From 3f4e69f7b803c15c06455800f8b176251154a2c5 Mon Sep 17 00:00:00 2001
From: Matthew Jackson <1085847+MattJackson@users.noreply.github.com>
Date: Tue, 25 Aug 2026 12:09:37 -0700
Subject: [PATCH] labels: add Fox dcx.xml vendor parser
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Older Fox discs ship a loose plain-XML manifest at
/BDMV/JAR/<id>/dcx.xml (root <dcx>) that names every feature stream's
language, editorial purpose and forced/SDH state in attributes — fully
parseable and previously unowned (2 Fox discs matched no parser, 11 were
mis-owned by the deluxe stub).

New src/labels/fox.rs:
  - detect(): loose dcx.xml under /BDMV/JAR/*/ (cheap dir walk), falling
    back to a com/foxbd/ jar central-directory prefix so newer Fox discs
    are attributed to Fox even though their bytecode form isn't decoded
    yet (Phase 2, sketched in-file).
  - parse(): scopes extraction to one <playlist name="feature"> element
    (the richest, to avoid merging regional 00800/00801 STN tables),
    reusing labels/xml.rs. audio type=rnib -> Descriptive, comment* ->
    Commentary; subtitle form=sdh -> Sdh, type=embed -> Forced; nested
    id="NN" -> 1-based per-type STN slot. High confidence.
  - Feature playlist id recorded via tracing::debug for now; dev's
    ParseResult has no feature_playlist field (that FeaturePlaylistHint
    slot lives on selection-hardening). An in-code note documents wiring
    it at reconciliation, matching paramount::parse.

Registered ahead of mpls_universal, alongside the High-confidence vendor
parsers; registry-order lock test updated.

Tests embed the real Life of Pi dcx.xml (/BDMV/JAR/05001), asserting the
00800 feature selection + id, all 11 audio labels (incl. the eng rnib
descriptive track) and 11 subtitle labels (sdh/forced/none), the
no-cross-playlist-merge scope rule, plus negative-detect cases.
---
 src/labels/fox.rs | 546 ++++++++++++++++++++++++++++++++++++++++++++++
 src/labels/mod.rs |  17 +-
 2 files changed, 559 insertions(+), 4 deletions(-)
 create mode 100644 src/labels/fox.rs

diff --git a/src/labels/fox.rs b/src/labels/fox.rs
new file mode 100644
index 00000000..5eab73c2
--- /dev/null
+++ b/src/labels/fox.rs
@@ -0,0 +1,546 @@
+//! Fox — loose `/BDMV/JAR/<id>/dcx.xml` plain-XML manifest.
+//!
+//! Older Fox authoring (e.g. *Life of Pi*, `/BDMV/JAR/05001/dcx.xml`) ships a
+//! human-readable XML manifest alongside the BD-J jar. Its root is `<dcx>`, and
+//! under `<disc>` it lists every playlist the disc plays. The main-feature
+//! playlists carry nested per-stream `<audio>`/`<subtitle>` elements naming
+//! language, editorial purpose and forced/SDH state outright — everything a
+//! label parser wants, in attributes, with no bytecode to walk.
+//!
+//! NOT A SPECIFICATION. `/BDMV/JAR/` is application-defined space, so this file
+//! is one authoring house's internal metadata that happens to press onto the
+//! disc. Every field meaning below was read off a real disc; treat an
+//! unfamiliar value as unknown rather than guessing.
+//!
+//! Confirmed schema (Life of Pi, `/BDMV/JAR/05001/dcx.xml`):
+//!
+//! ```xml
+//! <dcx>
+//!   <disc>
+//!     <playlist id="00001" lang="eng" name="topmenu"/>
+//!     ...
+//!     <playlist id="00800" lang="eng" name="feature" vers="1" durs="7628">
+//!       <audio id="01" lang="eng" type="feature"/>
+//!       <audio id="02" lang="eng" type="rnib"/>
+//!       <audio id="03" lang="spa" dial="lat" type="feature"/>
+//!       ...
