feat(dates): container video dates, filesystem branch, manual edit (#115)

The exiftool branch of the date waterfall now pulls raw strings with
group prefixes (one `exiftool -j -q -G1` subprocess per batch, no
`-d %s`) and classifies each candidate:

- zoned strings (own offset / Z) are true instants;
- naive strings from container groups (QuickTime/Track*/Apple) are
  UTC-rendered creation_time fields -> true instants (utc_direct).
  Running them through the camera wall-clock cascade was the
  "videos off by 4-5 hours" bug: it reinterpreted a UTC instant in
  the server zone;
- naive strings from photo-EXIF groups are camera wall clocks and run
  the offset cascade (OffsetTime* pairing + GPS evidence pulled in
  the same exiftool pass).

The legacy date_taken column stays byte-identical to the old
server-local interpretation (reproduced in Rust, DST-aware); the
new-contract date_utc / camera_offset_minutes / date_taken_tz_source
columns carry the true instant.

Manual date edit (POST /image/exif/date) reinterprets the
naive-as-UTC epoch the client sent as a wall clock in the user's
display zone (camera_tz::manual_date_resolution, tz_source =
'manual'), snapshots the pre-override new-contract triple next to the
existing legacy snapshot pair (3 new columns, migration
2026-09-25-000000), and revert restores both pairs.

ADR-0001 records the container-date finding; CLAUDE.md date-pipeline
section updated.

CLAUDE.md

@@ -380,9 +380,21 @@ land on this date?". Order:
    QuickTime/MP4 (`MediaCreateDate`, `TrackCreateDate`, `CreateDate`),
    Apple's `ContentCreateDate`, MakerNote sub-IFDs. Required for
    videos to land a real date. Single-file at ingest; the per-tick
-   drain feeds the whole batch through one `exiftool -@ -` subprocess.
-   Degrades silently when `exiftool` isn't on PATH (resolver caches the
-   "available" check via `OnceLock`).
+   drain feeds the whole batch through one `exiftool -j -q -G1 -@ -`
+   subprocess (raw strings + group prefixes, parsed in Rust — no
+   `-d %s`). Degrades silently when `exiftool` isn't on PATH (resolver
+   caches the "available" check via `OnceLock`).
+   **Group classification (ADR-0001, ticket #115):** zoned strings
+   (own offset / `Z`) are true instants; naive strings from container
+   groups (QuickTime/Track*/Apple) are UTC-rendered `creation_time`
+   fields → true instants (`utc_direct`, no cascade — running them
+   through the wall-clock cascade was the "videos off by 4–5 hours"
+   bug); naive strings from photo-EXIF groups are camera wall clocks →
+   offset cascade (`OffsetTime*` + GPS evidence pulled in the same
+   pass). The legacy `date_taken` column stays byte-identical to the
+   old server-local `-d %s` interpretation; the new-contract
+   `date_utc` / `camera_offset_minutes` / `date_taken_tz_source`
+   columns carry the true instant.
 3. **`filename`** — `extract_date_from_filename` in `memories.rs`
    matches screenshot, chat-export, and timestamp-named patterns.
 4. **`fs_time`** — `earliest_fs_time(metadata)` (earlier of created /
@@ -401,8 +413,9 @@ watcher tick alongside `backfill_unhashed_backlog` (also `src/backfill.rs`). It
 `date_taken IS NULL` (backed by the `idx_image_exif_date_backfill`
 partial index), runs the waterfall batch via `resolve_dates_batch`,
 and writes results via the `backfill_date_taken` DAO method (touches
-only `date_taken` + `date_taken_source` so EXIF / hash / perceptual
-columns are preserved). Resolved rows — including the ones the
+`date_taken` + `date_taken_source` plus the new-contract
+`date_utc` / `camera_offset_minutes` / `date_taken_tz_source` triple,
+so EXIF / hash / perceptual columns are preserved). Resolved rows — including the ones the
 waterfall could only resolve via `fs_time` — are not re-eligible:
 the resolver is deterministic on file bytes + filename + fs metadata,
 so re-running on the same inputs lands on the same source every time.

docs/adr/0001-true-utc-dates.md

@@ -22,7 +22,11 @@ actual moment). The wall clock the camera showed is a **display value**, recover
 instant plus a per-row **camera offset** resolved at ingest by a cascade (explicit EXIF
 offset tag → GPS position → server zone, the last recorded as an assumption). Day-level
 grouping uses the owner's **display zone** (an IANA zone name). Manual edits enter as wall
-clocks in the display zone and are stored as instants.
+clocks in the display zone (rendered naive-as-UTC by the client) and are
+stored as instants; the legacy column keeps the sent value verbatim and
+revert restores a snapshot of both the legacy pair and the new-contract
+triple (`original_date_taken*` / `original_date_utc` /
+`original_camera_offset_minutes` / `original_date_taken_tz_source`).
 
 Consequences of the decision:
 
@@ -59,3 +63,20 @@ Consequences of the decision:
 - **Re-dating across a day boundary invalidates derived day data** (daily summaries, reel
   pre-gen), which regenerates on its normal schedule; the backfill drain detects the day
   change per row.
+- **Container dates are true instants, not wall clocks.** QuickTime/MP4/MOV
+  `creation_time` fields are seconds-since-1904 in UTC; exiftool renders them as
+  UTC-naive strings. Running a naive container string through the camera wall-clock
+  cascade reinterprets a UTC instant in the server zone and shifts every video by the
+  server's UTC offset (the "videos off by 4–5 hours" bug, ticket #115). Verified against
+  production data: a mirrorless video lands inside the same-moment photo burst, and the
+  delta across all sampled videos is the uniform server EDT/EST offset. So the exiftool
+  branch classifies the *group* of each tag: zoned strings are instants outright,
+  container-group naives are instants (`utc_direct`), and only photo-EXIF-group naives
+  run the cascade. The legacy column for those rows stays byte-identical to the old
+  `-d %s` server-local interpretation; the new-contract columns carry the true instant.
+- **The legacy column is reproduced in Rust, not by re-invoking exiftool.** The old
+  `-d %s` path interpreted exiftool's rendered naive string in the *server's* local zone
+  (DST-aware, ignoring the file's own `OffsetTime*` tags — verified). `date_taken`
+  for exiftool rows must keep producing exactly that value, so the resolver parses the
+  raw string and applies the server-zone interpretation itself (`utc_direct` rows skip
+  the cascade but still get the server-local legacy value).

migrations/2026-09-25-000000_manual_date_triple_snapshot/down.sql

@@ -0,0 +1,3 @@
+ALTER TABLE image_exif DROP COLUMN original_date_utc;
+ALTER TABLE image_exif DROP COLUMN original_camera_offset_minutes;
+ALTER TABLE image_exif DROP COLUMN original_date_taken_tz_source;

migrations/2026-09-25-000000_manual_date_triple_snapshot/up.sql

@@ -0,0 +1,13 @@
+-- Manual date-edit rework (ticket #115).
+--
+-- POST /image/exif/date now writes the new-contract triple
+-- (date_utc, camera_offset_minutes, date_taken_tz_source = 'manual')
+-- alongside the legacy (date_taken, date_taken_source) pair. Reverting an
+-- override must restore the resolver's new-contract triple as well as the
+-- legacy pair, so image_exif snapshots the pre-override new-contract
+-- columns next to the existing legacy snapshot pair
+-- (original_date_taken / original_date_taken_source).
+
+ALTER TABLE image_exif ADD COLUMN original_date_utc BIGINT;
+ALTER TABLE image_exif ADD COLUMN original_camera_offset_minutes INTEGER;
+ALTER TABLE image_exif ADD COLUMN original_date_taken_tz_source TEXT;

src/ai/insight_chat.rs

@@ -3381,6 +3381,9 @@ mod tests {
             date_utc: Some(1_629_028_800),
             camera_offset_minutes: None,
             date_taken_tz_source: Some("utc_direct".to_string()),
+            original_date_utc: None,
+            original_camera_offset_minutes: None,
+            original_date_taken_tz_source: None,
         });
         let out = resolve_date_taken_for_context(&exif, "Screenshot_2014-06-01.png");
         assert_eq!(out.as_deref(), Some("2021-08-15"));

src/camera_tz.rs

@@ -40,9 +40,8 @@ pub enum TzSource {
     /// The resolver branch already produced a true UTC instant (exiftool,
     /// filesystem time, unix-timestamp filename). No offset is involved.
     UtcDirect,
-    /// An operator set the date manually.
-    // Written by the manual-edit rework (#118); nothing constructs it yet.
-    #[allow(dead_code)]
+    /// An operator set the date manually (POST /image/exif/date, ticket
+    /// #115): the wall the user picked, interpreted in their display zone.
     Manual,
 }
 
