nn::codec video decoders decode on their own thread, dav1d on frame threads: movies no longer stutter at a steady 60 fps

dm/games/0400486024DEC000/README.md

@@ -33,6 +33,7 @@ Measured on an M6 Mac with 16 GB, headless, on one walk with camera turns (`walk
 
 - Current on an M5 Pro MacBook Pro (16-inch, 20-core GPU, 24 GB, macOS 27.2, 2026-11-09), `kokiri-deck` from a deck autosave with the full library of chain `dedc9391c30b`, at full resolution (Dynamic resolution off), two runs a variant: in a window a locked 60 fps (59.8–60.0, frame p99 16.8–19.4 ms, GPU p50 10.2 ms). In fullscreen on its ProMotion screen it held 40 fps (39.6–40.1) at the same GPU time, with every present a 120 Hz refresh late and every other link tick skipped: [The 60 Hz link at 40 fps in fullscreen on a ProMotion screen](../../../docs/reference/frame-rate.md#the-60-hz-link-at-40-fps-in-fullscreen-on-a-promotion-screen). With the 120 Hz link there, 58.8–59.6 fps, frame p99 25.3 ms; with the screen held at its fixed 60 Hz mode, 60.0 fps, frame p99 16.9 ms, which fullscreen now switches to. MetalFX present upscaling to the 3456-wide fullscreen cost no measurable GPU time (59.4–59.7 fps). Resident about 10 GB, GPU allocated 11.2–11.4 GB; the prepare step took 7.3 s on a first start.
 - Current: the title and menu, a movie behind them, are a locked 60 fps (p50 16.67 ms, GPU span 15.6 ms).
+- Resolved: the title movie and the cutscene movies stuttered in small regular jerks at that steady 60 fps on a Mac that decodes AV1 with dav1d (M1, M2). The frames were on time and the movie's pictures were not: the player's `advance` (`main+0x3b61ea0`) found no new picture in 546 and 569 of about 2,900 frames of the title on an M2 Pro, and showed the last one again. Two causes, both general: [packets decoded inside the submission](../../../docs/reference/movies.md#nncodec-packets-decoded-inside-the-submission), on the player's one reader thread, which also gives the shown pictures back, and [dav1d one frame at a time](../../../docs/reference/movies.md#dav1d-decoded-one-frame-at-a-time) (15.4 ms a packet in the movie's heaviest five seconds, 122 ms the longest). After: 0 or 1 in 2,567 to 3,036 frames a run (eight runs of 54 s, headless, `DM_PROBE=main:3b61ed8,main:3b61f80` counting the failed and the good calls), and `DecodeAsync` returns in 0.1 ms at the median and 1.1 ms at the 99th percentile, from 1.9 and 120 ms. Open: not run on an M1 or M2 with four performance cores, nor on an iPad; a Mac with a hardware AV1 decoder (M3 on) decodes with VideoToolbox, where only the first cause applied, not measured.
 - Game speed: the game steps its time by a frame ratio, its base rate (60, or 30) / its int frame rate, whatever the frame took (`main+0x6e6cc4` on v131072), so frames longer than a vsync played in slow motion (seen by the user on a slower Mac; [issue 1375](https://github.com/seedds/nxnative/issues/1375)'s M1 Max ran the title at about 28 fps). With `fps_target 60` the ratio is the host's frame step × base / 60 ([A fixed frame step plays in slow motion on a slow Mac](../../../docs/reference/frame-rate.md#a-fixed-frame-step-plays-in-slow-motion-on-a-slow-mac)), a stub placed by its function's fingerprint ([`patches.py`](patches.py)). Mac runs on the M6 (2026-11-08, a test host on the libraries of chain `3ee493b2c3a4`): the user's play sessions held 60 fps with 2- and 3-vsync holds while areas loaded, game time 1.000 of real time by the host's count. That count is the stub's own; no run on a Mac slow enough to show the slow motion before and after.
 - Current: walking the village at the game's top internal resolution, 1536x864: a locked 60 fps, mean 16.67 ms over each settled window. Per 2,700 frames: 0-8 frames over 25 ms and 0-2 over 33 ms. Frame p95 17.8-18.9 ms with no window, as the game's own loop moves around its fence wait; in a window p95 17.8 ms, 3 over 25 ms and 5-16 over 18 ms per 600. GPU span p50 16.5 ms, summed GPU 15.8 ms, CPU 6 ms, about 101 passes a frame. The heavy stretch where the village opens (about 1,560 draws) holds 16.65-16.8 ms by lowering its resolution, then returns to full. The main pass used to sit at 763x429 at the same GPU time: [marked shaders tested depth late](../../../docs/reference/frame-rate.md#a-hosts-own-store-in-a-fragment-shader-moves-its-depth-test).
 - Before [pool shaders stopped counting as depth readers](../../../docs/reference/rendering.md#pool-shaders-taken-as-depth-readers): passes 118, 104, 219, 224 in a four-frame cycle, frame times 15, 15, 18, 18.5 ms, mean 16.9 ms. Half the frames rendered the reflection probe's faces with one draw a pass.
@@ -103,7 +104,7 @@ From an empty save: at about 45 s `A` (title), `A` (New Game), then the movie. F