+//!       <subtitle id="01" lang="eng" type="feature" form="sdh"/>
+//!       <subtitle id="02" lang="spa" dial="lat" type="embed"/>
+//!       ...
+//!       <subtitle id="11" lang="eng" type="text"/>
+//!       <properties> ...chapter marks... </properties>
+//!     </playlist>
+//!     <playlist id="00801" lang="jpn" name="feature" vers="1" durs="7628"> ... </playlist>
+//!   </disc>
+//! </dcx>
+//! ```
+//!
+//! Field meanings (read off the disc, not documented):
+//!   * `<audio type>`: `feature` = a normal program track; `rnib` = a
+//!     descriptive/narration track ("Royal National Institute of Blind People"
+//!     described-video), mapped to [`LabelPurpose::Descriptive`]. A `type`
+//!     containing "comment" maps to [`LabelPurpose::Commentary`].
+//!   * `<subtitle form>`: `sdh` marks a subtitles-for-the-deaf-and-hard-of-
+//!     hearing track ([`LabelQualifier::Sdh`]).
+//!   * `<subtitle type>`: `embed` marks a dedicated forced/embedded-subtitle
+//!     track ([`LabelQualifier::Forced`]); `feature`/`text` are full tracks.
+//!   * `id` on a nested stream is its 1-based STN slot WITHIN ITS TYPE
+//!     (audio ids 01..N, subtitle ids 01..N independently), matching the vendor
+//!     `stream_number` convention the ordinal binder in [`super::apply_labels`]
+//!     reads.
+//!
+//! The `<audio>`/`<subtitle>` elements are NESTED inside one feature playlist,
+//! so extraction is scoped to a single `<playlist name="feature">` element —
+//! never a document-wide `<audio>` scan, which would merge the regional
+//! `00800` (eng) and `00801` (jpn) tables into one and collide their slots.
+
+use super::{LabelPurpose, LabelQualifier, ParseResult, StreamLabel, StreamLabelType, xml};
+use crate::sector::SectorSource;
+use crate::udf::UdfFs;
+
+/// Detect a Fox disc.
+///
+/// Primary, cheap signal: a loose `dcx.xml` under some `/BDMV/JAR/<id>/`
+/// subdirectory — the manifest [`parse`] reads. Checked first because it is a
+/// directory walk with no sector reads.
+///
+/// Secondary signal: a `com/foxbd/` prefix in a top-level BD-J jar, which newer
+/// Fox discs (Deadpool et al.) carry instead of a loose `dcx.xml`. Recognising
+/// it attributes the disc to Fox rather than the generic deluxe stub even
+/// though [`parse`] cannot decode that bytecode form yet (see the Phase 2 note
+/// at the bottom of this file); such a disc detects here but yields no labels,
+/// so a lower-confidence parser still wins.
+pub fn detect(reader: &mut dyn SectorSource, udf: &UdfFs) -> bool {
+    if super::jar_file_exists(udf, "dcx.xml") {
+        return true;
+    }
+    super::jar::for_each_jar(reader, udf, |_, jar| {
+        super::jar::has_path_prefix(jar, "com/foxbd/").then_some(())
+    })
+    .is_some()
+}
+
+pub fn parse(reader: &mut dyn SectorSource, udf: &UdfFs) -> Option<ParseResult> {
+    let data = super::read_jar_file(reader, udf, "dcx.xml")?;
+    let text = std::str::from_utf8(&data).ok()?;
+
+    let labels = labels_from_dcx(text);
+    if labels.is_empty() {
+        return None;
+    }
+
+    // Surface the feature playlist's authoring id (e.g. "00800"). On this
+    // branch `ParseResult` carries no `feature_playlist` field — that
+    // `FeaturePlaylistHint` slot was added on the `selection-hardening` branch
+    // and does not exist on `dev` — so we record the id in the trace stream for
+    // now rather than clashing with that type. AT RECONCILIATION: populate
+    // `ParseResult.feature_playlist = Some(FeaturePlaylistHint { playlist_id:
+    // digits.parse(), filename: Some("<id>.mpls") })` here, exactly as
+    // `paramount::parse` does, so title selection can prefer the authoring
+    // feature over a size-inflated decoy.