@@ -218,13 +217,39 @@ pub const DEFAULT_DISPLAY_TZ: &str = "America/New_York";
 /// NULL / empty / unparseable prefs fall back to the app default, so
 /// read paths (tickets #119/#120) never have to special-case the
 /// unset state themselves.
-pub fn display_zone_for(stored: Option<&str>) -> &str {
+pub fn display_zone_for(stored: Option<&str>) -> String {
     match stored.map(str::trim).filter(|s| !s.is_empty()) {
-        Some(name) if Tz::from_str(name).is_ok() => name,
-        _ => DEFAULT_DISPLAY_TZ,
+        Some(name) if Tz::from_str(name).is_ok() => name.to_string(),
+        _ => DEFAULT_DISPLAY_TZ.to_string(),
     }
 }
 
+/// Pure seam for the manual date-edit endpoints (ADR-0001, ticket #115):
+/// reinterpret the naive-as-UTC epoch the UI sent as a wall clock in the
+/// user's display zone, and produce the new-contract
+/// `(date_utc, camera_offset_minutes)` pair. The caller writes
+/// `date_taken_tz_source = 'manual'` itself and stores the epoch verbatim
+/// in the legacy `date_taken` column (byte-identical to the pre-rework
+/// behavior).
+///
+/// `stored_zone` is `user_ai_prefs.display_tz` (NULL / unparseable → app
+/// default). The offset follows the wall's own date through the zone's DST
+/// rules — ambiguous fall-back walls take the earlier (pre-transition)
+/// offset; nonexistent spring-forward walls take the zone's offset at the
+/// wall-as-UTC reading, within an hour of truth (see
+/// [`offset_minutes_for_zone`]). `None` only when the zone name is
+/// unparseable, which [`display_zone_for`] already rules out — the caller
+/// then leaves the new-contract triple untouched.
+pub fn manual_date_resolution(
+    stored_zone: Option<&str>,
+    wall_naive_epoch: i64,
+) -> Option<(i64, i32)> {
+    let zone = Tz::from_str(&display_zone_for(stored_zone)).ok()?;
+    let wall = chrono::DateTime::from_timestamp(wall_naive_epoch, 0).map(|dt| dt.naive_utc())?;
+    let minutes = offset_minutes_for_zone(zone, wall);
+    Some((wall_to_instant(wall, minutes), minutes))
+}
+
 /// Display-zone offset, in minutes, for a true UTC instant — DST-aware.
 /// `None` when the zone name doesn't parse.
 #[allow(dead_code)] // consumed by the read-side cutover (#119/#120)
@@ -240,10 +265,13 @@ mod tests {
 
     #[test]
     fn display_zone_for_falls_back_to_default() {
-        assert_eq!(display_zone_for(None), DEFAULT_DISPLAY_TZ);
-        assert_eq!(display_zone_for(Some("")), DEFAULT_DISPLAY_TZ);
-        assert_eq!(display_zone_for(Some("  ")), DEFAULT_DISPLAY_TZ);
-        assert_eq!(display_zone_for(Some("Not/A_Zone")), DEFAULT_DISPLAY_TZ);
+        assert_eq!(display_zone_for(None).as_str(), DEFAULT_DISPLAY_TZ);
+        assert_eq!(display_zone_for(Some("")).as_str(), DEFAULT_DISPLAY_TZ);
+        assert_eq!(display_zone_for(Some("  ")).as_str(), DEFAULT_DISPLAY_TZ);
+        assert_eq!(
+            display_zone_for(Some("Not/A_Zone")).as_str(),
+            DEFAULT_DISPLAY_TZ
+        );
     }
 
     #[test]
@@ -359,6 +387,39 @@ mod tests {
         );
     }
 
+    #[test]
+    fn manual_date_resolution_display_zone_edt() {
+        // The UI sends the wall rendered in the display zone, as a
+        // naive-as-UTC epoch: 1720080000 = "2024-07-04 04:00:00". July in
+        // New York is EDT (-240): the instant is 08:00:00Z.
+        let (utc, off) = manual_date_resolution(Some("America/New_York"), 1_720_080_000).unwrap();
+        assert_eq!(off, -240);
+        assert_eq!(utc, 1_720_080_000 + 4 * 3600);
+    }
+
+    #[test]
+    fn manual_date_resolution_display_zone_est() {
+        // Same function in January: EST (-300). Wall 2024-01-15 04:00:00
+        // (naive epoch 1705291200) → 09:00:00Z.
+        let (utc, off) = manual_date_resolution(Some("America/New_York"), 1_705_291_200).unwrap();
+        assert_eq!(off, -300);
+        assert_eq!(utc, 1_705_291_200 + 5 * 3600);
+    }
+
+    #[test]
+    fn manual_date_resolution_positive_zone_and_default() {
+        // Tokyo is +09:00 year-round: wall 04:00 → previous day 19:00Z.
+        let (utc, off) = manual_date_resolution(Some("Asia/Tokyo"), 1_720_080_000).unwrap();
+        assert_eq!(off, 540);
+        assert_eq!(utc, 1_720_080_000 - 540 * 60);
+        // NULL stored zone → app default (America/New_York), July → EDT.
+        let (_, off) = manual_date_resolution(None, 1_720_080_000).unwrap();
+        assert_eq!(off, -240);
+        // Unparseable stored zone also falls back to the default.
+        let (_, off) = manual_date_resolution(Some("Not/A_Zone"), 1_720_080_000).unwrap();
+        assert_eq!(off, -240);
+    }
+
     #[test]
     fn display_zone_offset_minutes_unknown_zone_is_none() {
         assert_eq!(

src/data/mod.rs

@@ -307,6 +307,14 @@ pub struct ExifMetadata {
     pub original_date_taken: Option<i64>,
     /// When `date_taken_source = "manual"`, the prior source.
     pub original_date_taken_source: Option<String>,
+    /// When `date_taken_source = "manual"`, the prior `date_utc` snapshot
+    /// (the new-contract triple the revert restores alongside the legacy
+    /// pair above).
+    pub original_date_utc: Option<i64>,
+    /// When `date_taken_source = "manual"`, the prior camera offset.
+    pub original_camera_offset_minutes: Option<i32>,
+    /// When `date_taken_source = "manual"`, the prior tz source.
+    pub original_date_taken_tz_source: Option<String>,
 }
 
 #[derive(Debug, Serialize)]
@@ -397,6 +405,9 @@ impl From<ImageExif> for ExifMetadata {
             date_taken_tz_source: exif.date_taken_tz_source,
             original_date_taken: exif.original_date_taken,
             original_date_taken_source: exif.original_date_taken_source,
+            original_date_utc: exif.original_date_utc,
+            original_camera_offset_minutes: exif.original_camera_offset_minutes,
+            original_date_taken_tz_source: exif.original_date_taken_tz_source,
         }
     }
 }
@@ -624,6 +635,9 @@ mod date_contract_tests {
             date_utc: Some(1_720_108_800),
             camera_offset_minutes: Some(-240),
             date_taken_tz_source: Some("offset_tag".to_string()),
+            original_date_utc: None,
+            original_camera_offset_minutes: None,
+            original_date_taken_tz_source: None,
         }
     }
 

src/database/mod.rs

@@ -568,25 +568,32 @@ pub trait ExifDao: Sync + Send {
         model_version: Option<&str>,
     ) -> Result<Vec<(String, Vec<u8>)>, DbError>;
 
