Files
hyperframes/packages
James RussoandClaude Opus 4.7 21f5066832 feat(producer): enable webm in distributed mode via concat-copy (#951)
* feat(producer): enable webm in distributed mode via concat-copy

PR 8.2 of the WebM distributed-rendering plan (v1.5 backlog #1; see
DISTRIBUTED-RENDERING-PLAN.md §7.2). Wires libvpx-vp9 webm through the
distributed pipeline now that PR 8.1 proved concat-copy works.

Architectural decision: Path A (concat-copy) — based on PR 8.1's smoke
test result (9/9 tests pass for both yuv420p and yuva420p VP9 streams).
The simpler architecture wins; no re-encode in assemble, no encode-
parallelism loss.

Changes:

- plan.ts:
  - DistributedRenderConfig.format and PlanResult.format now include
    "webm" — type-level acceptance matches the runtime gate.
  - rejectUnsupportedDistributedFormat() no longer trips on webm. HDR
    mp4 remains the only refused configuration.
  - resolveEncoderTriple() returns libvpx-vp9-software + yuva420p +
    preset="good" for format="webm". yuva420p preserves alpha — the
    format's main reason for existing for web delivery.
  - codec= remains rejected for non-mp4 formats (mov is always ProRes
    4444; webm is always libvpx-vp9). The error message lists all four
    distributed-supported formats.
  - FormatNotSupportedInDistributedError docstring updated to reflect
    the new reality (only HDR is unsupported).

- freezePlan.ts: LockedRenderConfig.encoder gains "libvpx-vp9-software".
  Mirrors libx265-software / prores-software / png-sequence in shape;
  the chunk worker reads this discriminant to decide encode args.

- renderChunk.ts: drops the now-incorrect cast that excluded webm from
  buildSyntheticRenderJob's format input; tightens the preset-format
  cast to include webm.

- assemble.ts: docstring + comment updates. The mp4/mov concat-copy
  path is format-agnostic — webm uses the exact same code (applyFaststart
  is a no-op for webm via the existing chunkEncoder.ts gate;
  muxVideoWithAudio already routes webm to libopus audio).

- planFormatBanlist.test.ts: webm-rejection tests removed; replaced with
  "accepts webm" tests + a HDR+webm combo test that verifies HDR is the
  trip regardless of format.

- plan.test.ts: new describe block pins the webm wiring contract:
  format="webm" produces an encoder=libvpx-vp9-software /
  pixelFormat=yuva420p planDir with closedGop=true and gopSize=chunkSize.

- webm-concat-copy.test.ts (smoke): extended with a yuva420p variant
  that proves the alpha pixel format the distributed pipeline actually
  emits also round-trips through concat-copy. 9/9 tests pass locally.

§8 format support matrix in DISTRIBUTED-RENDERING-PLAN.md is intentionally
left unchanged at this PR — it flips to ✓ in PR 8.4 once the end-to-end
fixture (PR 8.3) is green.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(producer): include webm in plan-time needsAlpha + strengthen alpha smoke

PR review feedback from Miguel and Vai on #951 caught a real bug:
`plan.ts`'s `needsAlpha` disjunction excluded `"webm"`, so the plan
stage froze `forceScreenshot: false` into the `LockedRenderConfig`
even though distributed webm uses `yuva420p`. Every chunk worker
captured opaque RGB via BeginFrame (which doesn't preserve alpha on
Linux headless-shell), and libvpx-vp9 encoded uniformly-opaque alpha
that the encoder then dropped — producing un-keyable webm.

Two changes:

1. **plan.ts**: include `"webm"` in `needsAlpha`. Matches the
   in-process renderer's logic at `renderOrchestrator.ts:1469`
   (`const needsAlpha = isWebm || isMov || isPngSequence`); the two
   sites must stay in sync since the distributed pipeline's PSNR
   regression compares against the in-process baseline.

2. **Smoke test (yuva420p describe)**: source frames now use a real
   alpha gradient (`geq=a='X*255/W'` on top of `testsrc2`) instead of
   `testsrc2 + format=rgba` which was uniformly opaque. The decode-
   pix_fmt assertion is dropped (ffprobe reports `yuv420p` for
   VP9-with-alpha because the alpha lives in a Matroska
   `BlockAdditional` sidecar) and replaced with two stronger checks:
   - `TAG:ALPHA_MODE=1` is present on the stream — proves the
     encoder was actually configured for alpha
   - alpha plane variance after `-c:v libvpx-vp9 -i ... -pix_fmt rgba
     -vf extractplanes=a,signalstats` — proves the alpha sub-stream
     round-trips through concat-copy with spatially-varying content,
     not uniform/dropped alpha
   - decode-test gate is now exit-code-only (was `exitCode || stderr`
     which would flake on chatty ffmpeg `-v error` builds emitting
     non-fatal DTS/container notes)

These checks would have caught the `needsAlpha` bug before review.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(aws-lambda): widen narrow format types to include webm

CI on PR #951 was failing at typecheck/build because the producer's
`DistributedRenderConfig.format` widened to include webm in this PR
but the aws-lambda package's narrow `"mp4" | "mov" | "png-sequence"`
type literals in `events.ts`, `handler.ts`, and `validateConfig.ts`
hadn't kept up. `renderToLambda.ts:87` passed `config.format` (now
including webm) into a parameter typed against the narrow union,
producing TS2345.

This widening originally landed in PR #952 (test fixture PR) but
needs to be atomic with the producer's widening here to keep each
PR independently typecheck-clean.

Also refactor `formatExtension` from a switch dispatch to a
`Record<DistributedFormat, string>` lookup. Adding the webm case
tipped the switch's CRAP to the 30.0 fallow threshold; the lookup
table drops cyclomatic from 5 to 1 with the same compile-time
exhaustiveness guarantee (TS errors on missing entries when
`DistributedFormat` adds a new format). The runtime
`_exhaustive: never` throw was only protecting against a string
slipping past TS; `validateConfig.ts`'s `ALLOWED_FORMATS` already
gates untrusted input at the SDK boundary.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-19 02:46:21 -04:00
..
2026-05-19 02:33:31 +00:00