+    if let Some(id) = feature_playlist_id(text) {
+        tracing::debug!(
+            target: "freemkv::labels",
+            fox_feature_playlist = %id,
+            "Fox dcx.xml feature playlist id (wire to FeaturePlaylistHint at reconciliation)",
+        );
+    }
+
+    // High confidence: the manifest is fully structured and every field
+    // extracted here has its meaning fixed by real discs.
+    Some(ParseResult::high(labels))
+}
+
+/// Build the stream labels from a `dcx.xml` document. Split out from [`parse`]
+/// so the schema mapping is unit-testable without a `SectorSource`/`UdfFs`.
+///
+/// Scoped to ONE feature playlist element (see the module note): the richest
+/// `<playlist name="feature">`. Its nested `<audio>`/`<subtitle>` children are
+/// the vendor's STN table for that title.
+fn labels_from_dcx(text: &str) -> Vec<StreamLabel> {
+    let Some(feature) = select_feature_playlist(text) else {
+        return Vec::new();
+    };
+
+    let mut labels = Vec::new();
+
+    // Audio streams.
+    let mut from = 0;
+    while let Some((s, e)) = xml::find_element(feature, "audio", from) {
+        let el = &feature[s..e];
+        from = e;
+        let Some(stream_number) = stream_number_from_id(&xml::attr(el, "id")) else {
+            continue;
+        };
+        let Some(language) = xml::attr(el, "lang") else {
+            continue;
+        };
+        let ty = xml::attr(el, "type")
+            .unwrap_or_default()
+            .to_ascii_lowercase();
+        labels.push(StreamLabel {
+            stream_id: None,
+            stream_number,
+            stream_type: StreamLabelType::Audio,
+            language: normalize_language(&language),
+            name: String::new(),
+            purpose: audio_purpose(&ty),
+            qualifier: LabelQualifier::None,
+            codec_hint: String::new(),
+            variant: String::new(),
+        });
+    }
+
+    // Subtitle streams.
+    let mut from = 0;
+    while let Some((s, e)) = xml::find_element(feature, "subtitle", from) {
+        let el = &feature[s..e];
+        from = e;
+        let Some(stream_number) = stream_number_from_id(&xml::attr(el, "id")) else {
+            continue;
+        };
+        let Some(language) = xml::attr(el, "lang") else {
+            continue;
+        };
+        let ty = xml::attr(el, "type")
+            .unwrap_or_default()
+            .to_ascii_lowercase();
+        let form = xml::attr(el, "form")
+            .unwrap_or_default()
+            .to_ascii_lowercase();
+        labels.push(StreamLabel {
+            stream_id: None,
+            stream_number,
+            stream_type: StreamLabelType::Subtitle,
+            language: normalize_language(&language),
+            name: String::new(),
+            purpose: LabelPurpose::Normal,
+            qualifier: subtitle_qualifier(&ty, &form),
+            codec_hint: String::new(),
+            variant: String::new(),
+        });
+    }
+
+    labels
+}
+
+/// Pick the disc's primary feature playlist element (the full `<playlist ...>
+/// ... </playlist>` text). Among all `<playlist name="feature">` elements —
+/// Fox presses one per regional variant (`00800` eng, `00801` jpn) — the one
+/// carrying the most `<audio>`/`<subtitle>` streams wins, ties to the first.
+///
+/// Returning ONE element is the whole point: each feature playlist is its own
+/// STN table with its own 1-based slot ids, so merging two would put two
+/// different streams on slot `01`. The richest table is the fullest label set
+/// and anchors to its matching title by language sequence in
+/// [`super::apply_labels`].
