Merge streaming-overhaul into dev (Opus low-data streaming, windowed streaming, HW-accel-off stabilization)
This commit is contained in:
daniel-c-harvey
@@ -1,27 +1,54 @@
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# Phase 21 — Windowed Streaming Buffer (bounded client memory for long streams)
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Product spec. Status: **design / framing — implementation-ready pending Daniel's open-question calls.**
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Author: product-designer. Date: 2026-06-23. **No code has been written by this doc.**
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Product spec. Status: **LANDED 2026-06-24 on `streaming-overhaul`.** See `COMPLETED.md` for the full
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as-built record. Author: product-designer. Date: 2026-06-23 (reconciliation pass after Phase 18 landed).
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> **AS-BUILT NOTE — Direction A→B pivot (2026-06-24).** This spec recommended **Direction A** (sliding
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> window on one open-ended forward stream, pausing `ReadAsync`/the segment loop to backpressure the
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> socket) and held **Direction B** (discrete bounded `Range: bytes=start-end` segments, §3.2) as the
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> documented fallback. **21.4 browser validation proved Direction A insufficient for Blazor WASM:** the
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> browser `fetch` API buffers the entire HTTP response body regardless of read pace — pausing reads
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> bounded the *decode* but not the *network download*, so the whole ~970 MB body accumulated in browser
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> memory even with the application decoding only a window of it. **We shipped Direction B.** The forward
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> stream now issues sequential 4 MB bounded Range requests (`SegmentSizeBytes = 4 MB`), fetched via
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> `RunSegmentedStreamAsync` in `StreamingAudioPlayerService`, each issued only after
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> `PlaybackScheduler.evaluateProductionPause()` clears below low-water. Browser holds ~one 4 MB segment
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> of raw bytes; 21.4 confirmed network-memory bounding in Daniel's browser run. The decode-side windowing
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> (21.1/21.2) is unchanged and pairs with Direction B; seek/refill converge on the same segmented loop
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> via `RecoverFromFailedRefill`. Direction A is recorded as tried-in-validation and found insufficient
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> for the WASM `fetch` runtime. Sections §3.2–§3.3 below retain the original A vs. B vs. C analysis as
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> the decision record; **Direction B is what shipped.**
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Surface: **public listener site only** (`DeepDrftPublic.Client` player stack + `DeepDrftPublic`
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TypeScript audio interop). No CMS (`DeepDrftManager`) change. No data-model or schema change. The one
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server touch is **reuse, not new surface**: the existing `DeepDrftAPI` HTTP `Range: bytes=X-`
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partial-content primitive (Phase 4, landed) is the load-bearing dependency; this phase adds no new API
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endpoint.
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> **Sequencing dependency (Daniel, 2026-06-23): Phase 18 (Opus Low-Data Streaming) comes BEFORE this
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> phase.** Format support — specifically the derived **Ogg Opus fullband 320** low-data delivery path
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> (`product-notes/phase-18-opus-low-data-streaming.md`) — is a prerequisite that sequences ahead of
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> windowing. Phase 21's windowing must work across **both** delivery formats (lossless WAV and Opus).
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> Its C5 invariant below already anticipated this ("must not foreclose MP3/FLAC"); **Opus is now the
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> concrete VBR/containerized driver of C5.** Windowing an Opus stream uses the decoder's **accurate
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> index-based** byte↔time mapping (`OpusFormatDecoder.calculateByteOffset` — a binary search in the Phase 18
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> precomputed seek index), exactly the C5 case — *not* the exact CBR-WAV `byteRate` math, and *not*
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> approximate Ogg-page interpolation. **Correction (Daniel, 2026-06-23):** an earlier draft described the
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> Opus mapping as "approximate page interpolation"; the Phase 18 seek-model resolution rejected that — Opus
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> seeking is **accurate**, backed by a precomputed seek index built at transcode time, so refill resolves to
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> the *exact* page offset. The windowed refill controller calls the **same** index resolver an explicit seek
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> does (Phase 18 §3.4a D); a window opening away from byte 0 still decodes via the Phase 18 sidecar setup
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> header. Build the window machinery format-agnostically (§2 C3/C5) so it inherits Opus for free.
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> **Phase 18 (Opus Low-Data Streaming) has LANDED (2026-06-23, `COMPLETED.md`). This spec is reconciled
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> to the as-built reality.** Phase 18 changed the landscape in two ways that reshape this phase:
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>
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> 1. **There are now TWO decode paths feeding the one `PlaybackScheduler`, not one.** (a) The original
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> **WAV/MP3/FLAC** path — `StreamDecoder` → `IFormatDecoder` (wrap-each-segment + `decodeAudioData`).
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> (b) A new **Opus** path — `OggDemuxer` → `OpusStreamDecoder` (the `IStreamingDecoder` seam, a stateful
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> **WebCodecs `AudioDecoder`** pipeline). The §3.1 unbounded-memory root cause (the scheduler's
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> push-only `AudioBuffer[]`) applies to **both** — but the Opus path adds a *second* accumulation locus
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> upstream of the scheduler (the WebCodecs decode queue + `decodedQueue: AudioData[]`), so windowing it
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> is not the same mechanism as windowing WAV. See §3.1.
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> 2. **The accurate index-driven Opus seek the original spec assumed Phase 21 would build is ALREADY
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> LIVE.** Phase 18 ships `resolveOpusByteOffset` (binary-search the precomputed seek index in
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> `OpusSeekData`) → Range fetch → `OpusStreamDecoder.reinitializeForRangeContinuation(landingTime,
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> target)` with frame-accurate lead-trim. Opus seek is **accurate, not approximate** — and **already
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> shipping**. Phase 21 does **not** build Opus seek; it **reuses** that live seek for window-miss
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> refills.
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>
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> **Correction of stale spec language.** The original draft described Opus as a future-wired
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> `OpusFormatDecoder.calculateByteOffset` joining the `IFormatDecoder` registry, with seek as "approximate
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> vs accurate." All of that is now wrong against the landed code: Opus does **not** use `IFormatDecoder`
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> (it diverged to the `IStreamingDecoder`/WebCodecs seam precisely because per-segment `decodeAudioData` is
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> architecturally wrong for Opus — see `IStreamingDecoder.ts`), and its seek is accurate and shipping. The
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> body below is rewritten to the two-path reality. **The headline is unchanged:** bound client memory to a
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> sliding window regardless of stream length, for the canonical 1 GB mix, across both delivery formats.
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---
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@@ -31,18 +58,34 @@ Bound the **client memory** a playing track consumes to a small, configurable fo
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**independent of total stream length** — so a 1 GB+ DJ MIX (Phase 9 `Mix` medium: a single long track)
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plays without the whole decoded PCM accumulating in the browser.
