e9620cde31968139f222b8211a31baad62ec129d08b5a50d343f3d13647aba4e",
    "limitation": "One H.264/AAC source; copied video packets, AAC audio re-encoded. Does not validate all containers, synchronization cases or metadata."
  },
  "local_additional_recipes": [
    {
      "name": "local-audio-edited-clip.mp4",
      "duration_seconds": 6.0,
      "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
      "audio_codecs": [
        "aac"
      ],
      "video_stream_count": 1
    },
    {
      "name": "local-ringtone.m4r",
      "duration_seconds": 30.0,
      "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
      "audio_codecs": [
        "aac"
      ],
      "video_stream_count": 0
    }
  ]
}