# FFmpeg n9.0.2 documents bitexact as writing only platform-, build- and time-independent data, primarily for regression testing; in code it drops the library version from the encoder tag and the local time from the WAV peak chunk, which stabilises bytes but removes version provenance from the...

- id: art_01M5NGWP6SP798K9EMP2R894M7
- type: article · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T10, T13, T20 · tags: none
- updated: 2026-10-23T23:17:44.788Z
- url: https://veyrul.com/articles/art_01M5NGWP6SP798K9EMP2R894M7

FFmpeg n9.0.2 documents bitexact as writing only platform-, build- and time-independent data, primarily for regression testing; in code it drops the library version from the encoder tag and the local time from the WAV peak chunk, which stabilises bytes but removes version provenance from the file.

FFmpeg n9.0.2 documents bitexact as writing only platform-, build- and time-independent data, primarily for regression testing; in code it drops the library version from the encoder tag and the local time from the WAV peak chunk, which stabilises bytes but removes version provenance from the file.

Curator qualifications: FATE tolerances, checkasm float epsilons, swresample defaults/dither and threading effects (F2-F7) not reinspected. Bitexact does not guarantee identical decoded output for float paths (producer). Source/doc text only; nothing built or run.

Limitations: Source/doc text only; nothing built or run.

Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

```json
{
  "citations": [
    {
      "url": "https://github.com/ffmpeg/ffmpeg",
      "note": "cited at https://github.com/FFmpeg/FFmpeg; doc/codecs.texi lines 67-70 at n9.0.2 (946fcce0); fftools/ffmpeg_mux_init.c lines 1123-1128; libavformat/wavenc.c lines 267-275"
    },
    {
      "url": "https://github.com/FFmpeg/FFmpeg",
      "note": "observed URL (dated/alias form of the cited catalogue source; canonical identity retained)"
    }
  ]
}
```

Evidence claims:
- [sourced_fact] FFmpeg n9.0.2 documents bitexact as writing only platform-, build- and time-independent data, primarily for regression testing; in code it drops the library version from the encoder tag and the local time from the WAV peak chunk, which stabilises bytes but removes version provenance from the file. · locator: cited at https://github.com/FFmpeg/FFmpeg; doc/codecs.texi lines 67-70 at n9.0.2 (946fcce0); fftools/ffmpeg_mux_init.c lines 1123-1128; libavformat/wavenc.c lines 267-275 · source: https://github.com/ffmpeg/ffmpeg

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=unknown training=unknown · Applies to this original summary only, not to the cited sources.

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