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**The defect, stated precisely.** The network path already streams in adaptive 16–64 KB chunks
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(`StreamingAudioPlayerService.StreamAudioWithEarlyPlayback`) — that part is fine. The accumulation is on
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the **decode side**: `PlaybackScheduler` holds `private buffers: AudioBuffer[]` and **never evicts**
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("Supports pause/resume/seek by **retaining all buffers**" — its own doc comment). Every 64 KB segment
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the `StreamDecoder` decodes is pushed via `addBuffer()` and kept for the life of the track. Decoded PCM
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is **larger than the compressed-or-raw source** in memory (Web Audio `AudioBuffer` is 32-bit float per
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sample per channel — a 16-bit stereo WAV roughly **doubles** in size once decoded), so a 1 GB WAV becomes
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~2 GB of retained `AudioBuffer` float data. That is the OOM.
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**The defect, stated precisely — and it now has two faces, one shared.** The network path already
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streams in adaptive 16–64 KB chunks (`StreamingAudioPlayerService.StreamAudioWithEarlyPlayback`) — that
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part is fine. The accumulation is on the **decode side**, and Phase 18 split the decode side into two
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pipelines that both terminate at the same sink:
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**One-line framing:** today the player decodes the whole track into memory and keeps it; Phase 21 makes
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it keep only a sliding forward window and discard what has already played, refilling on demand from the
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Range primitive it already uses for seek.
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- **The shared sink (both paths) — the unbounded scheduler.** `PlaybackScheduler` holds
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`private buffers: AudioBuffer[]` and **never evicts** ("Supports pause/resume/seek by **retaining all
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buffers**" — its own doc comment). Both decode paths call `scheduler.addBuffer()` (via
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`AudioPlayer.processFormatChunk` for WAV/MP3/FLAC and `processOpusChunk` for Opus); nothing is ever
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removed. Decoded PCM is **larger than the source** in memory (Web Audio `AudioBuffer` is 32-bit float
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per sample per channel — a 16-bit stereo WAV roughly **doubles** once decoded; Opus decodes to the same
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48 kHz float PCM regardless of how few bytes the *compressed* stream was). So a 1 GB WAV becomes ~2 GB
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of retained float, **and a low-data Opus mix becomes the same ~2 GB of decoded float once played** —
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the compressed transfer is small, but the *decoded* footprint is identical. The scheduler is the OOM for
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both. **This is the §3.1 root cause, unchanged from the original spec — it just now afflicts two
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producers.**
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- **The Opus-only second locus — upstream decode-ahead.** The Opus path accumulates *before* the
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scheduler too: the WebCodecs `AudioDecoder` work queue (`decodeQueueSize`), the `decodedQueue:
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AudioData[]` awaiting conversion, and the `OggDemuxer`'s partial-page state. Bounding the scheduler
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alone does not bound these — they fill from the same C# `ReadAsync` loop, so they need their own
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back-pressure (on the *demuxer/decoder feed*), not only the read loop's. WAV has no equivalent
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upstream queue (its `StreamDecoder` decodes synchronously into the scheduler), so this is genuinely
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Opus-specific.
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**One-line framing:** today the player decodes the whole track into memory and keeps it — true for both
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formats; Phase 21 makes it keep only a sliding forward window and discard what has already played,
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refilling on demand from the Range primitive both paths already use for seek (WAV via `IFormatDecoder`,
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Opus via the live index-driven `resolveOpusByteOffset`).
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---
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@@ -60,36 +103,51 @@ docs. This phase **modifies that seam** — so the contract it must preserve is
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- **C2 — Playback start latency unchanged.** Today playback starts as soon as a configurable minimum
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buffer count is queued (header-derived duration, not full-file). The window model must keep first-audio
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latency at parity — bounding memory must not reintroduce a fetch-then-play stall.
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- **C3 — The format-decoder abstraction is untouched.** `IFormatDecoder` owns all format-specific
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byte math; `AudioPlayer.createFormatDecoder` already dispatches on `Content-Type` (WAV/MP3/FLAC
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decoders all wired today — verified 2026-06-23; an `OpusFormatDecoder` joins them in Phase 18).
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Windowing lives in the
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**format-agnostic** layer (`PlaybackScheduler` eviction + `StreamDecoder`/player refill
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orchestration); it must add **no** format-specific branches. A future wired MP3/FLAC decoder inherits
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windowing for free.
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- **C3 — Neither decoder seam's contract is forked; windowing lives in the shared layer plus a thin
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per-seam hook.** There are two decoder seams as of Phase 18: `IFormatDecoder` (WAV/MP3/FLAC, owns
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format byte math; `AudioPlayer.createFormatDecoder` dispatches on `Content-Type`) and `IStreamingDecoder`
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(Opus, the WebCodecs pipeline; selected in `initializeStreaming` when the content type is
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`audio/ogg`/`audio/opus` and a sidecar is present). **The eviction half of windowing is fully shared** —
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it lives in `PlaybackScheduler`, which both seams feed identically via `addBuffer`, so eviction adds
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**zero** format branches. **The back-pressure / decode-ahead half is necessarily seam-aware** — the WAV
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path back-pressures the C# `ReadAsync` loop; the Opus path must additionally bound the WebCodecs
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decode-ahead and the `decodedQueue` (§3.1). Express that as a **small uniform signal** ("the scheduler is
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full, stop producing") that each decode path honors in its own way, rather than a windowing controller
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that reaches into either decoder's internals. The goal the original C3 stated still holds — no
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format-specific logic leaking into the *scheduler* — but the spec now acknowledges the producer side has
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two shapes, not one.
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- **C4 — Read-only playback only.** This is a memory-management change, not a UX change. No new
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user-visible control, no change to seek/transport semantics beyond what the listener already
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experiences. Seek must still feel identical.
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- **C5 — Must window both delivery formats (WAV lossless AND Opus low-data).** Byte↔time mapping for
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refill is exact and cheap for WAV (CBR: `byteRate` from the header). **Phase 18 (Opus) is sequenced
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before this phase and is the concrete VBR driver here** — and its mapping is **also exact**, but by a
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different mechanism: an Ogg Opus 320 stream has no linear time↔byte relationship, so
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`OpusFormatDecoder.calculateByteOffset` resolves via a **precomputed seek index** (granule→byte, built at
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transcode; Phase 18 §3.4a), a binary search that returns the exact page offset — **not** an approximate
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page interpolation. (An earlier draft of this invariant said "approximate"; the Phase 18 seek-model
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resolution, Daniel 2026-06-23, made Opus seeking accurate. Corrected here.) The window machinery must
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express refill purely in terms of the decoder's existing `calculateByteOffset`, so the same code windows
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WAV (via `byteRate`) and Opus (via the index) — **no WAV-special-cased offset math in the window layer**,
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and no approximation for either. A window that opens away from byte 0 must also prepend the decoder's
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retained/sidecar setup header (Phase 18 §3.4a B) — the format-agnostic refill path already routes
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continuations through the decoder's header-carry, so this comes for free. (MP3/FLAC decoders are already
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wired in the registry too — the registry dispatches on content-type today; an `OpusFormatDecoder` joins
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them in Phase 18.)
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- **C6 — No regression to the single-instance JS decoder concurrency guarantees.** The current code is
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careful that only one streaming loop touches the single JS `StreamDecoder` at a time
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(`DrainActiveStreamingTaskAsync`, the `_streamingCancellation` identity dance). Windowed refill
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introduces *more* mid-stream fetches; it must route through the **same** drain/cancellation discipline,
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not around it.
