diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58dda22..8236ffa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -46,6 +46,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
carry their gig log; instruments their gig count.
### Changed
+- **`GET /api/song/{f}?stems=1`** (new, opt-in) — returns the pack's playable stem
+ list (`[{id, url, default}]` + `full_mix_url`), the same list the highway's WS
+ `ready` sends. The stems plugin could only learn it from that WS message, which
+ arrives once the highway is already on screen — so it decoded and then copied the
+ whole song's PCM to its audio worklet with the player visible: over half a gigabyte
+ of memcpy in one frame for a 6-stem pack, a measured 698 ms freeze right as the
+ song-credits card appeared. With the list available at `song:loading` the plugin
+ does all of it before the highway is drawn. Built by calling `load_song` itself, so
+ it cannot drift from what the WS sends. Opt-in, so the library's metadata calls pay
+ nothing.
- **Folder library renders only the songs on screen** (#965) — a song list used to
render *every* song it held. On a flat 50,944-song library that was one `
`
with 50,938 children and ~1.3 **million** DOM nodes (~4.2 GB of renderer memory),
diff --git a/lib/routers/song.py b/lib/routers/song.py
index 50ed815..aa6644e 100644
--- a/lib/routers/song.py
+++ b/lib/routers/song.py
@@ -829,45 +829,49 @@ def post_song_gap_fill(filename: str, data: dict):
return {"ok": True, "written": additions, "skipped": skipped}
-def _playable_stems_payload(song_path, filename: str) -> dict:
+def _playable_stems_payload(filename: str, dlc) -> dict:
"""The playable stems (id/url/default) + full-mix URL for a sloppak.
- Byte-for-byte the same shape the highway's WS `ready` builds — same
- partition (the mixdown lifted out), same default resolution, same URL form —
- because the stems plugin now preloads from THIS and then has to agree with
- what the WS says a moment later, or it rebuilds the graph for nothing.
+ Why it exists: the stems plugin could only learn its stem list from the
+ highway's WS `ready`, which arrives once the highway is already up. So it
+ decoded, and then copied the whole song's PCM to its worklet, with the player
+ on screen — half a gigabyte of memcpy in one frame, ~700 ms, freezing the
+ venue video. Given the list at `song:loading` it can do all of that BEFORE the
+ highway appears, behind the loading overlay where a stall costs nothing.
- Why it exists: the stems plugin could only learn its stem list from the WS
- `ready`, which arrives once the highway is up. So it decoded, and then copied
- the whole song's PCM to its worklet, with the player already on screen — half
- a gigabyte of memcpy in one frame, ~700 ms, freezing the venue video (#…).
- Given the list at `song:loading` it can do all of that BEFORE the highway
- appears, behind the loading overlay where a stall costs nothing.
+ The list MUST be the same one the WS sends a moment later. If it is not, the
+ plugin preloads a graph and then throws it away and rebuilds — strictly worse
+ than not preloading. So this does not reimplement the WS's construction, it
+ calls THE SAME FUNCTION: load_song, whose LoadedSloppak already carries the
+ partitioned stems and the resolved full mix, and then builds the URLs exactly
+ as ws_highway does. Drift is impossible by construction rather than by
+ agreement — which matters, because `full_mix` in particular is not simply the
+ `full` stem: load_song falls back to the deprecated `original_audio:` key for
+ every pack written before feedpak 1.15.0, and reimplementing that (I did, at
+ first) silently dropped the pristine full mix for most real libraries.
Opt-in (`?stems=1`) so the library's own metadata calls — the hot path — pay
- nothing for it.
+ nothing for it. Non-sloppak sources (archives, loose folders) have no stems
+ to preload: load_song raises and we return the empty list.