-    /// Operator-driven date_taken override (POST /image/exif/date). Snapshots
-    /// the prior `(date_taken, date_taken_source)` into the `original_*`
-    /// pair on first override, then writes the new value with
-    /// `date_taken_source = 'manual'`. Subsequent overrides keep the
-    /// original snapshot intact so a single revert restores the resolver
-    /// result, not whatever override was set just before. Returns the
-    /// post-update row.
+    /// Operator-driven date_taken override (POST /image/exif/date).
+    /// `date_taken` is the naive-as-UTC epoch the UI sent; the legacy
+    /// column stores it verbatim (byte-identical to the pre-rework
+    /// behavior). The new-contract triple (ADR-0001, ticket #115) is
+    /// computed from the same value as a wall clock in `display_tz` —
+    /// the user's display zone — with `date_taken_source = 'manual'`.
+    /// Snapshots the prior legacy pair AND prior new-contract triple into
+    /// the `original_*` columns on first override; subsequent overrides
+    /// keep the original snapshot intact so a single revert restores the
+    /// resolver result, not whatever override was set just before.
+    /// Returns the post-update row.
     fn set_manual_date_taken(
         &mut self,
         context: &opentelemetry::Context,
         library_id: i32,
         rel_path: &str,
         date_taken: i64,
+        display_tz: &str,
     ) -> Result<ImageExif, DbError>;
 
     /// Revert a manual override (POST /image/exif/date/clear): restore
-    /// `date_taken` + `date_taken_source` from the `original_*` snapshot,
-    /// then null both originals. No-op (returns current row unchanged) when
-    /// no override is active.
+    /// `date_taken` + `date_taken_source` AND the new-contract triple
+    /// (`date_utc` / `camera_offset_minutes` / `date_taken_tz_source`,
+    /// ADR-0001 ticket #115) from the `original_*` snapshots, then null
+    /// all five. No-op (returns current row unchanged) when no override is
+    /// active.
     fn clear_manual_date_taken(
         &mut self,
         context: &opentelemetry::Context,
@@ -1640,6 +1647,7 @@ impl ExifDao for SqliteExifDao {
         library_id_val: i32,
         rel_path_val: &str,
         date_taken_val: i64,
+        display_tz_val: &str,
     ) -> Result<ImageExif, DbError> {
         trace_db_call(context, "update", "set_manual_date_taken", |_span| {
             use schema::image_exif::dsl::*;
@@ -1652,16 +1660,49 @@ impl ExifDao for SqliteExifDao {
             let current =
                 locate_image_exif_row(connection.deref_mut(), library_id_val, rel_path_val)?;
 
-            // Snapshot only on first override. Subsequent overrides keep
-            // the original snapshot intact so a single revert restores
-            // the resolver-derived value, not the prior override.
-            let (orig_dt, orig_src) = if current.original_date_taken.is_none() {
-                (current.date_taken, current.date_taken_source.clone())
-            } else {
-                (
-                    current.original_date_taken,
-                    current.original_date_taken_source.clone(),
-                )
+            // Snapshot both pairs only on first override. Subsequent
+            // overrides keep the original snapshot intact so a single
+            // revert restores the resolver-derived value, not the prior
+            // override.
+            let (orig_dt, orig_src, orig_dt_utc, orig_offset, orig_tz) =
+                if current.original_date_taken.is_none() {
+                    (
+                        current.date_taken,
+                        current.date_taken_source.clone(),
+                        current.date_utc,
+                        current.camera_offset_minutes,
+                        current.date_taken_tz_source.clone(),
+                    )
+                } else {
+                    (
+                        current.original_date_taken,
+                        current.original_date_taken_source.clone(),
+                        current.original_date_utc,
+                        current.original_camera_offset_minutes,
+                        current.original_date_taken_tz_source.clone(),
+                    )
+                };
+
+            // The user's wall clock reinterpreted in their display zone
+            // (ADR-0001, ticket #115). `manual_date_resolution` is the
+            // pure seam; `None` (unreachable in practice —
+            // `display_zone_for` always yields a parseable zone) keeps
+            // the resolver's existing triple while the legacy columns
+            // still update.
+            let (new_utc, new_offset, new_tz) = match crate::camera_tz::manual_date_resolution(
+                Some(display_tz_val),
+                date_taken_val,
+            ) {
+                Some((utc, offset)) => (
+                    Some(utc),
+                    Some(offset),
+                    Some(crate::camera_tz::TzSource::Manual.as_str().to_string()),
+                ),
+                None => (
+                    current.date_utc,
+                    current.camera_offset_minutes,
+                    current.date_taken_tz_source.clone(),
+                ),
             };
 
             // Update by primary key so we hit the exact row we read,
@@ -1673,6 +1714,12 @@ impl ExifDao for SqliteExifDao {
                     date_taken_source.eq(Some("manual".to_string())),
                     original_date_taken.eq(orig_dt),
                     original_date_taken_source.eq(orig_src),
+                    original_date_utc.eq(orig_dt_utc),
+                    original_camera_offset_minutes.eq(orig_offset),
+                    original_date_taken_tz_source.eq(orig_tz),
+                    date_utc.eq(new_utc),
+                    camera_offset_minutes.eq(new_offset),
+                    date_taken_tz_source.eq(new_tz),
                 ))
                 .execute(connection.deref_mut())
                 .map_err(|e| anyhow::Error::from(e).context("update_failed"))?;
@@ -1718,8 +1765,14 @@ impl ExifDao for SqliteExifDao {
                 .set((
                     date_taken.eq(current.original_date_taken),
                     date_taken_source.eq(current.original_date_taken_source.clone()),
+                    date_utc.eq(current.original_date_utc),
+                    camera_offset_minutes.eq(current.original_camera_offset_minutes),
+                    date_taken_tz_source.eq(current.original_date_taken_tz_source.clone()),
                     original_date_taken.eq::<Option<i64>>(None),
                     original_date_taken_source.eq::<Option<String>>(None),
+                    original_date_utc.eq::<Option<i64>>(None),
+                    original_camera_offset_minutes.eq::<Option<i32>>(None),
+                    original_date_taken_tz_source.eq::<Option<String>>(None),
                 ))
                 .execute(connection.deref_mut())
                 .map_err(|e| anyhow::Error::from(e).context("update_failed"))?;

src/database/models.rs

@@ -208,6 +208,14 @@ pub struct ImageExif {
     pub camera_offset_minutes: Option<i32>,
     /// How the offset was determined. See `camera_tz::TzSource`.
     pub date_taken_tz_source: Option<String>,
+    /// Snapshot of the prior `date_utc` taken on first manual override.
+    /// NULL when no override is active. POST /image/exif/date/clear
+    /// restores the new-contract triple from these columns.
+    pub original_date_utc: Option<i64>,
+    /// Snapshot of the prior `camera_offset_minutes` (first override).
+    pub original_camera_offset_minutes: Option<i32>,
+    /// Snapshot of the prior `date_taken_tz_source` (first override).
+    pub original_date_taken_tz_source: Option<String>,
 }
 
 #[derive(Insertable, Clone)]

src/database/schema.rs

@@ -143,6 +143,9 @@ diesel::table! {
         date_utc -> Nullable<BigInt>,
         camera_offset_minutes -> Nullable<Integer>,
         date_taken_tz_source -> Nullable<Text>,
+        original_date_utc -> Nullable<BigInt>,
+        original_camera_offset_minutes -> Nullable<Integer>,
+        original_date_taken_tz_source -> Nullable<Text>,
     }
 }
 

src/date_resolver.rs

@@ -10,7 +10,12 @@
 //!    can't: QuickTime/MP4 (`MediaCreateDate`, `TrackCreateDate`,
 //!    `CreateDate`), Apple's `ContentCreateDate`, MakerNote sub-IFDs.
 //!    Required for videos to land a real date; degrades silently when
-//!    `exiftool` isn't on PATH.
+//!    `exiftool` isn't on PATH. Unlike the kamadak branch, this branch
+//!    reads raw date *strings* (no `-d %s`) and interprets them itself:
+//!    QuickTime/MP4 container dates are true instants (UTC-rendered
+//!    `creation_time` fields) and skip the cascade; photo-EXIF wall
+//!    clocks run the cascade over the file's own `OffsetTime*` / GPS
+//!    evidence (ADR-0001, ticket #115).
 //! 3. **filename regex** — `memories::extract_date_from_filename` covers
 //!    common screenshot / chat-export / timestamp-named patterns.
 //! 4. **earliest filesystem time** — `utils::earliest_fs_time` picks the
@@ -32,9 +37,8 @@ use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
 use std::sync::OnceLock;
 