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- **C5 — Window both decode paths without forking the scheduler/seam, reusing the live index-driven
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seek for refill.** Both delivery formats must be windowed, and the byte↔time mapping each refill needs is
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**already accurate and already shipping** for both:
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- **WAV/MP3/FLAC** — `IFormatDecoder.calculateByteOffset` (CBR `byteRate` for WAV; the MP3/FLAC seek
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accelerators for those), reached through `StreamDecoder.calculateByteOffset` / `AudioPlayer.seekBeyondBuffer`.
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- **Opus** — `resolveOpusByteOffset(activeOpusSidecar, t)` (binary search the precomputed granule→byte
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seek index in `OpusSeekData`), returning an exact page-start offset **and** a `landingTimeSeconds` for
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the decoder's frame-accurate lead-trim. This is **accurate, not approximate, and landed in Phase 18.**
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Phase 21 does **not** build either mapping. The window's refill trigger calls *whichever resolver the
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active path already uses* — for Opus, the **same** `resolveOpusByteOffset` an explicit listener seek
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calls (the live path in `AudioPlayer.seekBeyondBuffer`), so windowed refill is literally "a seek the
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listener didn't initiate." A window opening away from byte 0 decodes correctly on the Opus path because
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the setup header (`OpusHead`/`OpusTags`) is already cached from the sidecar and re-applied by
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`reinitializeForRangeContinuation` (Phase 18 §3.4a B); the WAV path re-applies its retained header the
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same way. **No new offset math, no approximation, no header re-fetch — all reused.** The invariant is
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therefore *not* "make refill format-agnostic" (the two paths legitimately resolve offsets through
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different code); it is **"reuse the live seek of each path verbatim; add only the eviction and the
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refill *trigger*, never a second seek mechanism."**
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- **C6 — No regression to the single-writer decoder concurrency guarantee — now covering both decoders.**
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The C# loop is careful that only one streaming task feeds the active JS decoder at a time
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(`DrainActiveStreamingTaskAsync`, the `_streamingCancellation` identity dance in
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`StreamingAudioPlayerService`). This matters *more* for Opus: the WebCodecs `AudioDecoder` is stateful
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and async — a `reset()`+`configure()` on a range-continuation (`reinitializeForRangeContinuation`) racing
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a still-draining `push()` from a stale loop would corrupt inter-frame state, not merely deliver a wrong
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buffer. Windowed refill introduces *more* mid-stream fetches against whichever decoder is active; every
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one must route through the **same** drain/cancellation discipline, not around it. The discipline is
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already decoder-agnostic at the C# layer (it cancels the loop, not the decoder), so this is a "keep using
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it" invariant — but it is the rule most likely to be violated by a naive Opus refill, and is the hardest
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failure to diagnose, so it is called out as a hard invariant for both paths.
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- **C7 — The Mix visualizer's data source is independent and must stay that way.** The Phase 10/12
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WebGL2 lava visualizer renders from a **preprocessed high-res waveform datum** fetched per-track
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(`GET api/track/{entryKey}/waveform/high-res`), **not** from live decoded PCM. Confirmed: evicting
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@@ -103,8 +161,10 @@ docs. This phase **modifies that seam** — so the contract it must preserve is
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### 3.0 The mental model
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A track's audio is a byte range `[0, fileLength)` on disk. At any moment the listener is at playback
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position `P` (seconds → byte offset via the format decoder). The player should hold decoded
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`AudioBuffer`s only for a bounded window roughly `[P - back, P + ahead]`:
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position `P` (seconds → byte offset via the active path's resolver — `IFormatDecoder.calculateByteOffset`
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for WAV/MP3/FLAC, `resolveOpusByteOffset` over the seek index for Opus). The player should hold decoded
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`AudioBuffer`s only for a bounded window roughly `[P - back, P + ahead]` — and, on the Opus path, keep the
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upstream WebCodecs decode queue near-empty too (§3.1):
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- **forward fill (`ahead`)** — enough decoded lookahead that playback never starves (covers the existing
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500 ms scheduler lookahead plus network jitter headroom);
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@@ -119,42 +179,64 @@ position `P` (seconds → byte offset via the format decoder). The player should
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This is a **ring/sliding-window buffer keyed on playback position**, driven by high/low-water marks —
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the standard bounded-producer/bounded-consumer pattern, transplanted onto the decode→schedule seam.
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### 3.1 Why this is a generalization of seek-beyond-buffer, not a new mechanism
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### 3.1 Why refill is a generalization of seek-beyond-buffer, not a new mechanism — for both paths
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The seek-beyond-buffer path already does **every primitive** the window needs, just triggered manually
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and one-shot:
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The seek-beyond-buffer path already does **every refill primitive** the window needs, just triggered
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manually and one-shot. As of Phase 18 each primitive has a WAV branch and an Opus branch, both live:
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| Window operation | Existing seek-beyond-buffer machinery it reuses |
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|-------------------------------|-----------------------------------------------------------------------------------|
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| Discard buffers, keep offset | `PlaybackScheduler.clearForSeek()` + `setPlaybackOffset()` (clears buffers, retains the absolute-time anchor) |
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| Fetch from a byte offset | `TrackMediaClient.GetTrackMedia(key, byteOffset)` → `Range: bytes=X-` → 206 |
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| Decode a header-less body | `StreamDecoder.reinitializeForRangeContinuation(remainingByteLength)` |
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| Map time → byte offset | `StreamDecoder.calculateByteOffset()` → `IFormatDecoder.calculateByteOffset()` |
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| Single-loop safety on refetch | `_streamingCancellation` swap + `DrainActiveStreamingTaskAsync()` |
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| Window operation | WAV/MP3/FLAC machinery reused | Opus machinery reused (Phase 18, landed) |
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|-------------------------------|--------------------------------------------------------------------|--------------------------------------------------------------------------------------|
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| Discard buffers, keep offset | `PlaybackScheduler.clearForSeek()` + `setPlaybackOffset()` | *same* — the scheduler is shared |
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| Fetch from a byte offset | `TrackMediaClient` → `Range: bytes=X-` → 206 | *same* (with `?format=opus`) — the Range path is shared |
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| Map time → byte offset | `StreamDecoder.calculateByteOffset()` → `IFormatDecoder` | `resolveOpusByteOffset(activeOpusSidecar, t)` (index binary search → exact page) |
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| Decode a header-less body | `StreamDecoder.reinitializeForRangeContinuation(len)` | `OpusStreamDecoder.reinitializeForRangeContinuation(landingTime, target)` (demux/codec reset + lead-trim) |
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| Single-loop safety on refetch | `_streamingCancellation` swap + `DrainActiveStreamingTaskAsync()` | *same* — the C# discipline is decoder-agnostic |
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The difference is **eviction does not exist yet** (the scheduler only ever `clear()`s wholesale) and
|
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**refill is one-shot** (a seek, not a continuous low-water-triggered loop). So the new work is two
|
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seams: a *partial-evict* on the scheduler, and a *position-driven refill controller* on the player. The
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fetch/decode/offset plumbing is reused verbatim.