 - Resolved in the log, to be eye-checked at the spots it showed: flat blue holes in the ground with grass and rocks floating over them (Kokiri Forest, the village floor, the Deku Tree) after an hour of play: [textures made for GPU use kept from their CPU rewrites](../../../docs/reference/nvn-objects.md#textures-made-for-gpu-use-kept-from-their-cpu-rewrites). The terrain tiles' height, blend and hole maps are rewritten from the CPU as tile slots are reused, and the dirty-page poll dropped every uncompressed one; with the fix, about 250 of them upload in the first 160 s of the Kokiri Forest autosave and a walk onto the village floor (M4 Pro), and the normal tiles the GPU draws stay, or become again, the GPU's.
 - Open, small differences from that same console frame: Navi's core has a harder edge and a narrower glow here (the bloom texture peaks at 0.44; the ball's HDR is about 0.9 with a tiny spot at 45); shadows are less blue, and the far grass about 1.4 times brighter. One frame of compressed video is weak evidence for either. The falling leaves look dark near the camera, not compared.
 - A red `texture type mismatch` on `9b310b3349825e9a` (a UI merge shader): a 3D texture left bound in a slot its active branch does not sample. Harmless so far.
-- `nn::codec AV1: busy (result 3603), a packet refused with 12 pictures waiting` (4 lines a run): the decoder's queue is full and the movie library retries, as it is written to ([a refusal is no fault](../../../docs/reference/movies.md#the-submission-ready-event-counted-as-packets)); movies play. It was a red line until then.
+- `nn::codec AV1: busy (result 3603), a packet refused with 0 pictures waiting for a released buffer and 12 packets to decode` (4 lines a run, at the title movie's start, where the reader sends ahead of the decoder): the decoder's queue is full and the movie library retries, as it is written to ([a refusal is no fault](../../../docs/reference/movies.md#the-submission-ready-event-counted-as-packets)); movies play. It was a red line until then.
 - The `pipeline archive` red line is [issue 342](https://github.com/seedds/nxnative/issues/342), a limit of this system build. `c1_full.tsv is stale` holds on partial libraries, which no full build has stamped.
 - The "Navi" name label in the Great Deku Tree scene was missing on an earlier chain and has not been checked since. Not played yet: the Deku Tree dungeon, combat, later areas. Sound opens with no red line; movies and speech were not listened to. Physics issues reported in PR 1299 were not seen on this route (walking, the ladder, the camera).
 - Resolved: dotted horizontal rows across the picture in play, in fog and light (GitHub issue 1537): the agl_ndsr_vr networks' HMMA calls outside a chain overwrote an accumulator a chain held ([An HMMA outside a chain overwrote the chain's accumulator](../../../docs/reference/shaders.md#an-hmma-outside-a-chain-overwrote-the-chains-accumulator)), since chain 23a1ea1db092; found by bisecting chains on the Kokiri Forest autosave (0f510fd5's chain clean, bd9f422d's not). Under the game's upscaler they had also grown into white blotches: [LDSM reads rows other lanes stored](../../../docs/reference/shaders.md#ldsm-reads-rows-other-lanes-stored).
@@ -205,5 +206,7 @@ From an empty save: at about 45 s `A` (title), `A` (New Game), then the movie. F
 - [Pixel shader inputs the mesh shader does not write](../../../docs/reference/shaders.md#pixel-shader-inputs-the-mesh-shader-does-not-write): the foliage point meshes' pipelines (pixel shaders reading generic attribute 5 that no mesh output writes).
 - [Mesh outputs as wide as their pixel shaders read](../../../docs/reference/shaders.md#mesh-outputs-as-wide-as-their-pixel-shaders-read): the foliage mesh `626fbf48041cb82b`, padded to 35,840 bytes of mesh output, past Metal's 32 KB.
 - [AV1 movies stop an M1 iPad with SIGILL in dav1d](../../../docs/reference/movies.md#av1-movies-stop-an-m1-ipad-with-sigill-in-dav1d): the title movie on an M1 iPad Pro.
+- [`nn::codec` packets decoded inside the submission](../../../docs/reference/movies.md#nncodec-packets-decoded-inside-the-submission): resolved, movies stuttering at a steady 60 fps; its player feeds the decoder and gives the shown pictures back on one thread.
+- [dav1d decoded one frame at a time](../../../docs/reference/movies.md#dav1d-decoded-one-frame-at-a-time): resolved, the title movie's heavy packets on an M2 Pro; and the drain that must go to its end.
 - [`devicectl` copies a large RomFS image through the Mac's memory](../../../docs/reference/packing.md#devicectl-copies-a-large-romfs-image-through-the-macs-memory): the 26.2 GB image's pushes to an iPad filled a 16 GB Mac's swap and failed; now sent over AFC.
 - [`devicectl`'s `--remove-existing-content` empties the app's whole container](../../../docs/reference/packing.md#devicectls---remove-existing-content-empties-the-apps-whole-container): the first complete copy of the image, deleted by the DLC step after it.