+fn select_feature_playlist(text: &str) -> Option<&str> {
+    let mut best: Option<&str> = None;
+    let mut best_streams = 0usize;
+    let mut from = 0;
+    while let Some((s, e)) = xml::find_element(text, "playlist", from) {
+        let element = &text[s..e];
+        from = e;
+        // `name` is read from the element; the opening tag's `name="feature"`
+        // is the first `name=` in document order, ahead of any nested child
+        // (nested `<audio>`/`<subtitle>` carry no `name`).
+        let is_feature =
+            xml::attr(element, "name").is_some_and(|n| n.eq_ignore_ascii_case("feature"));
+        if !is_feature {
+            continue;
+        }
+        let streams = count_elements(element, "audio") + count_elements(element, "subtitle");
+        // First feature wins the tie (matches the registry's first-wins rule);
+        // a strictly richer table displaces it. `best.is_none()` so a feature
+        // with zero nested streams is still selected — its id feeds the hint.
+        if best.is_none() || streams > best_streams {
+            best_streams = streams;
+            best = Some(element);
+        }
+    }
+    best
+}
+
+/// The authoring id (digits only, e.g. "00800") of the selected feature
+/// playlist, or `None` when no feature playlist / no id is present.
+fn feature_playlist_id(text: &str) -> Option<String> {
+    let feature = select_feature_playlist(text)?;
+    let id = xml::attr(feature, "id")?;
+    let digits: String = id.chars().filter(|c| c.is_ascii_digit()).collect();
+    if digits.is_empty() {
+        return None;
+    }
+    Some(digits)
+}
+
+/// Count `<tag>` elements inside `element`.
+fn count_elements(element: &str, tag: &str) -> usize {
+    let mut n = 0;
+    let mut from = 0;
+    while let Some((_, e)) = xml::find_element(element, tag, from) {
+        n += 1;
+        from = e;
+    }
+    n
+}
+
+/// Parse a nested stream `id` (e.g. "01", "11") into its 1-based STN slot.
+/// Digits only, so a stray quote/space cannot poison it; `None` (skip the
+/// stream) when it names no slot — 0 is the module's `NO_STN_SLOT` sentinel and
+/// cannot be bound by the ordinal path.
+fn stream_number_from_id(id: &Option<String>) -> Option<u16> {
+    let id = id.as_deref()?;
+    let digits: String = id.chars().filter(|c| c.is_ascii_digit()).collect();
+    digits.parse::<u16>().ok().filter(|&n| n != 0)
+}
+
+/// Map an `<audio type>` value to a [`LabelPurpose`]. `rnib` is described-video
+/// (descriptive/narration); a `comment*` value is commentary; everything else
+/// (`feature`, unknown) is a normal program track.
+fn audio_purpose(ty: &str) -> LabelPurpose {
+    if ty == "rnib" {
+        LabelPurpose::Descriptive
+    } else if ty.contains("comment") {
+        LabelPurpose::Commentary
+    } else {
+        LabelPurpose::Normal
+    }
+}
+
+/// Map a `<subtitle>`'s `form`/`type` to a [`LabelQualifier`]. `form="sdh"`
+/// takes precedence (an SDH track is the editorially meaningful flag);
+/// otherwise `type="embed"` is a dedicated forced/embedded track. `feature`
+/// and `text` full tracks carry no qualifier.
+fn subtitle_qualifier(ty: &str, form: &str) -> LabelQualifier {
+    if form == "sdh" {
+        LabelQualifier::Sdh
+    } else if ty == "embed" {
+        LabelQualifier::Forced
+    } else {
+        LabelQualifier::None
+    }
+}
+
+/// Trim + lowercase the raw ISO 639-2 code (`"eng"`, `"fra"`, ...).