-use chrono::{DateTime, NaiveDateTime, Utc};
+use chrono::{DateTime, Datelike, Local, LocalResult, NaiveDateTime, TimeZone, Utc};
 use log::{debug, trace, warn};
-use serde::Deserialize;
 
 use crate::camera_tz;
 use crate::utils::earliest_fs_time;
@@ -148,16 +152,8 @@ pub fn resolve_date_taken(path: &Path, prior_exif: Option<&ExifPrior>) -> Option
     if let Some(prior) = prior_exif {
         return Some(exif_prior_resolved(prior));
     }
-    if let Some(ts) = exiftool_date_single(path) {
-        return Some(ResolvedDate {
-            timestamp: ts,
-            source: DateSource::Exiftool,
-            // exiftool's `-d %s` conversion interprets the container date
-            // in the server's local zone — already a true UTC instant.
-            date_utc: Some(ts),
-            camera_offset_minutes: None,
-            tz_source: Some(camera_tz::TzSource::UtcDirect),
-        });
+    if let Some(resolved) = exiftool_date_single(path) {
+        return Some(resolved);
     }
     if let Some(dt) = path
         .file_name()
@@ -214,20 +210,10 @@ pub fn resolve_dates_batch(
     }
 
     if !needs_exiftool.is_empty() {
-        let exiftool_results = exiftool_dates_batch(&needs_exiftool);
-        for path in &needs_exiftool {
-            if let Some(&ts) = exiftool_results.get(*path) {
-                out.insert(
-                    path.to_path_buf(),
-                    ResolvedDate {
-                        timestamp: ts,
-                        source: DateSource::Exiftool,
-                        date_utc: Some(ts),
-                        camera_offset_minutes: None,
-                        tz_source: Some(camera_tz::TzSource::UtcDirect),
-                    },
-                );
-            }
+        // One subprocess for the whole batch; each entry is already fully
+        // resolved (legacy + new-contract fields).
+        for (path, resolved) in exiftool_dates_batch(&needs_exiftool) {
+            out.insert(path, resolved);
         }
     }
 
@@ -272,7 +258,7 @@ pub fn resolve_dates_batch(
     out
 }
 
-/// Tag priority for exiftool extraction. First non-zero value wins.
+/// Tag priority for exiftool extraction. First parseable value wins.
 ///
 /// Photos: `DateTimeOriginal` (original capture) and `SubSecDateTimeOriginal`
 /// are most authoritative. `CreateDate` is a common alias and a sane fallback.
@@ -294,6 +280,19 @@ const EXIFTOOL_DATE_TAGS: &[&str] = &[
     "ContentCreateDate",
 ];
 
+/// Offset + GPS evidence tags requested in the same exiftool pass. They
+/// feed the camera-offset cascade for naive wall-clock readings that come
+/// from photo-EXIF groups (ADR-0001).
+const EXIFTOOL_EVIDENCE_TAGS: &[&str] = &[
+    "OffsetTime",
+    "OffsetTimeOriginal",
+    "OffsetTimeDigitized",
+    "GPS:GPSLatitude",
+    "GPS:GPSLatitudeRef",
+    "GPS:GPSLongitude",
+    "GPS:GPSLongitudeRef",
+];
+
 /// Cache the "exiftool exists on PATH" check across the process lifetime so
 /// the per-tick backfill doesn't fork a doomed subprocess every iteration on
 /// deploys without exiftool installed.
@@ -314,6 +313,20 @@ fn exiftool_available() -> bool {
     })
 }
 
+/// Append the exiftool arguments shared by the single-file and batch
+/// invocations: raw date strings (no `-d %s` — the resolver interprets
+/// them itself) with group prefixes for classification, plus the offset
+/// / GPS evidence tags for the cascade.
+fn exiftool_common_args(cmd: &mut Command) {
+    cmd.arg("-j").arg("-q").arg("-G1");
+    for tag in EXIFTOOL_DATE_TAGS {
+        cmd.arg(format!("-{}", tag));
+    }
+    for tag in EXIFTOOL_EVIDENCE_TAGS {
+        cmd.arg(format!("-{}", tag));
+    }
+}
+
 /// One-file exiftool invocation. Used by the upload + GPS-write paths,
 /// which deal with one file at a time. The batch path uses
 /// `exiftool_dates_batch` so we don't pay subprocess startup per row.
@@ -326,31 +339,30 @@ fn exiftool_available() -> bool {
 /// that actually have a real capture date. We pre-filter to files that
 /// kamadak-exif couldn't read, so the JPEG fast-path is already covered
 /// — paying full-scan cost on the residual is the right trade.
-fn exiftool_date_single(path: &Path) -> Option<i64> {
+fn exiftool_date_single(path: &Path) -> Option<ResolvedDate> {
     if !exiftool_available() {
         return None;
     }
     let mut cmd = Command::new("exiftool");
-    cmd.arg("-j").arg("-q").arg("-d").arg("%s");
-    for tag in EXIFTOOL_DATE_TAGS {
-        cmd.arg(format!("-{}", tag));
-    }
+    exiftool_common_args(&mut cmd);
     cmd.arg(path);
     let output = cmd.output().ok()?;
     if !output.status.success() {
         trace!("exiftool exited non-zero for {:?}", path);
         return None;
     }
-    parse_exiftool_json(&output.stdout)
+    parse_exiftool_payload(&output.stdout)
         .into_iter()
         .next()
-        .map(|(_, ts)| ts)
+        .and_then(|f| resolve_exiftool_payload(&f.date_tags, &f.evidence))
 }
 
 /// Drain a batch via a single exiftool subprocess. Paths are fed on stdin
 /// via `-@ -`, so the argv stays short regardless of batch size — safe for
-/// libraries with very long path components.
-fn exiftool_dates_batch(paths: &[&Path]) -> HashMap<PathBuf, i64> {
+/// libraries with very long path components. Resolution is the same pure
+/// function as the single-file path, so the drain and ingest produce
+/// identical results for the same file.
+fn exiftool_dates_batch(paths: &[&Path]) -> HashMap<PathBuf, ResolvedDate> {
     let mut out = HashMap::new();
     if paths.is_empty() || !exiftool_available() {
         return out;
@@ -360,10 +372,7 @@ fn exiftool_dates_batch(paths: &[&Path]) -> HashMap<PathBuf, i64> {
     // No `-fast2` — see exiftool_date_single for the rationale (QuickTime
     // moov-at-end files miss CreateDate / MediaCreateDate when the trailer
     // is skipped).
-    cmd.arg("-j").arg("-q").arg("-d").arg("%s");
-    for tag in EXIFTOOL_DATE_TAGS {
-        cmd.arg(format!("-{}", tag));
-    }
+    exiftool_common_args(&mut cmd);
     cmd.arg("-@").arg("-");
     cmd.stdin(Stdio::piped())
         .stdout(Stdio::piped())
@@ -403,36 +412,328 @@ fn exiftool_dates_batch(paths: &[&Path]) -> HashMap<PathBuf, i64> {
             output.status.code()
         );
     }
-    for (source, ts) in parse_exiftool_json(&output.stdout) {
-        out.insert(PathBuf::from(source), ts);
+    for file in parse_exiftool_payload(&output.stdout) {
+        if let Some(resolved) = resolve_exiftool_payload(&file.date_tags, &file.evidence) {
+            out.insert(PathBuf::from(file.source_file), resolved);
+        }
     }
     out
 }
 
-/// One row per input file. exiftool emits any tag we asked for that was
-/// present, plus the `SourceFile` it was reading. Tags are JSON values
-/// because `-d %s` returns the timestamp as a *string* of digits, not a
-/// number, when the date parses; absent tags are simply missing keys.
-#[derive(Debug, Deserialize)]
-struct ExiftoolEntry {
-    #[serde(rename = "SourceFile")]
-    source_file: String,
-    #[serde(rename = "DateTimeOriginal")]
-    date_time_original: Option<serde_json::Value>,
-    #[serde(rename = "SubSecDateTimeOriginal")]
-    sub_sec_date_time_original: Option<serde_json::Value>,
-    #[serde(rename = "CreateDate")]
-    create_date: Option<serde_json::Value>,
-    #[serde(rename = "MediaCreateDate")]
-    media_create_date: Option<serde_json::Value>,
-    #[serde(rename = "TrackCreateDate")]
-    track_create_date: Option<serde_json::Value>,
-    #[serde(rename = "ContentCreateDate")]
-    content_create_date: Option<serde_json::Value>,
+/// One raw date string from the exiftool payload, with the exiftool group
+/// it came from (`-G1` prefixes every tag key as `"Group:Tag"`).
+#[derive(Debug, Clone)]
+struct RawDateTag {
+    group: String,
+    tag: String,
+    value: String,
 }
 