"""
from urllib.parse import quote
try:
- meta = sloppak_mod.extract_meta(song_path)
+ loaded = sloppak_mod.load_song(filename, dlc, appstate.sloppak_cache_dir)
except Exception:
return {"stems": [], "full_mix_url": None}
q_fn = quote(filename, safe="")
- stems = [
- {
- "id": s["id"],
- "url": f"/api/sloppak/{q_fn}/file/{quote(s['file'])}",
- "default": bool(s.get("default", True)),
- }
- for s in (meta.get("stems") or [])
- if s.get("id") and s.get("file")
- ]
- full_file = meta.get("full_mix_file")
+
+ def _url(rel: str) -> str:
+ return f"/api/sloppak/{q_fn}/file/{quote(rel)}"
+
return {
- "stems": stems,
- "full_mix_url": f"/api/sloppak/{q_fn}/file/{quote(full_file)}" if full_file else None,
+ "stems": [
+ {"id": s["id"], "url": _url(s["file"]), "default": s["default"]}
+ for s in loaded.stems
+ ],
+ "full_mix_url": _url(loaded.full_mix) if loaded.full_mix else None,
}
@@ -911,7 +915,7 @@ async def get_song_info(filename: str, stems: int = 0):
if not stems:
return meta
extra = await loop.run_in_executor(
- None, _playable_stems_payload, song_path, filename)
+ None, _playable_stems_payload, filename, dlc)
return {**meta, **extra}
if cached:
diff --git a/lib/sloppak.py b/lib/sloppak.py
index d02d5e7..8f943e9 100644
--- a/lib/sloppak.py
+++ b/lib/sloppak.py
@@ -1278,15 +1278,7 @@ def extract_meta(path: Path) -> dict:
isinstance(sid, str) and sid
and isinstance(sfile, str) and sfile
):
- # `file` and `default` ride along so the REST song-info payload can
- # publish the same playable-stem list the WS `ready` message does —
- # the stems plugin needs it BEFORE the highway connects (see
- # get_song_info). Same helper as load_song, so they cannot disagree.
- valid_stems.append({
- "id": sid,
- "file": sfile,
- "default": stem_default_on(s.get("default", True)),
- })
+ valid_stems.append({"id": sid, "file": sfile})
# Partition exactly as load_song() does, for the same reason the library
# filter must not lie: `full` is the mixdown, not an instrument (spec §5.3).
# A separated pack that retains it would otherwise offer the user a "full"
@@ -1313,11 +1305,4 @@ def extract_meta(path: Path) -> dict:
"stem_count": stem_count,
# feedBack#129: per-stem filter needs the id list, not just count.
"stem_ids": stem_ids,
- # The PLAYABLE stems (id/file/default), partitioned exactly as load_song
- # does — the mixdown lifted out, never a layer. get_song_info turns these
- # into URLs so the stems plugin can start fetching and decoding on
- # `song:loading`, instead of waiting for the highway's WS `ready`.
- "stems": instrument_stems,
- # The mixdown, when the pack carries one (spec §5.3). Same reason.
- "full_mix_file": (_full or {}).get("file") or None,
}
diff --git a/tests/test_song_info_stems.py b/tests/test_song_info_stems.py
index d785902..dad4365 100644
--- a/tests/test_song_info_stems.py
+++ b/tests/test_song_info_stems.py
@@ -21,60 +21,52 @@ import yaml
import sloppak
-def _pak(tmp_path, stems, full=None, name="song.feedpak"):
+def _pak(tmp_path, stems, full=None, name="song.feedpak", original_audio=None):
manifest = {
"title": "T", "artist": "A", "duration": 10.0,
"arrangements": [],
- "stems": stems,
+ "stems": stems + ([full] if full else []),
}
- if full:
- manifest["stems"] = stems + [full]
+ if original_audio:
+ # The deprecated pre-1.15.0 shape: the mixdown lives outside `stems`.
+ manifest["original_audio"] = original_audio
p = tmp_path / name
with zipfile.ZipFile(p, "w") as z:
# Real packs carry manifest.yaml — a JSON manifest is not read at all.
z.writestr("manifest.yaml", yaml.safe_dump(manifest))
+ # _legacy_full_mix only returns a path that actually EXISTS on disk.