+fn normalize_language(raw: &str) -> String {
+    raw.trim().to_ascii_lowercase()
+}
+
+// ── Phase 2 (design only, not implemented here) ─────────────────────────────
+//
+// Newer Fox discs (Deadpool, etc., surveyed as 11 discs currently mis-owned by
+// the deluxe stub) ship NO loose `dcx.xml`. They wrap the same per-stream data
+// inside `com/foxbd` BD-J `.class` bytecode. The follow-on parser would reuse
+// `super::class_reader` the way `dbp`/`deluxe` already do:
+//
+//   * `detect` already recognises the `com/foxbd/` central-directory prefix
+//     (above), so Phase 2 only adds a parse path.
+//   * Iterate the jar's classes via `super::jar::for_each_class` and read the
+//     constant pool (`ClassFile`), which holds the authored strings verbatim:
+//       - `FeatureIntroPlaylist.play: PLAYLIST ID:` → the feature playlist id
+//         (→ the same `FeaturePlaylistHint` the dcx path should wire up),
+//       - `RNIB` → a descriptive/narration audio track (→ Descriptive),
+//       - `primaryAudioId=` and the parallel subtitle-id constants → the STN
+//         slot numbering, mirroring the `id="NN"` mapping here.
+//   * Emit the identical `StreamLabel` shape at High confidence so the two Fox
+//     forms are indistinguishable downstream.
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// The real Life of Pi manifest, reduced only by truncating the giant
+    /// chapter-mark `<properties>` blocks (which carry no stream labels). Every
+    /// `<audio>`/`<subtitle>` element and both regional feature playlists are
+    /// verbatim from `/BDMV/JAR/05001/dcx.xml`, so this fixture exercises the
+    /// exact bytes production sees: feature selection across two `name="feature"`
+    /// playlists, the nested-scope rule, and the rnib/sdh/embed flags.
+    const LIFE_OF_PI_DCX: &str = r#"<dcx>
+	<disc>
+		<properties region="ABC" regioncheckon="false" parentallevel="PG" hdronlydisc="true" bootstrap.bdjo="88888"
+		            vstaskenabled="false" defaultversion="1" topmenushowmarkid="0" topmenuloopmarkid="0"/>
+
+		<playlist id="00001" lang="eng" name="topmenu"/>
+		<playlist id="00100" lang="eng" name="foxlogo"/>
+		<playlist id="00300" lang="eng" name="copyright"/> <!-- English -->
+		<playlist id="00600" name="black" lang="eng"/>
+
+		<playlist id="00800" lang="eng" name="feature" vers="1" durs="7628">
+			<audio id="01" lang="eng" type="feature"/>
+			<audio id="02" lang="eng" type="rnib"/>
+			<audio id="03" lang="spa" dial="lat" type="feature"/>
+			<audio id="04" lang="fra" dial="par" type="feature"/>
+			<audio id="05" lang="dan" type="feature"/>
+			<audio id="06" lang="nld" type="feature"/>
+			<audio id="07" lang="fin" type="feature"/>
+			<audio id="08" lang="deu" type="feature"/>
+			<audio id="09" lang="ita" type="feature"/>
+			<audio id="10" lang="nor" type="feature"/>
+			<audio id="11" lang="swe" type="feature"/>
+			<subtitle id="01" lang="eng" type="feature" form="sdh"/>
+			<subtitle id="02" lang="spa" dial="lat" type="embed"/>
+			<subtitle id="03" lang="fra" dial="par" type="embed"/>
+			<subtitle id="04" lang="dan" type="embed"/>
+			<subtitle id="05" lang="nld" type="embed"/>
+			<subtitle id="06" lang="fin" type="feature"/>
+			<subtitle id="07" lang="deu" type="embed"/>
