docs: post-merge updates for PR #41 + #43

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## Unreleased
 
-- **refactor(rewriter): orthogonal HW-decode-text branch** (#40). The
+- **refactor(rewriter): orthogonal HW-decode-text branch** (#41). The
   HW-decode-text path now runs through `extractGraphFacts +
   composeBurn(burnSpec{vaResident:true, …})` — the same orthogonal core the
   SW-reshape (#39) and HW-decode-bitmap (#37) branches already use. The
@@ -21,7 +21,52 @@
   `-map [4]` / `-map [6]` is retargeted via the shared `retargetMapLabel`.
   Orthogonal parity harness 1369/1369 over the 1583-entry argv corpus, no
   drift; 4 of the original `reFilter*` regex zoo gone in v1.6.1, last 2 gone
-  now. No fork change.
+  now.
+
+- **fix(ffmpeg): sched start_prepare per-output sinkless gate** (#41, patch
+  `0122`). Patch `0120` skipped `dst_finished` allocation in `start_prepare()`
+  for any decoder marked `sink_less` — correct when the decoder has only a
+  sink-less side-channel output, broken when the decoder has BOTH a
+  sink-less side-channel AND a real OST consumer (the dual-consumer case
+  exercised when an argv keeps Plex's `-map <spec> -f null -codec ass
+  nullfile` decode-sink alongside `-map_inlineass <spec>`). In that case,
+  the OST output's `dst_finished` stayed NULL while `nb_dst=1`, and the
+  first `sch_dec_send` for the OST dereferenced `&dst_finished[0]` →
+  SIGSEGV in `dec1:0:srt`. Fix: move the sink-less gate INSIDE the
+  per-output loop so `dst_finished` is allocated for real outputs and only
+  the genuinely-unconnected outputs are skipped. Live-validated on
+  plex-test with a minimal lavfi+SRT gdb repro (pre-patch SIGSEGV →
+  post-patch clean decode, 2 packets read, 2 frames decoded).
+
+- **fix(rewriter): keep inlineass decode-sink for sidecar bindings** (#41).
+  Patch `0120`'s sink-less self-decode (via `ist_inlineass_add`) works for
+  embedded subtitle streams — they share the demuxer with main video,
+  which is pumped by the scheduler fast enough to feed the sink-less
+  decoder. For sidecar inputs (`-i temp-0.srt -map_inlineass 1:s:0`) the
+  separate sidecar demuxer thread has no other downstream consumer; the
+  scheduler chokes after the first packet (1 packet / 7 bytes from a
+  134 KiB SRT file, 0 frames decoded, libass track empty, subs render
+  blank). Fix: `stripInlineassDecodeSink` now gates on the `-map_inlineass`
+  binding's `file_idx == 0`. Sidecar bindings (`file_idx >= 1`) keep
+  Plex's emitted `-map <spec> -f null -codec ass nullfile` so the sidecar
+  demuxer has a real downstream consumer. Combined with patch `0122`
+  (above) the dual-consumer state is safe; sidecar SRT renders. Embedded
+  bindings still get the original `0120` strip (no extra null-mux
+  competing for the NFS read during pre-throttle buffer fill).
+
+- **refactor(rewriter): fold tryOptimizeRemux into Rewrite()** (#43). The
+  Optimize remux fast-path was a parallel function that re-ordered the
+  same helpers the main rewriter's tail already calls. Collapsed into one
+  path: detect `isRemux := isOptimizeRemux(args)` up-front, gate the
+  transcode block (decoder upgrade, init_hw_device, sub detection, filter
+  rewrite, encoder swap, SEI inject) and the VAAPI-only env writes (LIBVA
+  driver, inlineass-decode-sink strip) on `!isRemux`. Common tail (EAE
+  swap, manifest_name / segment_list / progressurl rewrites, loglevel /
+  nostats / env scrubs) runs unconditionally — already shared via
+  helpers, order-independent. Drops `decode:remux:<short>` and
+  `encode:copy(passthrough)` change tags (helper-emitted tags suffice).
+  Parity-validated on 720 corpus entries (real-prod + Optimize-sweep
+  matrix): 0 argv / env / progressurl divergence. Net −47 LOC.
 