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The genuinely-new work, by path:
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- **Shared (both paths):** *partial eviction* on `PlaybackScheduler` (today it only ever `clear()`s
|
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wholesale), and a *position-driven refill trigger* (a continuous low-water loop, not a one-shot seek).
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- **WAV path:** *back-pressure on the C# `ReadAsync` loop* — stop reading the socket above the high-water
|
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mark, resume below low-water. WAV's `StreamDecoder` decodes synchronously into the scheduler, so the
|
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read loop is the *only* producer to throttle; pausing `ReadAsync` bounds it fully.
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- **Opus path:** *the same C# back-pressure, plus bounding the WebCodecs decode-ahead.* Throttling
|
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`ReadAsync` alone is **not sufficient** for Opus, because `OpusStreamDecoder.push()` is async and the
|
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WebCodecs `AudioDecoder` keeps its own internal work queue (`decodeQueueSize`) plus a `decodedQueue:
|
||||
AudioData[]` of decoded-but-not-yet-converted frames. The Opus producer must also stop *feeding the
|
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decoder* (stop demuxing/decoding new packets) when the scheduler is full, and resume below low-water —
|
||||
back-pressure on the **demuxer/decoder feed**, not only on the socket read. This is the one place the
|
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two paths' windowing genuinely diverges.
|
||||
|
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Everything else — the fetch, the offset resolution, the header-carry continuation, the single-loop
|
||||
cancellation safety — is **reused verbatim** on both paths. Phase 21 builds eviction + the refill trigger
|
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+ the (per-path) back-pressure; it builds **no** new fetch, offset, or seek mechanism.
|
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### 3.2 The three candidate directions
|
||||
|
||||
Per file convention the alternatives are recorded; the recommendation follows.
|
||||
|
||||
**Direction A — Sliding window on the existing single forward stream (recommended).**
|
||||
Keep the current model where the C# loop reads one forward HTTP stream and pumps chunks into the JS
|
||||
decoder. Add two things: (1) `PlaybackScheduler` gains *partial eviction* — drop buffers whose
|
||||
Keep the current model where the C# loop reads one forward HTTP stream and pumps chunks into the active
|
||||
JS decoder. Add three things: (1) `PlaybackScheduler` gains *partial eviction* — drop buffers whose
|
||||
absolute-time end is older than `P - back`, adjusting its index bookkeeping so `getCurrentPosition()`
|
||||
and scheduling stay correct against a buffer array that no longer starts at index 0; (2) a
|
||||
*back-pressure* signal — when forward decoded lookahead exceeds the high-water mark, the C# loop
|
||||
**pauses reading** the HTTP stream (stops calling `ReadAsync`) until playback drains it below low-water,
|
||||
then resumes. Memory is bounded by high-water + back-retain. Seek-back beyond the retained window falls
|
||||
through to the **existing** seek-beyond-buffer path unchanged.
|
||||
and scheduling stay correct against a buffer array that no longer starts at index 0 (**shared by both
|
||||
paths** — the scheduler is the common sink); (2) *back-pressure on the C# read loop* — when forward
|
||||
decoded lookahead exceeds the high-water mark, the C# loop **pauses reading** the HTTP stream (stops
|
||||
calling `ReadAsync`) until playback drains it below low-water, then resumes; (3) **for the Opus path
|
||||
only, back-pressure on the WebCodecs decode-ahead** — the producer also stops demuxing/decoding new
|
||||
packets when the scheduler is full, so the `AudioDecoder` work queue and `decodedQueue` do not balloon
|
||||
behind a throttled socket. Memory is bounded by high-water + back-retain on both paths. Seek-back beyond
|
||||
the retained window falls through to the **existing** seek-beyond-buffer path (the right one per format)
|
||||
unchanged.
|
||||
*Why recommended:* smallest change to the load-bearing seam; reuses the live forward stream (no extra
|
||||
connections in the common case); eviction and back-pressure are the only genuinely new mechanisms, and
|
||||
both are local (one to the scheduler, one to the read loop). Back-pressure via "stop reading the socket"
|
||||
is exactly how TCP flow control already wants to behave — pausing `ReadAsync` lets the kernel window
|
||||
close; we are not fighting the transport.
|
||||
connections in the common case); eviction and back-pressure are the only genuinely new mechanisms, all
|
||||
local (the scheduler; the read loop; for Opus, the demux/decode feed). Back-pressure via "stop reading
|
||||
the socket" is exactly how TCP flow control already wants to behave — pausing `ReadAsync` lets the kernel
|
||||
window close; we are not fighting the transport. The Opus decode-ahead bound is the one addition Phase 18
|
||||
forces, and it is local to the Opus producer.
|
||||
*Open question it raises (OQ6, new):* whether the two paths' back-pressure is driven by **one shared
|
||||
window controller** that exposes a "scheduler full / drained" signal both producers poll, or by **two
|
||||
parallel implementations** sharing only the eviction code. Recommend the **shared signal** — see §6 OQ6.
|
||||
|
||||
**Direction B — Discrete window segments, each its own Range fetch.**
|
||||
Treat the file as fixed-size byte segments (e.g. 4 MB). Hold N decoded segments around `P`; fetch the
|
||||
@@ -177,32 +259,41 @@ problem.
|
||||
wants containerized formats (fragmented MP4/WebM, or MP3/AAC elementary streams). The entire bespoke
|
||||
visualizer/spectrum graph is wired to the Web Audio `AudioContext`, not a `<media>` element. Adopting
|
||||
MSE is a **rewrite of the playback substrate**, not a windowing change. It *looked* like the real
|
||||
long-term answer once compressed delivery arrived — but Daniel has decided compressed delivery
|
||||
(**Phase 18 Opus**) will feed the **same bespoke graph** via the `IFormatDecoder` seam, so the
|
||||
compressed-delivery move that would have justified MSE happens *without* surrendering the graph. **The
|
||||
bespoke graph is a deliberate long-term commitment; MSE is rejected.** Direction A is therefore the
|
||||
permanent destination, not a stopgap that MSE will retire. Recorded as considered-and-declined.
|
||||
long-term answer once compressed delivery arrived — but compressed delivery (**Phase 18 Opus, now
|
||||
landed**) feeds the **same bespoke graph** via the WebCodecs `IStreamingDecoder` seam (parallel to the
|
||||
WAV `IFormatDecoder` seam, both terminating at the shared `PlaybackScheduler`), so the compressed-delivery
|
||||
move that would have justified MSE happened *without* surrendering the graph. Notably, Phase 18 chose a
|
||||
**WebCodecs `AudioDecoder`** for Opus rather than `decodeAudioData` — which is itself the "use the platform
|
||||
codec, keep the bespoke graph" move, but at the *decoder* granularity, not the *media-element* granularity
|
||||
MSE would impose. **The bespoke graph is a deliberate long-term commitment; MSE is rejected.** Direction A
|
||||
is therefore the permanent destination, not a stopgap that MSE will retire. Recorded as
|
||||
considered-and-declined.