-fn parse_exiftool_json(stdout: &[u8]) -> Vec<(String, i64)> {
-    let entries: Vec<ExiftoolEntry> = match serde_json::from_slice(stdout) {
+/// Per-file offset/GPS evidence from the same exiftool payload.
+#[derive(Copy, Clone, Debug, Default)]
+struct ExiftoolEvidence {
+    /// `OffsetTime` / `OffsetTimeDigitized`, whichever was present first.
+    offset_time: Option<i32>,
+    /// `OffsetTimeOriginal`.
+    offset_time_original: Option<i32>,
+    /// Unsigned decimal degrees; the Ref fields carry the sign.
+    gps_lat: Option<f64>,
+    gps_lon: Option<f64>,
+    gps_lat_south: bool,
+    gps_lon_west: bool,
+}
+
+impl ExiftoolEvidence {
+    /// Signed `(latitude, longitude)`, when both coordinates are present.
+    fn gps(self) -> Option<(f64, f64)> {
+        let lat = self.gps_lat?;
+        let lon = self.gps_lon?;
+        Some((
+            if self.gps_lat_south { -lat } else { lat },
+            if self.gps_lon_west { -lon } else { lon },
+        ))
+    }
+}
+
+/// How one raw date string should be interpreted.
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum DateReading {
+    /// The string carried its own UTC offset (zoned) — already a true
+    /// instant.
+    Zoned(i64),
+    /// Naive wall-clock reading; needs group classification and (for
+    /// photo-EXIF groups) the offset cascade.
+    Naive(NaiveDateTime),
+}
+
+/// Parse one exiftool date string. `None` for empty values, the
+/// `"0000:00:00 00:00:00"` zero placeholder exiftool emits for
+/// missing-but-allocated date slots, and anything before 1900.
+///
+/// Zoned strings (a trailing `Z`/`z` or a `±HH:MM[:SS]` offset) are true
+/// instants — XMP dates, some MakerNotes, and exiftool's own
+/// `Composite:SubSec*` rendering when an `OffsetTime*` tag is present —
+/// and are converted to unix seconds directly. Naive strings are returned
+/// as-is for group classification + the offset cascade.
+fn parse_exiftool_date_string(value: &str) -> Option<DateReading> {
+    let v = value.trim();
+    if v.is_empty() {
+        return None;
+    }
+    // Zoned form: split off the trailing offset, parse the naive part, and
+    // fold the offset into a true instant.
+    if let Some((naive_part, offset_minutes)) = split_zoned_suffix(v) {
+        let naive = parse_naive_exiftool(naive_part)?;
+        if naive.year() < 1900 {
+            return None;
+        }
+        let instant = naive.and_utc().timestamp() - (offset_minutes as i64) * 60;
+        return Some(DateReading::Zoned(instant));
+    }
+    let naive = parse_naive_exiftool(v)?;
+    if naive.year() < 1900 {
+        return None;
+    }
+    Some(DateReading::Naive(naive))
+}
+
+/// The naive date-time formats exiftool renders, in preference order. EXIF
+/// uses `:` between date fields; ISO uses `-`. The time separator is ` ` or
+/// `T`; fractional seconds are optional.
+const NAIVE_EXIFTOOL_FORMATS: &[&str] = &[
+    "%Y:%m:%d %H:%M:%S%.f",
+    "%Y-%m-%d %H:%M:%S%.f",
+    "%Y-%m-%dT%H:%M:%S%.f",
+    "%Y:%m:%d %H:%M:%S",
+    "%Y-%m-%d %H:%M:%S",
+    "%Y-%m-%dT%H:%M:%S",
+];
+
+/// Parse a naive (offset-less) exiftool date string.
+fn parse_naive_exiftool(v: &str) -> Option<NaiveDateTime> {
+    for fmt in NAIVE_EXIFTOOL_FORMATS {
+        if let Ok(naive) = NaiveDateTime::parse_from_str(v, fmt) {
+            return Some(naive);
+        }
+    }
+    None
+}
+
+/// Split a zoned date string into its naive part and its UTC offset in
+/// signed minutes (local − UTC). Recognises a trailing `Z`/`z` (UTC) or a
+/// `±HH:MM[:SS]` offset. The date's own `-` separators are skipped because
+/// only a `±` followed by a well-formed offset (digits and an optional
+/// `:SS` tail) is accepted.
+fn split_zoned_suffix(v: &str) -> Option<(&str, i32)> {
+    let b = v.as_bytes();
+    // Trailing Z / z → UTC.
+    if matches!(b.last(), Some(b'Z') | Some(b'z')) {
+        return Some((&v[..v.len() - 1], 0));
+    }
+    for (i, &c) in b.iter().enumerate() {
+        if (c == b'+' || c == b'-')
+            && i + 3 <= v.len()
+            && b[i + 1].is_ascii_digit()
+            && b[i + 2].is_ascii_digit()
+        {
+            let rest = v[i + 3..].strip_prefix(':').unwrap_or(&v[i + 3..]);
+            if rest.is_empty() || (rest.len() <= 2 && rest.bytes().all(|x| x.is_ascii_digit())) {
+                let sign = if c == b'+' { 1i32 } else { -1 };
+                let hh: i32 = v[i + 1..i + 3].parse().ok()?;
+                let mm: i32 = if rest.is_empty() {
+                    0
+                } else {
+                    rest.parse().ok()?
+                };
+                return Some((&v[..i], sign * (hh * 60 + mm)));
+            }
+        }
+    }
+    None
+}
+
+/// Parse an exiftool `OffsetTime*` rendering (`"+05:30"`, `"-06:00"`,
+/// `"Z"`) into signed minutes (local − UTC).
+fn parse_offset_minutes(value: &str) -> Option<i32> {
+    let v = value.trim();
+    if v == "Z" {
+        return Some(0);
+    }
+    let (sign, rest) = if let Some(r) = v.strip_prefix('-') {
+        (-1i32, r)
+    } else if let Some(r) = v.strip_prefix('+') {
+        (1, r)
+    } else {
+        return None;
+    };
+    let (h, m) = rest.split_once(':')?;
+    let h: i32 = h.trim().parse().ok()?;
+    let m: i32 = m.trim().parse().ok()?;
+    Some(sign * (h * 60 + m))
+}
+
+/// Parse exiftool's DMS GPS rendering, e.g. `"40 deg 42' 36.00\""`, into
+/// unsigned decimal degrees. The Ref field carries the sign.
+fn parse_gps_dms(value: &str) -> Option<f64> {
+    let v = value.trim();
+    let deg_end = v.find(" deg")?;
+    let deg: f64 = v[..deg_end].trim().parse().ok()?;
+    let rest = &v[deg_end + " deg".len()..];
+    let min_end = rest.find('\'')?;
+    let min: f64 = rest[..min_end].trim().parse().ok()?;
+    let rest = &rest[min_end + 1..];
+    let sec_end = rest.find('"')?;
+    let sec: f64 = rest[..sec_end].trim().parse().ok()?;
+    Some(deg + min / 60.0 + sec / 3600.0)
+}
+
+/// QuickTime/MP4/MOV container groups. The `creation_time` field in those
+/// containers is seconds-since-1904 in **UTC** — a true instant — and
+/// exiftool renders it as a UTC-naive string. Classifying these as camera
+/// wall clocks (running the cascade) reinterprets a UTC instant in the
+/// server zone and shifts every video by the server's UTC offset — the
+/// "videos off by 4-5 hours" bug, ticket #115.
+fn is_container_group(group: &str) -> bool {
+    group == "QuickTime" || group.starts_with("Track") || group == "Apple"
+}
+
+/// When the same tag name is present in multiple groups (hybrid files),
+/// prefer the photo-EXIF groups over container / XMP renderings.
+fn group_rank(group: &str) -> u8 {
+    if group.starts_with("ExifIFD")
+        || group == "IFD0"
+        || group == "IFD1"
+        || group.starts_with("MakerNote")
+        || group.starts_with("IFD")
+    {
+        0
+    } else if group == "Composite" {
+        1
+    } else if is_container_group(group) {
+        2
+    } else if group.starts_with("XMP") {
+        3
+    } else {
+        4
+    }
+}
+
+/// The legacy column's convention for a naive wall reading: interpret it
+/// in the *server's* local zone — exactly what exiftool `-d %s` did before
+/// this rework (verified: it ignores the file's own `OffsetTime*` tags).
+/// DST-aware: ambiguous fall-back walls take the earlier reading;
+/// nonexistent spring-forward walls take the earliest local interpretation
+/// — within an hour of what the old host produced.
+fn legacy_server_local(wall: NaiveDateTime) -> i64 {
+    match Local.from_local_datetime(&wall) {
+        LocalResult::Single(dt) => dt.timestamp(),
+        LocalResult::Ambiguous(earlier, _) => earlier.timestamp(),
+        // Nonexistent spring-forward wall: interpret the reading as UTC
+        // and take the zone's offset at that instant — within an hour of
+        // what the old exiftool/glibc path produced.
+        LocalResult::None => Local.from_utc_datetime(&wall).timestamp(),
+    }
+}
+
+/// Interpret one file's raw exiftool payload into a [`ResolvedDate`]
+/// under the new contract (ADR-0001):
+///
+/// - **zoned** strings carry their own UTC offset → true instant,
+///   `utc_direct`.
+/// - **container-group** naive strings are UTC-rendered `creation_time`
+///   fields → true instant, `utc_direct` (no cascade — see
+///   [`is_container_group`]).
+/// - **photo-EXIF / other** naive strings are camera wall clocks → offset
+///   cascade over the file's own `OffsetTime*` + GPS evidence.
+///
+/// Tag priority is [`EXIFTOOL_DATE_TAGS`]; within a tag name the photo
+/// group wins ([`group_rank`]). Unparseable candidates (zero dates,
+/// junk) fall through to the next candidate.
+fn resolve_exiftool_payload(
+    date_tags: &[RawDateTag],
+    evidence: &ExiftoolEvidence,
+) -> Option<ResolvedDate> {
+    let mut candidates: Vec<&RawDateTag> = date_tags.iter().collect();
+    candidates.sort_by(|a, b| {
+        let pa = EXIFTOOL_DATE_TAGS
+            .iter()
+            .position(|t| *t == a.tag)
+            .unwrap_or(usize::MAX);
+        let pb = EXIFTOOL_DATE_TAGS
+            .iter()
+            .position(|t| *t == b.tag)
+            .unwrap_or(usize::MAX);
+        pa.cmp(&pb)
+            .then_with(|| group_rank(&a.group).cmp(&group_rank(&b.group)))
+    });
+
+    for cand in candidates {
+        let Some(reading) = parse_exiftool_date_string(&cand.value) else {
+            continue;
+        };
+        match reading {
+            DateReading::Zoned(ts) => {
+                return Some(ResolvedDate {
+                    timestamp: ts,
+                    source: DateSource::Exiftool,
+                    date_utc: Some(ts),
+                    camera_offset_minutes: None,
+                    tz_source: Some(camera_tz::TzSource::UtcDirect),
+                });
+            }
+            DateReading::Naive(wall) => {
+                if is_container_group(&cand.group) {
+                    return Some(ResolvedDate {
+                        timestamp: legacy_server_local(wall),
+                        source: DateSource::Exiftool,
+                        date_utc: Some(wall.and_utc().timestamp()),
+                        camera_offset_minutes: None,
+                        tz_source: Some(camera_tz::TzSource::UtcDirect),
+                    });
+                }
+                // Camera wall clock: offset-tag pairing mirrors the
+                // kamadak branch (exif.rs) — DateTimeOriginal / SubSec*
+                // pair with OffsetTimeOriginal first, everything else with
+                // OffsetTime first.
+                let prefer_original =
+                    cand.tag == "DateTimeOriginal" || cand.tag == "SubSecDateTimeOriginal";
+                let offset_tag = if prefer_original {
+                    evidence.offset_time_original.or(evidence.offset_time)
+                } else {
+                    evidence.offset_time.or(evidence.offset_time_original)
+                };
+                let ev = camera_tz::OffsetEvidence {
+                    offset_tag_minutes: offset_tag,
+                    gps: evidence.gps(),
+                };
+                let resolution =
+                    camera_tz::resolve_camera_offset(wall, &ev, server_zone_cached(), gps_lookup());
+                return Some(ResolvedDate {
+                    timestamp: legacy_server_local(wall),
+                    source: DateSource::Exiftool,
+                    date_utc: Some(camera_tz::wall_to_instant(wall, resolution.minutes)),
+                    camera_offset_minutes: Some(resolution.minutes),
+                    tz_source: Some(resolution.source),
+                });
+            }
+        }
+    }
+    None
+}
+
+/// One file's share of the exiftool JSON payload.
+#[derive(Debug)]
+struct ExiftoolFileData {
+    source_file: String,
+    date_tags: Vec<RawDateTag>,
+    evidence: ExiftoolEvidence,
+}
+
+/// Split the exiftool `-j -G1` output into per-file date tags + evidence.
+/// With `-G1` every tag key is `"Group:Tag"` (only `SourceFile` is
+/// unprefixed); absent tags are simply missing keys.
+fn parse_exiftool_payload(stdout: &[u8]) -> Vec<ExiftoolFileData> {
+    let entries: Vec<serde_json::Value> = match serde_json::from_slice(stdout) {
         Ok(v) => v,
         Err(e) => {
             // Empty stdout on total failure isn't a parse error worth
@@ -447,103 +748,264 @@ fn parse_exiftool_json(stdout: &[u8]) -> Vec<(String, i64)> {
 