 ## v1.6.1 — 2026-05-26
 

docs/PACED_SELF_DECODE.md

@@ -90,9 +90,16 @@ So the scheduler gains an explicit *sink-less* concept.
 ### `fftools/ffmpeg_sched.{c,h}`
 - `SchDec` gains `int sink_less;`.
 - New API `void sch_dec_set_sinkless(Scheduler *sch, unsigned dec_idx);`.
-- `start_prepare()`: skip the per-output "not connected to any sink" check when
-  `dec->sink_less` (the source check still applies — a sink-less decoder must
-  still be fed by the demuxer).
+- `start_prepare()`: skip the per-output "not connected to any sink" check
+  when `dec->sink_less` AND the output has `nb_dst == 0` (the source check
+  still applies — a sink-less decoder must still be fed by the demuxer).
+  **Per-output gate** — patch `0122` refines this from the original
+  whole-decoder `if (dec->sink_less) continue` which skipped `dst_finished`
+  allocation for ALL outputs of the decoder, including real OST consumers
+  in the dual-consumer case (sidecar SRT path where the rewriter keeps
+  Plex's null-mux decode-sink). The original variant SIGSEGV'd in
+  `sch_dec_send` on the first decoded frame when `dst_finished` was NULL
+  for the real output.
 - `sch_dec_send()`: when the target output has `nb_dst == 0`, `av_frame_unref`
   the frame and `return 0` (consumed, discarded) instead of falling through to
   the `AVERROR_EOF` result. Universally safe — only sink-less outputs ever have

docs/REWRITER.md

@@ -234,11 +234,21 @@ construction, and the OpenCL detour collapses into the canonical
   resolution tier below `render_height`. Static cues are unaffected. Same knob
   applies on the SW-reshape path (`composeBurn`'s `animatedTierDown` axis).
 - Plex's `-map_inlineass <spec>` is **kept** — it drives the libass feed.
-- Plex's `-map <spec> -f null -codec ass` decode-sink is **stripped**
-  (`stripInlineassDecodeSink`, gated on `-map_inlineass` still being present).
-  As of fork patch `0120` (v1.5.0) the `-map_inlineass` binding self-decodes
-  via a sink-less decoder paced by the demux, so the null-mux is redundant —
-  see `docs/PACED_SELF_DECODE.md`.
+- Plex's `-map <spec> -f null -codec ass` decode-sink is **conditionally
+  stripped** by `stripInlineassDecodeSink`, gated on (a) `-map_inlineass`
+  still being present AND (b) the binding's `file_idx == 0` (embedded sub
+  stream — shares the main demuxer with video). As of fork patch `0120`
+  (v1.5.0) the `-map_inlineass` binding self-decodes via a sink-less
+  decoder paced by the demux; for embedded subs the shared demuxer is
+  pumped by main video, so the null-mux is redundant and competes with the
+  NFS read during the pre-throttle buffer fill (the original reason to
+  strip it). For **sidecar bindings** (`file_idx >= 1`, e.g.
+  `-map_inlineass 1:s:0` pointing at a PMS-staged `temp-0.srt`) the
+  sidecar has its own demuxer thread with no other downstream consumer; the
+  scheduler chokes after the first packet and the binding sees zero cues.
+  There the decode-sink is **kept** so the sidecar demuxer has a real
+  consumer (patch `0122` makes the dual-consumer state safe for
+  `dst_finished` allocation). See `docs/PACED_SELF_DECODE.md`.
 - Plex's full `inlineass` node is passed through **verbatim** — including
   the styling keys `language`/`overrides`/`outline`/`shadow`. As of patch
   `0119` the fork's `inlineass` parses them (`overrides` →