dm/games/040077201BE50000/README.md

@@ -55,7 +55,7 @@ Moving objects get their ambient light from eight values per object in a storage
 - A crash seen once in dozens of runs, in a run slowed by another game on the same GPU: the game's own wait at `main+0x2ecff24` (`ldarb` on a thread object at +0x285, in a loop that sleeps between reads) read an alias page just unmapped, right after `[mem] alias region mapped` fell. Not caused by the host's page protection, which does not unmap; whether the host unmaps earlier than Horizon would is not known.
 - The 12x12 cube the vertex shader mixes with the probe values holds 4 to 27 with `tex_flush_upload`, and read zeros without it.
 - [The guard band cull's](../../../docs/reference/shaders.md#a-guard-band-cull-in-every-vertex-shader-0x80d) real meaning, and the vertex output at `a[0x5c]` that 4,771 vertex shaders write and the translator drops (probably a shading rate, not checked).
-- `nn::codec VP9: busy (result 3603), a packet refused with 12 pictures waiting for a released buffer` (4 lines at the first movie, a red line until [a refusal was known to be no fault](../../../docs/reference/movies.md#the-submission-ready-event-counted-as-packets)); the movies seen play.
+- `nn::codec VP9: busy (result 3603), a packet refused with 12 pictures waiting for a released buffer` (4 lines at the first movie; since [the decoder has its own thread](../../../docs/reference/movies.md#nncodec-packets-decoded-inside-the-submission) the line also counts the packets still to decode, not seen on this game yet; a red line until [a refusal was known to be no fault](../../../docs/reference/movies.md#the-submission-ready-event-counted-as-packets)); the movies seen play.
 - A `pso_manifest.tsv` has not been recorded, so the first race compiles pipelines as it goes.
 - What `nvnTextureViewCompare`'s return value means is taken from its name.
 - City Trial played by hand, Road Trip, online, the base game, iOS: not tested.