     let mut out = Vec::with_capacity(entries.len());
     for entry in entries {
-        // Walk the priority list. exiftool sometimes returns the literal
-        // string "0000:00:00 00:00:00" for missing-but-allocated date
-        // slots; with `-d %s` that becomes the unix epoch (0). Reject
-        // anything <= 0 so we fall through to the next tag.
-        let tags = [
-            entry.date_time_original.as_ref(),
-            entry.sub_sec_date_time_original.as_ref(),
-            entry.create_date.as_ref(),
-            entry.media_create_date.as_ref(),
-            entry.track_create_date.as_ref(),
-            entry.content_create_date.as_ref(),
-        ];
-        let mut chosen: Option<i64> = None;
-        for tag in tags.iter().flatten() {
-            if let Some(ts) = coerce_to_unix_seconds(tag)
-                && ts > 0
-            {
-                chosen = Some(ts);
-                break;
+        let Some(obj) = entry.as_object() else {
+            continue;
+        };
+        let Some(source_file) = obj.get("SourceFile").and_then(|v| v.as_str()) else {
+            continue;
+        };
+        let mut data = ExiftoolFileData {
+            source_file: source_file.to_string(),
+            date_tags: Vec::new(),
+            evidence: ExiftoolEvidence::default(),
+        };
+        for (key, value) in obj {
+            let Some((group, tag)) = key.split_once(':') else {
+                continue;
+            };
+            let Some(v) = value.as_str() else {
+                continue;
+            };
+            if EXIFTOOL_DATE_TAGS.contains(&tag) {
+                data.date_tags.push(RawDateTag {
+                    group: group.to_string(),
+                    tag: tag.to_string(),
+                    value: v.to_string(),
+                });
+            } else {
+                match tag {
+                    "OffsetTime" | "OffsetTimeDigitized" => {
+                        data.evidence.offset_time = data
+                            .evidence
+                            .offset_time
+                            .or_else(|| parse_offset_minutes(v));
+                    }
+                    "OffsetTimeOriginal" => {
+                        data.evidence.offset_time_original = parse_offset_minutes(v);
+                    }
+                    "GPSLatitude" => data.evidence.gps_lat = parse_gps_dms(v),
+                    "GPSLatitudeRef" => {
+                        data.evidence.gps_lat_south = v.trim().eq_ignore_ascii_case("S")
+                    }
+                    "GPSLongitude" => data.evidence.gps_lon = parse_gps_dms(v),
+                    "GPSLongitudeRef" => {
+                        data.evidence.gps_lon_west = v.trim().eq_ignore_ascii_case("W")
+                    }
+                    _ => {}
+                }
             }
         }
-        if let Some(ts) = chosen {
-            out.push((entry.source_file, ts));
-        }
+        out.push(data);
     }
     out
 }
 