+ if original_audio:
+ z.writestr(original_audio, b"\0" * 16)
return p
-def test_extract_meta_carries_file_and_default(tmp_path):
- p = _pak(tmp_path, [
- {"id": "guitar", "file": "stems/guitar.ogg"}, # absent => on
- {"id": "vocals", "file": "stems/vocals.ogg", "default": False},
- {"id": "drums", "file": "stems/drums.ogg", "default": "off"}, # string form
- ])
- meta = sloppak.extract_meta(p)
- by_id = {s["id"]: s for s in meta["stems"]}
- assert by_id["guitar"]["default"] is True, "absent default means ON"
- assert by_id["vocals"]["default"] is False
- assert by_id["drums"]["default"] is False, "'off' must be honoured"
- assert by_id["guitar"]["file"] == "stems/guitar.ogg"
+def _payload(tmp_path, pak):
+ from routers.song import _playable_stems_payload
+ import appstate
+ cache = tmp_path / "cache"
+ cache.mkdir(exist_ok=True)
+ appstate.sloppak_cache_dir = cache
+ return _playable_stems_payload(pak.name, tmp_path)
-def test_the_mixdown_is_lifted_out_of_the_stem_list(tmp_path):
- # `full` is the mixdown, not a layer (spec 5.3). Listing it beside the
- # instruments would make the plugin play the whole song ON TOP of the stems.
- p = _pak(tmp_path,
- [{"id": "guitar", "file": "stems/guitar.ogg"},
- {"id": "bass", "file": "stems/bass.ogg"}],
- full={"id": "full", "file": "stems/full.ogg"})
- meta = sloppak.extract_meta(p)
- ids = [s["id"] for s in meta["stems"]]
- assert ids == ["guitar", "bass"], "the mixdown must not be a layer"
- assert meta["full_mix_file"] == "stems/full.ogg", "...but it must still be reachable"
+def _ws_payload(tmp_path, pak):
+ """Rebuild the WS `ready` stems payload exactly as ws_highway.py does."""
+ from urllib.parse import quote
+ cache = tmp_path / "cache"
+ cache.mkdir(exist_ok=True)
+ loaded = sloppak.load_song(pak.name, tmp_path, cache)
+ q = quote(pak.name, safe="")
+ return {
+ "stems": [
+ {"id": s["id"], "url": f"/api/sloppak/{q}/file/{quote(s['file'])}",
+ "default": s["default"]}
+ for s in loaded.stems
+ ],
+ "full_mix_url": f"/api/sloppak/{q}/file/{quote(loaded.full_mix)}" if loaded.full_mix else None,
+ }
-def test_a_single_full_pack_keeps_full_as_its_only_stem(tmp_path):
- # A pack whose ONLY stem is `full` is a single-mix pack: there is nothing to
- # be pristine against, so `full` stays playable and no mixdown is surfaced.
- p = _pak(tmp_path, [{"id": "full", "file": "stems/full.ogg"}])
- meta = sloppak.extract_meta(p)
- assert [s["id"] for s in meta["stems"]] == ["full"]
- assert meta["full_mix_file"] is None
-
-
-def test_default_resolution_is_shared_with_load_song(tmp_path):
- # The whole point: REST and the WS must not drift. Both go through
- # stem_default_on, so pin the helper's contract directly.
+def test_default_resolution_is_shared_with_load_song():
assert sloppak.stem_default_on(True) is True
assert sloppak.stem_default_on(False) is False
assert sloppak.stem_default_on("off") is False
@@ -85,47 +77,64 @@ def test_default_resolution_is_shared_with_load_song(tmp_path):
assert sloppak.stem_default_on(1) is True
-def test_rest_payload_matches_what_the_ws_would_build(tmp_path):
- """The safety property, pinned end to end.
+def test_rest_matches_the_ws_for_a_reserved_full_stem(tmp_path):
+ pak = _pak(tmp_path,
+ [{"id": "guitar", "file": "stems/guitar.ogg"},
+ {"id": "vocals", "file": "stems/vocals.ogg", "default": "off"}],
+ full={"id": "full", "file": "stems/full.ogg"},
+ name="Iron Maiden - Phantom.feedpak")
+ rest = _payload(tmp_path, pak)
+ assert rest == _ws_payload(tmp_path, pak)
+ assert [s["id"] for s in rest["stems"]] == ["guitar", "vocals"], "the mixdown is not a layer"
+ assert rest["full_mix_url"].endswith("stems/full.ogg")
+ assert rest["stems"][1]["default"] is False
- Rebuild the WS's stems_payload from load_song exactly as ws_highway does,
- and require the REST helper to produce the identical list.