+			<subtitle id="08" lang="ita" type="embed"/>
+			<subtitle id="09" lang="nor" type="embed"/>
+			<subtitle id="10" lang="swe" type="embed"/>
+			<subtitle id="11" lang="eng" type="text"/>
+			<properties>
+				<entry.marks ids="0,2,4,6,8,10"/>
+				<playlist.marks timecodes="00:00:00:00,00:03:58:18"/>
+			</properties>
+		</playlist>
+
+		<playlist id="00801" lang="jpn" name="feature" vers="1" durs="7628">
+			<audio id="01" lang="eng" type="feature"/>
+			<audio id="02" lang="jpn" type="feature"/>
+			<subtitle id="01" lang="jpn" type="feature"/>
+			<subtitle id="02" lang="eng" type="feature" form="sdh"/>
+			<subtitle id="03" lang="jpn" type="text"/>
+			<subtitle id="04" lang="eng" type="text"/>
+			<properties>
+				<entry.marks ids="0,2,4"/>
+			</properties>
+		</playlist>
+	</disc>
+</dcx>"#;
+
+    fn audio(labels: &[StreamLabel]) -> Vec<&StreamLabel> {
+        labels
+            .iter()
+            .filter(|l| l.stream_type == StreamLabelType::Audio)
+            .collect()
+    }
+
+    fn subs(labels: &[StreamLabel]) -> Vec<&StreamLabel> {
+        labels
+            .iter()
+            .filter(|l| l.stream_type == StreamLabelType::Subtitle)
+            .collect()
+    }
+
+    /// The primary feature is the richer `00800` (eng) table, not `00801`
+    /// (jpn). Both are `name="feature"`; selection must pick by stream count,
+    /// and the id we surface for the (future) FeaturePlaylistHint is `00800`.
+    #[test]
+    fn selects_richest_feature_playlist_and_its_id() {
+        assert_eq!(
+            feature_playlist_id(LIFE_OF_PI_DCX),
+            Some("00800".to_string())
+        );
+    }
+
+    /// Full real-disc parse: the 00800 audio table. Eleven tracks, id order =
+    /// STN slot, and slot 2 (`eng rnib`) is the descriptive/narration track.
+    #[test]
+    fn life_of_pi_audio_labels() {
+        let labels = labels_from_dcx(LIFE_OF_PI_DCX);
+        let a = audio(&labels);
+        assert_eq!(
+            a.len(),
+            11,
+            "00800 has eleven audio tracks, 00801 not merged"
+        );
+
+        // Slots and languages, in id order.
+        let got: Vec<(u16, &str, LabelPurpose)> = a
+            .iter()
+            .map(|l| (l.stream_number, l.language.as_str(), l.purpose))
+            .collect();
+        assert_eq!(
+            got,
+            vec![
+                (1, "eng", LabelPurpose::Normal),
+                (2, "eng", LabelPurpose::Descriptive), // rnib = described video
+                (3, "spa", LabelPurpose::Normal),
+                (4, "fra", LabelPurpose::Normal),
+                (5, "dan", LabelPurpose::Normal),
+                (6, "nld", LabelPurpose::Normal),
+                (7, "fin", LabelPurpose::Normal),
+                (8, "deu", LabelPurpose::Normal),
+                (9, "ita", LabelPurpose::Normal),
+                (10, "nor", LabelPurpose::Normal),
+                (11, "swe", LabelPurpose::Normal),
+            ]
+        );
+        // Vendor labels: no StreamId, they bind by ordinal STN slot.
+        assert!(a.iter().all(|l| l.stream_id.is_none()));
+    }
+
+    /// Full real-disc parse: the 00800 subtitle table. `form="sdh"` → Sdh,
+    /// `type="embed"` → Forced, `feature`/`text` → no qualifier.