|
||||
|
||||
### 3.3 Recommended direction: A, with B held as the documented fallback
|
||||
|
||||
Direction A is the smallest coherent change that hits the headline (bounded memory under a 1 GB stream)
|
||||
while honoring C1–C7. It keeps the live forward stream, reuses the seek-beyond-buffer path for the only
|
||||
genuinely random-access case (seek-back past the retained tail), and isolates the two new mechanisms.
|
||||
**The final architecture and the exact eviction/back-pressure API are staff-engineer's call at
|
||||
implementation** (per file convention); this spec fixes the *shape* and the invariants, not the method
|
||||
signatures.
|
||||
while honoring C1–C7. It keeps the live forward stream, reuses each path's seek-beyond-buffer machinery
|
||||
for the only genuinely random-access case (seek-back past the retained tail), and isolates the new
|
||||
mechanisms (eviction shared; back-pressure per path). **The final architecture and the exact
|
||||
eviction/back-pressure API are staff-engineer's call at implementation** (per file convention); this spec
|
||||
fixes the *shape* and the invariants, not the method signatures.
|
||||
|
||||
### 3.4 SOLID / road-not-taken rationale
|
||||
|
||||
- **SRP, preserved.** Eviction is a `PlaybackScheduler` concern (it already owns buffer storage); refill
|
||||
orchestration is a player-service/`StreamDecoder` concern (they already own the fetch loop); byte↔time
|
||||
math stays in `IFormatDecoder`. No responsibility crosses a boundary it does not already own.
|
||||
- **OCP, via C3/C5.** Windowing added in the format-agnostic layer means wiring MP3/FLAC later changes
|
||||
zero window code. The window expresses refill through `calculateByteOffset` — the one seam the
|
||||
decoders already implement.
|
||||
- **The seam stays single-writer (C6).** Every new refetch routes through the existing
|
||||
cancellation/drain discipline, so "only one loop touches the JS decoder" remains true. This is the
|
||||
rule most likely to be violated by a naive implementation and is called out as a hard invariant.
|
||||
- **SRP, preserved.** Eviction is a `PlaybackScheduler` concern (it already owns buffer storage, and is
|
||||
the single shared sink both decode paths feed); refill orchestration is a player-service concern (it
|
||||
already owns the C# fetch loop and the seek dispatch); byte↔time math stays where each path already keeps
|
||||
it — `IFormatDecoder.calculateByteOffset` for WAV/MP3/FLAC, `resolveOpusByteOffset` (over `OpusSeekData`)
|
||||
for Opus. No responsibility crosses a boundary it does not already own.
|
||||
- **OCP, via the shared sink + the live per-path seek.** Eviction added at the scheduler changes zero
|
||||
decoder code on either path. Refill reuses each path's *already-implemented* offset resolver — Phase 21
|
||||
adds no offset math to either seam. The one place windowing is not purely additive is the Opus
|
||||
decode-ahead bound (§3.1), which lives inside the Opus producer, not in the shared layer.
|
||||
- **The seam stays single-writer (C6) — for both decoders.** Every new refetch routes through the existing
|
||||
C# cancellation/drain discipline, so "only one loop feeds the active decoder" remains true for the WAV
|
||||
`StreamDecoder` and the stateful Opus `AudioDecoder` alike. This is the rule most likely to be violated
|
||||
by a naive Opus refill (a stale `push()` racing a `reset()`+`configure()`), and is called out as a hard
|
||||
invariant.
|
||||
- **Road not taken — eager full decode with a memory cap that just stops decoding.** Tempting (decode
|
||||
until you hit a byte budget, then stop) but it breaks playback of long tracks past the cap entirely —
|
||||
it bounds memory by *refusing to play the rest*, not by sliding. Rejected: it is a degradation, not a
|
||||
@@ -213,8 +304,15 @@ signatures.
|
||||
## 4. Use cases
|
||||
|
||||
- **UC1 — Play a 1 GB+ DJ MIX start to finish (the headline).** Memory stays bounded throughout; the
|
||||
listener experiences continuous playback identical to a short track.
|
||||
- **UC2 — Seek forward within a long track.** Already handled by seek-beyond-buffer; under windowing the
|
||||
listener experiences continuous playback identical to a short track. **Holds in both formats** — the
|
||||
lossless WAV mix (~2 GB decoded if unbounded) and the low-data Opus mix (small transfer, but the *same*
|
||||
~2 GB decoded float once played, so it needs windowing just as much; see §1).
|
||||
- **UC1-Opus — The same mix streamed as Opus, windowed.** The low-data win (Phase 18) shrinks the
|
||||
*transfer*; Phase 21 shrinks the *decoded footprint*. The two compound: a metered-connection listener on
|
||||
Opus gets both the small download and the bounded memory. Windowing the Opus path additionally bounds the
|
||||
WebCodecs decode-ahead and `decodedQueue`, not only the scheduler (§3.1).
|
||||
- **UC2 — Seek forward within a long track.** Already handled by seek-beyond-buffer (the right resolver per
|
||||
format — `IFormatDecoder` for WAV, the live `resolveOpusByteOffset` for Opus); under windowing the
|
||||
forward seek clears the window and refills at the target — no behavior change, now with eviction so the
|
||||
pre-seek region does not linger.
|
||||
- **UC3 — Seek back a few seconds.** Served from the back-retain window with **no** network refetch
|
||||
@@ -248,8 +346,11 @@ This phase touches the **same decoder/scheduler seam** as the deferred Phase 1.3
|
||||
- **1.5 Gapless (deferred).** Sample-accurate hand-off of the next track's first buffer at the current
|
||||
track's last buffer. Windowing changes *which* buffers are retained but not the hand-off mechanism;
|
||||
the only care point is that the current track's **final** window must not be evicted before the gapless
|
||||
boundary is scheduled. A minor invariant for whoever builds 1.5, not a blocker. Note 1.5's existing
|
||||
WAV-only caveat stands.
|
||||
boundary is scheduled. A minor invariant for whoever builds 1.5, not a blocker. **Phase 18 note:** the
|
||||
former "1.5 is WAV-only" caveat is superseded — Opus is live, and it has its own encoder pre-skip/priming
|
||||
(handled once by the WebCodecs decoder, see `OpusStreamDecoder.ts`), so a gapless Opus hand-off must
|
||||
respect the end-trim against the sidecar's authoritative total length. That is 1.5's problem to absorb,
|
||||
not Phase 21's; flagged so 1.5 inherits it.
|
||||
- **1.6 Track-skip on error (deferred).** *Windowing enlarges the error surface — call this out.* Today
|
||||
a fetch failure happens at load (one fetch) or at a user seek (one fetch). Windowed refill issues
|
||||
**mid-stream** fetches the listener did not initiate; one of those can fail at byte 700 M of a 1 GB
|
||||
@@ -260,9 +361,12 @@ This phase touches the **same decoder/scheduler seam** as the deferred Phase 1.3
|
||||
failure handling into Phase 21's acceptance criteria** (AC6) rather than leaving it entirely to 1.6 —
|
||||
it is created by this phase.