+
+def test_rest_matches_the_ws_for_a_LEGACY_original_audio_pack(tmp_path):
+ """The one CodeRabbit caught, and the one that matters most in practice.
+
+ load_song falls back to the DEPRECATED `original_audio:` key when a pack has
+ no reserved `full` stem — which is every pack written before feedpak 1.15.0,
+ i.e. most of a real library. My first version of this payload reimplemented
+ the full-mix rule from extract_meta and silently returned None for them: REST
+ would say "no full mix" while the WS said there was one. The plugin would then
+ preload a graph WITHOUT the pristine mix and, because the signature still
+ matched, never rebuild — unity playback silently downgraded to the lossy
+ recombination.
+
+ The payload now calls load_song itself, so this cannot drift. Pinned anyway.
"""
- from urllib.parse import quote
- from routers.song import _playable_stems_payload
+ pak = _pak(tmp_path, [
+ {"id": "guitar", "file": "stems/guitar.ogg"},
+ {"id": "bass", "file": "stems/bass.ogg"},
+ ], name="Legacy Pack.feedpak", original_audio="original/full.ogg")
- p = _pak(tmp_path,
- [{"id": "guitar", "file": "stems/guitar.ogg"},
- {"id": "vocals", "file": "stems/vocals.ogg", "default": "off"}],
- full={"id": "full", "file": "stems/full.ogg"},
- name="Iron Maiden - Phantom.feedpak")
-
- cache = tmp_path / "cache"
- cache.mkdir()
- loaded = sloppak.load_song(p.name, tmp_path, cache)
-
- q_fn = quote(p.name, safe="")
- ws_stems = [
- {"id": s["id"], "url": f"/api/sloppak/{q_fn}/file/{quote(s['file'])}",
- "default": s["default"]}
- for s in loaded.stems
- ]
- ws_full = f"/api/sloppak/{q_fn}/file/{quote(loaded.full_mix)}" if loaded.full_mix else None
-
- rest = _playable_stems_payload(p, p.name)
-
- assert rest["stems"] == ws_stems, (
- "REST and the WS must publish the SAME stem list — a mismatch means the "
- "plugin preloads a graph and then rebuilds it, which is worse than not "
- "preloading at all"
+ rest = _payload(tmp_path, pak)
+ assert rest == _ws_payload(tmp_path, pak)
+ assert rest["full_mix_url"] is not None, (
+ "a pre-1.15.0 pack's full mix must survive — dropping it downgrades unity "
+ "playback to the lossy stem recombination, silently"
)
- assert rest["full_mix_url"] == ws_full
+ assert rest["full_mix_url"].endswith("original/full.ogg")
+
+
+def test_rest_matches_the_ws_for_a_single_full_pack(tmp_path):
+ # Its ONE stem IS the mixdown: nothing to be pristine against, so `full` stays
+ # the sole playable stem and no separate mixdown is surfaced.
+ pak = _pak(tmp_path, [{"id": "full", "file": "stems/full.ogg"}], name="Single.feedpak")
+ rest = _payload(tmp_path, pak)
+ assert rest == _ws_payload(tmp_path, pak)
+ assert [s["id"] for s in rest["stems"]] == ["full"]
+ assert rest["full_mix_url"] is None
def test_a_broken_pack_yields_an_empty_list_not_an_error(tmp_path):
- # Preloading is an optimisation. A pack we cannot read must fall back to the
+ # Preloading is an optimisation: an unreadable pack must fall back to the
# normal WS-driven path, never break the song-info request.
from routers.song import _playable_stems_payload
- bad = tmp_path / "bad.feedpak"
- bad.write_bytes(b"not a zip")
- assert _playable_stems_payload(bad, "bad.feedpak") == {"stems": [], "full_mix_url": None}
+ import appstate
+ cache = tmp_path / "cache"
+ cache.mkdir()
+ appstate.sloppak_cache_dir = cache
+ (tmp_path / "bad.feedpak").write_bytes(b"not a zip")
+ assert _playable_stems_payload("bad.feedpak", tmp_path) == {"stems": [], "full_mix_url": None}