-/// `-d %s` should hand us a numeric string, but exiftool's JSON encoder
-/// will emit a number when the tag was defined as numeric in its lib —
-/// accept both shapes.
-fn coerce_to_unix_seconds(v: &serde_json::Value) -> Option<i64> {
-    match v {
-        serde_json::Value::String(s) => s.trim().parse::<i64>().ok(),
-        serde_json::Value::Number(n) => n.as_i64(),
-        _ => None,
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
 
-    #[test]
-    fn parse_exiftool_json_picks_first_priority_tag() {
-        let json = br#"[{
-            "SourceFile": "/lib/IMG.jpg",
-            "DateTimeOriginal": "1500000000",
-            "CreateDate": "1400000000"
-        }]"#;
-        let parsed = parse_exiftool_json(json);
-        assert_eq!(parsed, vec![("/lib/IMG.jpg".to_string(), 1500000000)]);
+    fn tags(pairs: &[(&str, &str, &str)]) -> Vec<RawDateTag> {
+        pairs
+            .iter()
+            .map(|(g, t, v)| RawDateTag {
+                group: g.to_string(),
+                tag: t.to_string(),
+                value: v.to_string(),
+            })
+            .collect()
     }
 
     #[test]
-    fn parse_exiftool_json_falls_through_zeros() {
-        // exiftool emits "0000:00:00 00:00:00" → unix epoch 0 with -d %s.
-        // The resolver should skip those and pick the next tag.
-        let json = br#"[{
-            "SourceFile": "/lib/clip.mov",
-            "DateTimeOriginal": "0",
-            "MediaCreateDate": "1500000000"
-        }]"#;
-        let parsed = parse_exiftool_json(json);
-        assert_eq!(parsed, vec![("/lib/clip.mov".to_string(), 1500000000)]);
+    fn parse_date_string_zoned_forms_are_true_instants() {
+        // exiftool's Composite:SubSecDateTimeOriginal rendering when an
+        // OffsetTime tag is present: EXIF date separator, zoned time.
+        assert_eq!(
+            parse_exiftool_date_string("2024:09:17 07:33:59.414-06:00"),
+            Some(DateReading::Zoned(1_726_580_039)), // 13:33:59Z
+        );
+        assert_eq!(
+            parse_exiftool_date_string("2024-09-17T07:33:59Z"),
+            Some(DateReading::Zoned(1_726_558_439)), // 07:33:59Z
+        );
     }
 
     #[test]
-    fn parse_exiftool_json_accepts_numeric_values() {
+    fn parse_date_string_naive_and_rejects() {
+        assert_eq!(
+            parse_exiftool_date_string("2024:09:17 07:33:59"),
+            Some(DateReading::Naive(
+                NaiveDateTime::parse_from_str("2024-09-17 07:33:59", "%Y-%m-%d %H:%M:%S").unwrap()
+            )),
+        );
+        // Zero placeholder, empty, junk, pre-1900.
+        assert_eq!(parse_exiftool_date_string("0000:00:00 00:00:00"), None);
+        assert_eq!(parse_exiftool_date_string(""), None);
+        assert_eq!(parse_exiftool_date_string("nonsense"), None);
+        assert_eq!(parse_exiftool_date_string("1899:12:31 23:59:59"), None);
+    }
+
+    #[test]
+    fn parse_offset_minutes_forms() {
+        assert_eq!(parse_offset_minutes("+05:30"), Some(330));
+        assert_eq!(parse_offset_minutes("-06:00"), Some(-360));
+        assert_eq!(parse_offset_minutes("Z"), Some(0));
+        assert_eq!(parse_offset_minutes("junk"), None);
+    }
+
+    #[test]
+    fn parse_gps_dms_decimal() {
+        // 40 deg 42' 45.60" = 40.712666...; the Ref fields carry the sign.
+        let v = parse_gps_dms("40 deg 42' 45.60\"").unwrap();
+        assert!((v - 40.7126666667).abs() < 1e-9);
+        assert_eq!(parse_gps_dms("nope"), None);
+    }
+
+    #[test]
+    fn parse_payload_groups_dates_and_evidence() {
         let json = br#"[{
             "SourceFile": "/lib/a.jpg",
-            "CreateDate": 1234567890
+            "ExifIFD:DateTimeOriginal": "2024:07:04 12:00:00",
+            "ExifIFD:OffsetTimeOriginal": "-04:00",
+            "GPS:GPSLatitude": "40 deg 42' 45.60\"",
+            "GPS:GPSLatitudeRef": "N",
+            "GPS:GPSLongitude": "74 deg 0' 21.60\"",
+            "GPS:GPSLongitudeRef": "W"
         }]"#;
-        let parsed = parse_exiftool_json(json);
-        assert_eq!(parsed, vec![("/lib/a.jpg".to_string(), 1234567890)]);
+        let files = parse_exiftool_payload(json);
+        assert_eq!(files.len(), 1);
+        assert_eq!(files[0].source_file, "/lib/a.jpg");
+        assert_eq!(files[0].date_tags.len(), 1);
+        assert_eq!(files[0].date_tags[0].group, "ExifIFD");
+        assert_eq!(files[0].date_tags[0].tag, "DateTimeOriginal");
+        assert_eq!(files[0].evidence.offset_time_original, Some(-240));
+        let (lat, lon) = files[0].evidence.gps().unwrap();
+        assert!((lat - 40.7126666667).abs() < 1e-9);
+        assert!((lon - (-74.006)).abs() < 1e-9);
     }
 
     #[test]
-    fn parse_exiftool_json_emits_nothing_when_no_tag_present() {
-        let json = br#"[{"SourceFile": "/lib/no_dates.bin"}]"#;
-        let parsed = parse_exiftool_json(json);
-        assert!(parsed.is_empty());
+    fn container_date_is_true_instant_not_wall_clock() {
+        // QuickTime creation_time renders as a UTC-naive string: the
+        // 15:58:23 reading IS the instant. The pre-rework `-d %s` path
+        // reinterpreted it in the server zone — the "videos off by 4-5
+        // hours" bug — and the legacy column keeps exactly that (frozen
+        // for rollback).
+        let wall =
+            NaiveDateTime::parse_from_str("2017-06-11 15:58:23", "%Y-%m-%d %H:%M:%S").unwrap();
+        let resolved = resolve_exiftool_payload(
+            &tags(&[("QuickTime", "CreateDate", "2017:06:11 15:58:23")]),
+            &ExiftoolEvidence::default(),
+        )
+        .unwrap();
+        assert_eq!(resolved.date_utc, Some(wall.and_utc().timestamp()));
+        assert_eq!(resolved.tz_source, Some(camera_tz::TzSource::UtcDirect));
+        assert_eq!(resolved.camera_offset_minutes, None);
+        assert_eq!(resolved.timestamp, legacy_server_local(wall));
+        assert_eq!(resolved.source, DateSource::Exiftool);
     }
 