|
||||
- **1.7 Safari compatibility (deferred).** Windowing adds no new Safari-specific surface beyond what the
|
||||
streaming path already has. The one adjacency: more frequent `AudioContext` activity during refill
|
||||
should be checked against the older-Safari `webkitAudioContext` quirks when 1.7 is addressed — note it,
|
||||
do not block on it.
|
||||
streaming path already has. Two adjacencies, both Phase-18-introduced: (a) more frequent `AudioContext`
|
||||
activity during refill should be checked against older-Safari `webkitAudioContext` quirks; (b) the Opus
|
||||
path depends on **WebCodecs `AudioDecoder`**, whose Safari availability is narrower than `decodeAudioData`
|
||||
Ogg-Opus support — Phase 18's capability gate already falls a non-WebCodecs browser back to the lossless
|
||||
WAV path, so a Safari that can't run the Opus pipeline windows the *WAV* path (which has no decode-ahead
|
||||
locus, only the scheduler), i.e. the simpler windowing case. Note it; do not block on it.
|
||||
|
||||
---
|
||||
|
||||
@@ -294,22 +398,50 @@ These are policy calls with user-visible or resource trade-offs — flagged rath
|
||||
adopt MSE. The bespoke Web Audio decode→schedule graph stays — it is bespoke by deliberate choice, a
|
||||
long-term commitment, not a stopgap.** Daniel's rationale: the player is intentionally a custom
|
||||
graph, not an HTML `<media>` element; the compressed-delivery move that *would* have made MSE
|
||||
tempting is being met instead by **Phase 18 (Opus low-data path)** feeding the **same bespoke graph**
|
||||
through the `IFormatDecoder` seam — so compressed delivery arrives *without* surrendering the graph.
|
||||
Consequence for this phase: Direction A (the hand-rolled sliding window) is the destination, not a
|
||||
placeholder; invest in it as permanent machinery. It will window both the WAV and the Opus path
|
||||
(the sequencing note at the top). Direction C is recorded as **considered and declined** per file
|
||||
convention; kept visible so a future reader sees the road not taken and why.
|
||||
`[RESOLVED — bespoke graph retained; MSE rejected]`
|
||||
tempting was met instead by **Phase 18 (Opus low-data path, now landed)** feeding the **same bespoke
|
||||
graph** through the WebCodecs `IStreamingDecoder` seam (parallel to the WAV `IFormatDecoder` seam) — so
|
||||
compressed delivery arrived *without* surrendering the graph. Consequence for this phase: Direction A
|
||||
(the hand-rolled sliding window) is the destination, not a placeholder; invest in it as permanent
|
||||
machinery. It windows both the WAV and the Opus path (the header note). Direction C is recorded as
|
||||
**considered and declined** per file convention; kept visible so a future reader sees the road not taken
|
||||
and why. `[RESOLVED — bespoke graph retained; MSE rejected]`
|
||||
- **OQ6 — One window controller for both decode paths, or two? (NEW — raised by the Phase 18 two-path
|
||||
reality.)** Eviction is unambiguously shared (the scheduler is the one sink). Back-pressure is not: the
|
||||
WAV path throttles the C# `ReadAsync` loop; the Opus path must *also* throttle the WebCodecs
|
||||
decode-ahead (§3.1). Should there be **one window controller** exposing a uniform "scheduler full /
|
||||
drained" signal that both producers honor in their own way (recommended — keeps the *policy* — window
|
||||
sizes, water-marks, OQ1/OQ3 — in one place, with two thin per-path back-pressure hooks), or **two
|
||||
parallel windowing implementations** sharing only the eviction code (simpler per-path, but duplicates the
|
||||
water-mark logic and risks the two drifting)? Recommend the **shared controller + per-path hook**. This
|
||||
is more an architecture call than a product call — flagged for staff-engineer at implementation, with the
|
||||
recommendation as the default. `[staff-engineer call; recommendation: shared controller]`
|
||||
- **OQ7 — How does the Opus WebCodecs decode-ahead bound interact with scheduler eviction? (NEW; technical,
|
||||
for staff-engineer.)** The Opus producer has two queues to bound (the `AudioDecoder` work queue and
|
||||
`decodedQueue: AudioData[]`) *plus* the shared scheduler. The clean rule is "stop feeding the decoder when
|
||||
decoded-lookahead-in-the-scheduler exceeds high-water" — i.e. the **scheduler's** fill level is the
|
||||
single back-pressure signal, and the upstream Opus queues are kept near-empty by simply not demuxing
|
||||
ahead. The alternative (let the decoder run ahead into `decodedQueue` and bound *that* separately) adds a
|
||||
second budget to tune and a second eviction point. Recommend the former: **one fill signal (scheduler
|
||||
decoded-lookahead), drive both the read-loop pause and the demux/decode pause from it.** Confirm at
|
||||
implementation that the WebCodecs decoder tolerates being starved of input mid-stream and resumes cleanly
|
||||
(it should — it is fed packet-by-packet via `decode()`), and that `decodedQueue` is drained promptly so
|
||||
it never holds more than one `push()` worth. `[staff-engineer call; recommendation: single
|
||||
scheduler-fill signal]`
|
||||
|
||||
---
|
||||
|
||||
## 7. Acceptance criteria
|
||||
|
||||
- **AC1 (headline) — Bounded memory under a 1 GB stream.** Playing a 1 GB+ WAV mix start to finish, the
|
||||
browser tab's retained decoded-audio memory stays bounded to the configured window (not growing toward
|
||||
~2 GB). Verifiable via browser memory tooling: peak decoded-audio footprint is independent of track
|
||||
length and tracks the window-size policy, not the file size.
|
||||
- **AC1 (headline) — Bounded memory under a 1 GB stream, in BOTH formats.** Playing a 1 GB+ mix start to
|
||||
finish — **as lossless WAV and as low-data Opus** — the browser tab's retained decoded-audio memory
|
||||
stays bounded to the configured window (not growing toward ~2 GB). Verifiable via browser memory tooling:
|
||||
peak decoded-audio footprint is independent of track length and tracks the window-size policy, not the
|
||||
file size. The Opus case must be verified explicitly — its small *transfer* does not imply a small
|
||||
*decoded* footprint (§1), so "Opus already streams small" is **not** sufficient.
|
||||
- **AC1-Opus — The Opus upstream decode-ahead is bounded too (§3.1 / OQ7).** Under a long Opus stream, the
|
||||
WebCodecs decode queue and `decodedQueue` do not grow unboundedly behind the scheduler — back-pressure
|
||||
reaches the demux/decode feed, not only the scheduler. Verifiable: the upstream queues stay near-empty
|
||||
(one `push()` worth) regardless of stream length.
|
||||
- **AC2 — Playback-start latency at parity (C2).** First-audio latency for a track is unchanged from
|
||||
pre-windowing (within noise). Windowing does not introduce a fetch-then-play stall.
|
||||
- **AC3 — Continuous playback, no starvation.** A long mix plays edge to edge with no audible gaps,
|
||||
@@ -324,41 +456,70 @@ These are policy calls with user-visible or resource trade-offs — flagged rath
|
||||
"playing" with a starved scheduler). It must not silently hang.