+    #[test]
+    fn life_of_pi_subtitle_labels() {
+        let labels = labels_from_dcx(LIFE_OF_PI_DCX);
+        let s = subs(&labels);
+        assert_eq!(s.len(), 11, "00800 has eleven subtitle tracks");
+
+        let got: Vec<(u16, &str, LabelQualifier)> = s
+            .iter()
+            .map(|l| (l.stream_number, l.language.as_str(), l.qualifier))
+            .collect();
+        assert_eq!(
+            got,
+            vec![
+                (1, "eng", LabelQualifier::Sdh),    // feature + form=sdh
+                (2, "spa", LabelQualifier::Forced), // embed
+                (3, "fra", LabelQualifier::Forced),
+                (4, "dan", LabelQualifier::Forced),
+                (5, "nld", LabelQualifier::Forced),
+                (6, "fin", LabelQualifier::None), // feature
+                (7, "deu", LabelQualifier::Forced),
+                (8, "ita", LabelQualifier::Forced),
+                (9, "nor", LabelQualifier::Forced),
+                (10, "swe", LabelQualifier::Forced),
+                (11, "eng", LabelQualifier::None), // text
+            ]
+        );
+    }
+
+    /// The nested-scope rule: audio/subtitle come from ONE feature playlist,
+    /// never a document-wide scan that would merge 00800 and 00801 and collide
+    /// their `id="01"` slots. If scoping regressed, slot 1 audio would appear
+    /// twice and the count would jump past 11.
+    #[test]
+    fn does_not_merge_regional_feature_playlists() {
+        let labels = labels_from_dcx(LIFE_OF_PI_DCX);
+        let a = audio(&labels);
+        // Exactly one audio label per STN slot 1..=11.
+        let slot1: Vec<_> = a.iter().filter(|l| l.stream_number == 1).collect();
+        assert_eq!(slot1.len(), 1, "one stream on slot 1, not one per playlist");
+        assert_eq!(audio(&labels).len() + subs(&labels).len(), 22);
+    }
+
+    /// The `rnib` described-video mapping in isolation, plus the commentary
+    /// path (no real Life of Pi track uses it, so it is pinned synthetically).
+    #[test]
+    fn audio_purpose_mapping() {
+        assert_eq!(audio_purpose("feature"), LabelPurpose::Normal);
+        assert_eq!(audio_purpose("rnib"), LabelPurpose::Descriptive);
+        assert_eq!(audio_purpose("commentary"), LabelPurpose::Commentary);
+        assert_eq!(
+            audio_purpose("director-commentary"),
+            LabelPurpose::Commentary
+        );
+        assert_eq!(audio_purpose("unknown"), LabelPurpose::Normal);
+    }
+
+    /// `form="sdh"` outranks `type`; `embed` is forced; full tracks are None.
+    #[test]
+    fn subtitle_qualifier_mapping() {
+        assert_eq!(subtitle_qualifier("feature", "sdh"), LabelQualifier::Sdh);
+        assert_eq!(subtitle_qualifier("embed", ""), LabelQualifier::Forced);
+        assert_eq!(subtitle_qualifier("feature", ""), LabelQualifier::None);
+        assert_eq!(subtitle_qualifier("text", ""), LabelQualifier::None);
+        // An SDH embedded track (hypothetical) still flags SDH, the richer fact.
+        assert_eq!(subtitle_qualifier("embed", "sdh"), LabelQualifier::Sdh);
+    }
+
+    /// `id="NN"` becomes the 1-based STN slot; a missing/zero id names no slot.
+    #[test]
+    fn stream_number_from_id_digits_only() {
+        assert_eq!(stream_number_from_id(&Some("01".into())), Some(1));
+        assert_eq!(stream_number_from_id(&Some("11".into())), Some(11));
+        assert_eq!(stream_number_from_id(&Some(" 07 ".into())), Some(7));
+        assert_eq!(stream_number_from_id(&Some("00".into())), None);
+        assert_eq!(stream_number_from_id(&None), None);
+        assert_eq!(stream_number_from_id(&Some("".into())), None);
+    }
+
+    // ── Negative detection ─────────────────────────────────────────────────
+
+    /// A document that is not a Fox feature manifest yields no labels. Three
+    /// shapes: empty, a `<dcx>` whose playlists are all non-feature menu/logo
+    /// clips (no `name="feature"`), and unrelated XML. None must be mistaken
+    /// for a Fox feature table.