     #[test]
-    fn parse_exiftool_json_handles_multiple_entries() {
-        let json = br#"[
-            {"SourceFile": "/lib/a.jpg", "DateTimeOriginal": "100"},
-            {"SourceFile": "/lib/b.jpg", "CreateDate": "200"}
-        ]"#;
-        let parsed = parse_exiftool_json(json);
-        assert_eq!(
-            parsed,
-            vec![
-                ("/lib/a.jpg".to_string(), 100),
-                ("/lib/b.jpg".to_string(), 200)
-            ]
+    fn photo_and_video_at_same_instant_agree() {
+        // Photo: EXIF wall 2024-07-04 12:00:00 with an OffsetTime tag of
+        // -04:00. Video: QuickTime container date 2024:07:04 16:00:00 —
+        // the same moment, UTC-rendered. Both must land on 16:00:00Z.
+        let photo = resolve_exiftool_payload(
+            &tags(&[("ExifIFD", "DateTimeOriginal", "2024:07:04 12:00:00")]),
+            &ExiftoolEvidence {
+                offset_time_original: Some(-240),
+                ..Default::default()
+            },
+        )
+        .unwrap();
+        let video = resolve_exiftool_payload(
+            &tags(&[("QuickTime", "CreateDate", "2024:07:04 16:00:00")]),
+            &ExiftoolEvidence::default(),
+        )
+        .unwrap();
+        assert_eq!(photo.date_utc, video.date_utc);
+        assert_eq!(photo.date_utc, Some(1_720_108_800));
+        assert_eq!(photo.tz_source, Some(camera_tz::TzSource::OffsetTag));
+        assert_eq!(photo.camera_offset_minutes, Some(-240));
+        assert_eq!(video.tz_source, Some(camera_tz::TzSource::UtcDirect));
+    }
+
+    #[test]
+    fn zoned_string_short_circuits_to_utc_direct() {
+        let resolved = resolve_exiftool_payload(
+            &tags(&[("XMP-xmp", "CreateDate", "2024-09-17T07:33:59-06:00")]),
+            &ExiftoolEvidence::default(),
+        )
+        .unwrap();
+        assert_eq!(resolved.date_utc, Some(1_726_580_039));
+        assert_eq!(resolved.tz_source, Some(camera_tz::TzSource::UtcDirect));
+        assert_eq!(resolved.camera_offset_minutes, None);
+    }
+
+    #[test]
+    fn exif_naive_with_gps_uses_capture_zone() {
+        // No offset tag; GPS at Manhattan → America/New_York, EDT in July.
+        let resolved = resolve_exiftool_payload(
+            &tags(&[("ExifIFD", "CreateDate", "2024:07:04 12:00:00")]),
+            &ExiftoolEvidence {
+                gps_lat: Some(40.7128),
+                gps_lon: Some(74.006),
+                gps_lon_west: true,
+                ..Default::default()
+            },
+        )
+        .unwrap();
+        assert_eq!(resolved.tz_source, Some(camera_tz::TzSource::Gps));
+        assert_eq!(resolved.camera_offset_minutes, Some(-240));
+        assert_eq!(resolved.date_utc, Some(1_720_108_800));
+    }
+
+    #[test]
+    fn zero_date_falls_through_to_next_tag() {
+        // exiftool emits "0000:00:00 00:00:00" for missing-but-allocated
+        // date slots (iPhone QuickTime files); the resolver skips it and
+        // picks the next candidate.
+        let wall =
+            NaiveDateTime::parse_from_str("2020-01-02 03:04:05", "%Y-%m-%d %H:%M:%S").unwrap();
+        let resolved = resolve_exiftool_payload(
+            &tags(&[
+                ("QuickTime", "CreateDate", "0000:00:00 00:00:00"),
+                ("QuickTime", "MediaCreateDate", "2020:01:02 03:04:05"),
+            ]),
+            &ExiftoolEvidence::default(),
+        )
+        .unwrap();
+        assert_eq!(resolved.date_utc, Some(wall.and_utc().timestamp()));
+    }
+
+    #[test]
+    fn photo_group_wins_over_container_for_same_tag() {
+        // Hybrid file: ExifIFD and QuickTime both carry CreateDate. The
+        // photo-EXIF reading (a wall clock) is preferred and runs the
+        // cascade over the file's own offset tag.
+        let resolved = resolve_exiftool_payload(
+            &tags(&[
+                ("QuickTime", "CreateDate", "2024:07:04 16:00:00"),
+                ("ExifIFD", "CreateDate", "2024:07:04 12:00:00"),
+            ]),
+            &ExiftoolEvidence {
+                offset_time: Some(-240),
+                ..Default::default()
+            },
+        )
+        .unwrap();
+        assert_eq!(resolved.tz_source, Some(camera_tz::TzSource::OffsetTag));
+        assert_eq!(resolved.camera_offset_minutes, Some(-240));
+        assert_eq!(resolved.date_utc, Some(1_720_108_800));
+    }
+
+    #[test]
+    fn no_usable_dates_returns_none() {
+        assert!(
+            resolve_exiftool_payload(
+                &tags(&[("QuickTime", "CreateDate", "0000:00:00 00:00:00")]),
+                &ExiftoolEvidence::default()
+            )
+            .is_none()
         );
     }
 

src/files.rs

@@ -1519,6 +1519,9 @@ mod tests {
             date_utc: None,
             camera_offset_minutes: None,
             date_taken_tz_source: None,
+            original_date_utc: None,
+            original_camera_offset_minutes: None,
+            original_date_taken_tz_source: None,
         }
     }
 
@@ -1563,6 +1566,9 @@ mod tests {
                 date_utc: data.date_utc,
                 camera_offset_minutes: data.camera_offset_minutes,
                 date_taken_tz_source: data.date_taken_tz_source.clone(),
+                original_date_utc: data.date_utc,
+                original_camera_offset_minutes: data.camera_offset_minutes,
+                original_date_taken_tz_source: data.date_taken_tz_source.clone(),
             })
         }
 
@@ -1614,6 +1620,9 @@ mod tests {
                 date_utc: data.date_utc,
                 camera_offset_minutes: data.camera_offset_minutes,
                 date_taken_tz_source: data.date_taken_tz_source.clone(),
+                original_date_utc: data.date_utc,
+                original_camera_offset_minutes: data.camera_offset_minutes,
+                original_date_taken_tz_source: data.date_taken_tz_source.clone(),
             })
         }
 
@@ -1751,6 +1760,7 @@ mod tests {
             library_id: i32,
             rel_path: &str,
             date_taken: i64,
+            _display_tz: &str,
         ) -> Result<crate::database::models::ImageExif, DbError> {
             // Mock — files.rs tests don't exercise the date-override endpoints.
             // Returning a synthetic row keeps the trait satisfied without

src/handlers/image.rs

@@ -826,10 +826,14 @@ pub async fn get_full_exif(
     }
 }
 
-/// Body for `POST /image/exif/date` — operator-driven date_taken override.
-/// `date_taken` is unix seconds (matches `image_exif.date_taken`'s convention
-/// — naive local reinterpreted as UTC, not real UTC; the Apollo client passes
-/// through the same value the photo carousel rendered before edit).
+/// Body for `POST /image/exif/date` — operator-driven date override.
+/// `date_taken` is unix seconds: the wall the user picked rendered in their
+/// display zone, encoded naive-as-UTC (the Apollo client passes through the
+/// same value the photo carousel rendered before edit). The legacy
+/// `date_taken` column stores it verbatim; the new-contract triple
+/// (`date_utc` / `camera_offset_minutes` / `date_taken_tz_source =
+/// 'manual'`, ADR-0001 ticket #115) is derived from it as a wall clock in
+/// the user's display zone.
 #[derive(serde::Deserialize)]
 struct SetDateRequest {
     path: String,
@@ -910,9 +914,29 @@ pub async fn set_image_date(
     // doesn't end up with a backslash variant that misses the row.
     let normalized_path = body.path.replace('\\', "/");
 
+    // The user's display zone — the wall the UI sent is rendered in this
+    // zone (ADR-0001, ticket #115). NULL / unparseable prefs fall back to
+    // the app default inside display_zone_for.
+    let display_tz = {
+        let mut prefs_dao = app_state
+            .user_ai_prefs_dao
+            .lock()
+            .expect("Unable to lock UserAiPrefsDao");
+        match prefs_dao.get_prefs(&span_context) {
+            Ok(Some(prefs)) => crate::camera_tz::display_zone_for(prefs.display_tz.as_deref()),
+            _ => crate::camera_tz::display_zone_for(None),
+        }
+    };
+
     let updated = {
         let mut dao = exif_dao.lock().expect("Unable to lock ExifDao");
-        dao.set_manual_date_taken(&span_context, library.id, &normalized_path, body.date_taken)
+        dao.set_manual_date_taken(
+            &span_context,
+            library.id,
+            &normalized_path,
+            body.date_taken,
+            &display_tz,
+        )
     };
 
     match updated {