|
||||
- **AC7 — The Mix visualizer is unaffected (C7).** With the lava visualizer running on a long mix, the
|
||||
visualizer renders identically (it reads the preprocessed datum, never the evicted buffers).
|
||||
- **AC8 — Single-decoder concurrency invariant holds (C6).** Under rapid seek + refill activity, no
|
||||
interleaved `ProcessStreamingChunk` calls corrupt the single JS decoder (the existing drain/cancel
|
||||
discipline still governs every fetch).
|
||||
- **AC8 — Single-writer decoder concurrency invariant holds (C6) — both decoders.** Under rapid seek +
|
||||
refill activity, no interleaved `ProcessStreamingChunk` / `push` calls corrupt the active decoder — the
|
||||
existing drain/cancel discipline still governs every fetch. **For Opus this is stricter:** no stale
|
||||
`push()` may land against the WebCodecs `AudioDecoder` across a `reinitializeForRangeContinuation`
|
||||
reset+reconfigure (which would corrupt inter-frame state, not just a buffer). Verify under a rapid
|
||||
seek-storm on an Opus mix specifically.
|
||||
|
||||
---
|
||||
|
||||
## 8. Wave decomposition
|
||||
|
||||
**Decomposition choice: split by *concern* (eviction → back-pressure → seek-back refill → validate), not
|
||||
by *path* (WAV-track vs Opus-track).** Rationale: the eviction concern (21.1) is genuinely shared — the
|
||||
scheduler is the one sink both paths feed — so a path-split would duplicate the hardest correctness work or
|
||||
arbitrarily assign it to one track. The concern spine keeps that shared work as a single cold-start wave
|
||||
and lets the *one* genuinely path-divergent concern (back-pressure, 21.2) carry an explicit two-track
|
||||
split *inside* the wave rather than fracturing the whole phase. This also matches how the seek-back refill
|
||||
(21.3) reuses each path's already-live seek — it is one concern (window-miss → refetch) with a per-path
|
||||
resolver underneath, not two features. The spine is unchanged from the original spec; the mechanisms
|
||||
inside 21.2 and 21.3 are made correct for both paths.
|
||||
|
||||
Dependency shape: `21.1 → 21.2 → 21.3`, with `21.4` validating the whole. 21.1 is the cold-start
|
||||
prerequisite and the load-bearing change; the rest layer on it.
|
||||
|
||||
- **21.1 — Partial eviction in `PlaybackScheduler` (cold-start; the load-bearing change).** Give the
|
||||
scheduler the ability to drop already-played buffers and keep its position/index bookkeeping correct
|
||||
against a buffer array that no longer begins at absolute time 0 (today `getCurrentPosition`,
|
||||
`playFromPosition`, and the scheduling loop all assume `buffers[0]` is the track start). This is the
|
||||
hardest correctness work in the phase — the time-anchor math must stay exact through eviction. No
|
||||
refill yet; with eviction alone and the forward read loop unchanged, this is provably memory-bounded
|
||||
for the *played* region. **Independent of the §6 open questions** — it can begin immediately; the
|
||||
window *sizes* (OQ1/OQ3) are parameters fed in later. Settled and cold-start.
|
||||
- **21.2 — Back-pressure on the forward read loop (the bound on the *unplayed* region).** Make the C#
|
||||
`StreamAudioWithEarlyPlayback` loop stop calling `ReadAsync` when forward decoded lookahead exceeds the
|
||||
high-water mark, and resume below low-water. Together with 21.1, this bounds *both* the played and
|
||||
unplayed sides — the full memory guarantee (AC1). Must route resume/pause through the existing
|
||||
cancellation-safe single-loop discipline (C6). **Depends on 21.1** (eviction must exist so the drained
|
||||
region is reclaimed, not merely un-read).
|
||||
- **21.3 — Seek-back-past-window refill (close the random-access case).** Wire UC4 — when a backward
|
||||
seek lands earlier than the retained tail, refetch via the existing seek-beyond-buffer Range path
|
||||
pointed at the earlier offset, and the minimal AC6 refill-failure handling. Mostly **reuse** of the
|
||||
landed seek path; the new work is the trigger (window-miss detection) and the clean-failure path.
|
||||
**Depends on 21.1 + 21.2** (needs the window boundaries they define).
|
||||
- **21.4 — Validation pass against the 1 GB target (acceptance).** Exercise AC1–AC8 against a real 1 GB+
|
||||
mix: memory profiling (AC1), latency parity (AC2), edge-to-edge playback (AC3), the seek matrix
|
||||
(AC4/AC5), induced refill failure (AC6), visualizer-running (AC7), and rapid-seek concurrency (AC8).
|
||||
Largely test/measurement; any break is likely a tuning fix in the 21.1 anchor math or the 21.2
|
||||
water-marks. **Depends on 21.1–21.3.**
|
||||
- **21.1 — Partial eviction in `PlaybackScheduler` (cold-start; the load-bearing change; SHARED by both
|
||||
paths).** Give the scheduler the ability to drop already-played buffers and keep its position/index
|
||||
bookkeeping correct against a buffer array that no longer begins at absolute time 0 (today
|
||||
`getCurrentPosition`, `playFromPosition`, and the scheduling loop all assume `buffers[0]` is the track
|
||||
start). This is the hardest correctness work in the phase — the time-anchor math must stay exact through
|
||||
eviction. Because both decode paths feed the scheduler identically via `addBuffer`, **eviction is written
|
||||
once and serves both** — no per-path branch. No refill yet; with eviction alone and the forward producers
|
||||
unchanged, this is provably memory-bounded for the *played* region on both paths. **Independent of the §6
|
||||
open questions** — it can begin immediately; the window *sizes* (OQ1/OQ3) are parameters fed in later.
|
||||
Settled and cold-start.
|
||||
- **21.2 — Back-pressure (the bound on the *unplayed* region) — two tracks, one signal.** Bound the
|
||||
not-yet-played decoded audio by stopping production above a high-water mark and resuming below low-water,
|
||||
driven by the scheduler's decoded-lookahead fill (OQ7). The fill *signal* is shared; the *throttle* has
|
||||
two sites because Phase 18 gave the two paths different producers:
|
||||
- **21.2a — C# read-loop back-pressure (serves both paths).** Make `StreamAudioWithEarlyPlayback` stop
|
||||
calling `ReadAsync` above high-water and resume below low-water. Routes resume/pause through the
|
||||
existing cancellation-safe single-loop discipline (C6). For the WAV path this is *sufficient* (its
|
||||
`StreamDecoder` decodes synchronously into the scheduler).
|
||||
- **21.2b — Opus decode-ahead back-pressure (Opus path only).** Additionally stop demuxing/decoding new
|
||||
packets when the same fill signal is over high-water, so the WebCodecs decode queue and `decodedQueue`
|
||||
do not balloon behind a throttled socket (§3.1, OQ7). This is the one mechanism with no WAV analogue.
|
||||
Confirm the WebCodecs decoder resumes cleanly after being starved of input mid-stream.
