[eugene-mux]

Description

Generated media is reinspected and accepted only with complete timeline proof, policy compliance, and a match to the conversion plan. Source and output MP4 inspection share one bounded sample/timeline scan and result type. Non-ISO scans return metadata only and select original bytes. Conversion requires proven source timing; the unused raw scanner and duration guesses have been removed.

Bitrate counts whole-track bytes over the full track span and complete intersecting GOPs over their full spans. Cadence and keyframe intervals use the presented edit. Timestamp comparison allows output-tick rounding and requires a consistent extractor timing convention across each track.

Timing tables are selected by platform track ID; metadata is no longer read twice.

Validation

• 166 unit tests pass in each debug/release variant; SDK/sample release builds, lint-vital, and whitespace checks pass.
• 36 API 36 emulator fixture cases pass, including leading/trailing GOP edits and Matroska planner fallback. Modern and forced-legacy reads agree.
• Duration, A/V-start, and aspect tolerances retain the Swift v1.2.0 baselines.

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Note

High Risk
Changes upload eligibility by requiring proven timelines and stricter bitrate/edit math; incorrect timeline or validation logic could reject good encodes or accept non-compliant output.

Overview
Adds post-conversion validation so generated files are only accepted after metadata + a complete ISO timeline scan, policy compliance, and a match to the conversion plan; rejections allow original-byte fallback, while cancellation stops preparation.

Replaces the old MediaSampleInspector file scan with StandardInputTimelineInspector: ISO stts/ctts/elst tables (via IsoTimelineReader) prove effective duration, A/V offset, and presentation times, then BoundedSampleReader verifies every sample against platform timestamps and derives video sample facts. VideoSampleFactsReader now keys cadence/timestamps off the presented edit window while bitrate/GOP bounds count whole-track bytes (including preroll/tails outside the edit).

StandardInputOutputValidator orchestrates reinspection (immutable file check, timeline completeness) and compares output to source timelines and StandardInputConversion (codec, dimensions, audio, cadence, timestamp preservation with tick rounding). PlanningCapabilities.sourceTimelineIsProven is required before conversion is offered.

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