+    #[test]
+    fn non_feature_manifest_yields_no_labels() {
+        assert!(labels_from_dcx("").is_empty());
+        assert!(labels_from_dcx("<not-dcx><playlist name=\"x\"/></not-dcx>").is_empty());
+        let menus_only = r#"<dcx><disc>
+            <playlist id="00001" lang="eng" name="topmenu"/>
+            <playlist id="00100" lang="eng" name="foxlogo"/>
+            <playlist id="00600" name="black" lang="eng"/>
+        </disc></dcx>"#;
+        assert!(
+            labels_from_dcx(menus_only).is_empty(),
+            "no <playlist name=\"feature\"> → nothing to label"
+        );
+        assert_eq!(feature_playlist_id(menus_only), None);
+    }
+
+    /// A feature playlist with no nested streams (an authoring edge) produces
+    /// no labels rather than a spurious empty-slot entry.
+    #[test]
+    fn feature_without_streams_yields_no_labels() {
+        let doc = r#"<dcx><disc>
+            <playlist id="00800" lang="eng" name="feature" durs="7628"/>
+        </disc></dcx>"#;
+        assert!(labels_from_dcx(doc).is_empty());
+        // ...but the id is still recoverable for the feature hint.
+        assert_eq!(feature_playlist_id(doc), Some("00800".to_string()));
+    }
+}
diff --git a/src/labels/mod.rs b/src/labels/mod.rs
index b4d93ca7..8be9e61e 100644
--- a/src/labels/mod.rs
+++ b/src/labels/mod.rs
@@ -16,6 +16,7 @@ mod criterion;
 mod ctrm;
 mod dbp;
 mod deluxe;
+mod fox;
 pub(crate) mod jar;
 mod mpls_universal;
 mod paramount;
@@ -201,6 +202,13 @@ const PARSERS: &[(&str, DetectFn, ParseFn)] = &[
     // walking).
     ("dbp", dbp::detect, dbp::parse),
     ("deluxe", deluxe::detect, deluxe::parse),
+    // Fox — older discs ship a loose plain-XML `/BDMV/JAR/<id>/dcx.xml`
+    // manifest (root `<dcx>`) with per-stream language/purpose/qualifier.
+    // High confidence: fully structured, no guessing. Registered ahead of
+    // the universal MPLS fallback so its editorial labels win. Newer Fox
+    // wraps the same data in `com/foxbd` bytecode (see fox.rs Phase 2 note),
+    // which this parser detects but does not yet decode.
+    ("fox", fox::detect, fox::parse),
     // Universal MPLS fallback. Returns Confidence::Low so framework
     // parsers always win when they match. Closes the "no framework
     // matched" gap (e.g. HDMV-only discs) with spec-derived language
@@ -1526,15 +1534,16 @@ mod registry_tests {
                 "ctrm",
                 "dbp",
                 "deluxe",
+                "fox",
                 "mpls_universal",
                 "png_filenames",
             ],
             "PARSERS array order changed — file-presence/reader-gated High \
              parsers (paramount/criterion/pixelogic/ctrm) stay first; dbp + \
-             deluxe (now real com/<vendor>/ prefix detect) stay before \
-             mpls_universal; mpls_universal stays the universal Low fallback; \
-             png_filenames (Low, language-only hint) stays LAST so MPLS wins \
-             the Low tie whenever it produces anything."
+             deluxe (now real com/<vendor>/ prefix detect) and fox (dcx.xml / \
+             com/foxbd) stay before mpls_universal; mpls_universal stays the \
+             universal Low fallback; png_filenames (Low, language-only hint) \
+             stays LAST so MPLS wins the Low tie whenever it produces anything."
         );
     }