|
||||
Together with 21.1 this bounds *both* the played and unplayed sides on *both* formats — the full memory
|
||||
guarantee (AC1 + AC1-Opus). **Depends on 21.1** (eviction must exist so the drained region is reclaimed,
|
||||
not merely un-read). Per OQ6, 21.2a and 21.2b ideally share one window controller exposing the fill
|
||||
signal; the recommendation is the shared controller + two thin hooks.
|
||||
- **21.3 — Seek-back-past-window refill (close the random-access case; one concern, per-path resolver).**
|
||||
Wire UC4 — when a backward seek lands earlier than the retained tail, refetch via the existing
|
||||
seek-beyond-buffer path pointed at the earlier offset, **using whichever resolver the active path already
|
||||
ships** (`IFormatDecoder`/`StreamDecoder.calculateByteOffset` for WAV; the live
|
||||
`resolveOpusByteOffset` + `OpusStreamDecoder.reinitializeForRangeContinuation` for Opus) — plus the
|
||||
minimal AC6 refill-failure handling. Mostly **reuse** of the landed seek paths; the new work is the
|
||||
trigger (window-miss detection) and the clean-failure path, both format-agnostic. **Depends on 21.1 +
|
||||
21.2** (needs the window boundaries they define).
|
||||
- **21.4 — Validation pass against the 1 GB target, BOTH formats (acceptance).** Exercise AC1–AC8 against a
|
||||
real 1 GB+ mix **streamed as WAV and as Opus**: memory profiling (AC1 both formats + AC1-Opus upstream
|
||||
queues), latency parity (AC2), edge-to-edge playback (AC3), the seek matrix (AC4/AC5), induced refill
|
||||
failure (AC6), visualizer-running (AC7), and rapid-seek concurrency (AC8 — including the Opus
|
||||
seek-storm). Largely test/measurement; any break is likely a tuning fix in the 21.1 anchor math, the
|
||||
21.2 water-marks, or the 21.2b Opus decode-ahead bound. **Depends on 21.1–21.3.**
|
||||
|
||||
---
|
||||
|
||||
@@ -366,18 +527,35 @@ prerequisite and the load-bearing change; the rest layer on it.
|
||||
|
||||
- Root `CLAUDE.md` "Streaming-first audio playback" / `CONTEXT.md §3.5` — the seam this phase modifies;
|
||||
the §2 invariants here restate its contract. Both flag it as the most load-bearing path.
|
||||
- `PLAN.md` Phase 4 (landed) / `COMPLETED.md` — the HTTP Range `bytes=X-` primitive this generalizes.
|
||||
- **`COMPLETED.md` Phase 18 — Opus Low-Data Streaming (landed 2026-06-23) — read this first.** The
|
||||
"as-built divergence" note records why Opus uses a **WebCodecs `AudioDecoder`** streaming pipeline
|
||||
(`IStreamingDecoder`) rather than the spec'd-and-replaced per-segment `decodeAudioData`/`IFormatDecoder`
|
||||
model. This is the two-path reality this phase reconciles to. `product-notes/phase-18-opus-low-data-streaming.md`
|
||||
is the design memo (note: its §3.4 `OpusFormatDecoder` framing predates the WebCodecs divergence — the
|
||||
*seek-index/sidecar* design in §3.4a is accurate and landed; the *decoder-shape* discussion was superseded
|
||||
by `IStreamingDecoder`).
|
||||
- `PLAN.md` Phase 4 (landed) / `COMPLETED.md` — the HTTP Range `bytes=X-` primitive this generalizes
|
||||
(now serving both `?format=lossless` and `?format=opus`).
|
||||
- `PLAN.md` Phase 1.3 / 1.4 / 1.5 / 1.6 / 1.7 — the deferred decoder/scheduler-seam features; §5 above
|
||||
reconciles each.
|
||||
reconciles each (1.5 and 1.7 updated for the Opus path).
|
||||
- `PLAN.md` Phase 9 — defines the `Mix` medium (single long track), the canonical 1 GB case.
|
||||
- `PLAN.md` Phase 10 / `product-notes/phase-10-mix-visualizer-lava-reframe.md` /
|
||||
`product-notes/phase-12-waveform-visualizer-generalization.md` — establishes the preprocessed
|
||||
per-track high-res waveform datum; the basis for C7 (visualizer does not read live PCM).
|
||||
- `DeepDrftPublic/Interop/audio/PlaybackScheduler.ts` — owns the unbounded `buffers: AudioBuffer[]`;
|
||||
21.1 lives here.
|
||||
- `DeepDrftPublic/Interop/audio/StreamDecoder.ts` — `reinitializeForRangeContinuation`,
|
||||
`calculateByteOffset`; the refill substrate.
|
||||
- `DeepDrftPublic/Interop/audio/PlaybackScheduler.ts` — owns the unbounded `buffers: AudioBuffer[]`, the
|
||||
**shared sink for both decode paths**; 21.1 (eviction) lives here.
|
||||
- `DeepDrftPublic/Interop/audio/AudioPlayer.ts` — the dispatch: `processFormatChunk` (WAV/MP3/FLAC) vs
|
||||
`processOpusChunk` (Opus), both calling `scheduler.addBuffer`; `seekBeyondBuffer`/`reinitializeFromOffset`
|
||||
branch per path; the place the refill trigger (21.3) and the fill-signal wiring (21.2) hook.
|
||||
- `DeepDrftPublic/Interop/audio/StreamDecoder.ts` + `IFormatDecoder.ts` — the WAV/MP3/FLAC refill substrate
|
||||
(`reinitializeForRangeContinuation`, `calculateByteOffset`).
|
||||
- `DeepDrftPublic/Interop/audio/IStreamingDecoder.ts` + `OpusStreamDecoder.ts` + `OggDemuxer.ts` +
|
||||
`OpusSidecar.ts` — the **Opus** path: the WebCodecs decode pipeline, the `decodeQueueSize`/`decodedQueue`
|
||||
upstream accumulation 21.2b must bound, and the live `resolveOpusByteOffset` /
|
||||
`reinitializeForRangeContinuation(landingTime, target)` seek 21.3 reuses. **`IStreamingDecoder.ts` is the
|
||||
seam the Opus windowing hooks into** (push/complete/reinitialize lifecycle).
|
||||
- `DeepDrftPublic.Client/Services/StreamingAudioPlayerService.cs` — the C# forward read loop
|
||||
(`StreamAudioWithEarlyPlayback`), the seek-beyond-buffer path (`SeekBeyondBuffer`), and the
|
||||
cancellation/drain discipline (C6); 21.2/21.3 live here.
|
||||
- `DeepDrftPublic.Client/Clients/TrackMediaClient.cs` — the Range-capable media fetch reused by refill.
|
||||
(`StreamAudioWithEarlyPlayback`, feeding *both* decoders), the seek-beyond-buffer path (`SeekBeyondBuffer`),
|
||||
and the cancellation/drain discipline (C6); 21.2a/21.3 live here.
|
||||
- `DeepDrftPublic.Client/Clients/TrackMediaClient.cs` — the Range-capable media fetch (with the `?format=`
|
||||
param) reused by refill on both paths.
|
||||
|
||||
Reference in New Issue
Block a user