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Preservation architecture

Change the container.
Respect the footage.

Uncrush separates analysis, planning, writing, and verification so a narrow container change cannot quietly become a media change.

01

Safe path

Publication is the last step,
not the optimistic one.

The native faststart-v1 path implements this architecture. Browser processing and other transformation profiles remain planned.

  1. 01

    Analyze immutable source

    Read one stable source snapshot under explicit limits.

  2. 02

    Build a bounded plan

    Explain every approved range copy and container rewrite.

  3. 03

    Transform

    Stream supported bytes without unnecessary decoding or re-encoding.

  4. 04

    Reopen output

    Treat the generated candidate as a new, independent input.

  5. 05

    Analyze independently

    Apply the same parser and supported-profile checks again.

  6. 06

    Verify invariants

    Compare required encoded media and exact declared meaning.

  7. 07

    Publish after verification

    Release the candidate only when every required gate succeeds.

02

Boundaries

One mission.
Three evidence levels.

Current code · v0.1

Implemented

The native codebase analyzes supported MOV/MP4, verifies encoded media and container semantics, and creates verified same-container fast-start copies.

  • Bounded MOV/MP4 analysisReads the supported container profile with explicit limits and exact integer timing.
  • Canonical encoded-sample identityDescribes selected encoded video and audio samples in a stable, versioned form.
  • Direct safe-transform-v1 verificationCompares encoded payloads, timing, decoder setup, geometry, color, and audio meaning between supported files.
  • Native CLI foundationProvides analysis, identity, verification, and verified same-container fast-start commands.
  • Source-bound transformation planningBinds checked copy and rewrite actions to one exact immutable source snapshot.
  • Bounded streaming container writerCopies supported media through a reusable buffer without decoding or re-encoding it.
  • Verified faststart-v1Moves moov for same-container fast-start output and rewrites required absolute chunk offsets.
  • Generated-output re-analysisReopens the private candidate and analyzes it independently before publication.
  • Mandatory publication gatePublishes media only after container-copy checks pass and safe-transform-v1 returns verified.

Current boundary

In development

No browser processor or next media transformation is active. Uncrush will define the next phase in a separate design.

    Later milestones

    Planned

    MOV-to-MP4 remux, browser/WASM processing, platform profiles, and controlled platform research require separate milestones and evidence.

    • MOV-to-MP4 remuxPlanned for an approved source profile; faststart-v1 keeps MOV as MOV and MP4 as MP4.
    • Browser WASM processorIntended to run approved processing locally in a future browser experience.
    • Versioned platform profilesPlanned profiles will encode measured, reviewable preparation rules instead of folklore.
    • Controlled rendition experimentsLater research will compare retrieved delivery renditions under documented conditions.
    • Mobile applicationsiOS and Android experiences remain future work after the portable processing boundary exists.
    03

    What “preserve” means

    Bytes and meaning
    travel together.

    Keeping encoded video and audio samples is necessary. It is not enough. Their order, decode and presentation timing, edit mapping, decoder configuration, geometry, color, and audio metadata also matter.

    Unknown layout-coupled state fails closed. If Uncrush cannot prove that a transformation is safe under a named policy, the output must not be published as verified.