diff --git a/crates/engine/src/analysis/warp.rs b/crates/engine/src/analysis/warp.rs
index 0ab576d2c..b88d9df38 100644
--- a/crates/engine/src/analysis/warp.rs
+++ b/crates/engine/src/analysis/warp.rs
@@ -17,7 +17,7 @@ use std::sync::{Arc, Mutex};
 
 use effectcraft_effects::warp_stab::{self, ANALYSIS, ANALYSIS_KEY};
 use effectcraft_keyframe::Value;
-use effectcraft_project::{GroupKind, ItemId, ItemKind, Layer, LayerId, LayerSource, Project, PropGroup, Uid};
+use effectcraft_project::{Footage, GroupKind, ItemId, ItemKind, Layer, LayerId, LayerSource, Project, PropGroup, Uid};
 use effectcraft_raster::Image;
 use effectcraft_render::{EvalCtx, ExprHost, FootageSource, LayerCache, Renderer};
 use effectcraft_time::Tick;
@@ -112,7 +112,7 @@ fn fnv(s: &str) -> u64 {
 pub fn signature(p: &Project, comp: ItemId, layer: &Layer) -> String {
     let src = match &layer.source {
         LayerSource::Footage { item } | LayerSource::Solid { item } | LayerSource::Comp { item } => match p.item(*item).map(|i| &i.kind) {
-            Some(ItemKind::Footage(f)) => format!("{f:?}"),
+            Some(ItemKind::Footage(f)) => footage_text(f, true),
             Some(ItemKind::Solid(s)) => format!("{s:?}"),
             Some(ItemKind::Comp(c)) => format!("{}x{}@{:?}/{:?}", c.width, c.height, c.frame_rate, c.duration),
             _ => String::new(),
@@ -127,9 +127,96 @@ pub fn signature(p: &Project, comp: ItemId, layer: &Layer) -> String {
 pub(crate) fn signature_before_placed_page(p: &Project, comp: ItemId, layer: &Layer) -> Option<String> {
     let LayerSource::Footage { item } = &layer.source else { return None };
     let ItemKind::Footage(footage) = &p.item(*item)?.kind else { return None };
-    let src = format!("{footage:?}");
-    let old = src.strip_suffix(", placed_page: false }")?;
-    Some(signature_with_source(p, comp, layer, &format!("{old} }}")))
+    if footage.placed_page {
+        return None;
+    }
+    Some(signature_with_source(p, comp, layer, &footage_text(footage, false)))
+}
+
+/// A footage item in a signature: its fields as `Debug` wrote them in 0.23, the text saved
+/// analysis keys were hashed from (without `placed_page` before 0.23). It is written out here so
+/// that a new `Footage` field doesn't change every signature and drop every saved analysis.
+pub(crate) fn footage_text(f: &Footage, placed_page: bool) -> String {
+    format!("{:?}", FootageText { f, placed_page })
+}
+
+struct FootageText<'a> {
+    f: &'a Footage,
+    placed_page: bool,
+}
+
+impl std::fmt::Debug for FootageText<'_> {
+    fn fmt(&self, out: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        // Every field is named, so a new one doesn't compile until it is decided here. A new field
+        // that changes the frames goes last, written only when it isn't its default, so keys saved
+        // before it still match. A new field that doesn't change the frames stays out.
+        let Footage {
+            path,
+            kind,
+            width,
+            height,
+            pixel_aspect,
+            frame_rate,
+            native_rate,
+            duration,
+            has_video,
+            has_audio,
+            alpha,
+            premul_color,
+            loop_count,
+            codec,
+            missing,
+            sequence,
+            color_profile,
+            layer,
+            fields,
+            invert_alpha,
+            linear_light,
+            preserve_rgb,
+            cineon,
+            data,
+            page,
+            alphabetical,
+            start_timecode,
+            file_timecode,
+            markers,
+            placed_page,
+        } = self.f;
+        let mut d = out.debug_struct("Footage");
+        d.field("path", path)
+            .field("kind", kind)
+            .field("width", width)
+            .field("height", height)
+            .field("pixel_aspect", pixel_aspect)
+            .field("frame_rate", frame_rate)
+            .field("native_rate", native_rate)
+            .field("duration", duration)
+            .field("has_video", has_video)
+            .field("has_audio", has_audio)
+            .field("alpha", alpha)
+            .field("premul_color", premul_color)
+            .field("loop_count", loop_count)
+            .field("codec", codec)
+            .field("missing", missing)
+            .field("sequence", sequence)
+            .field("color_profile", color_profile)
+            .field("layer", layer)
+            .field("fields", fields)
+            .field("invert_alpha", invert_alpha)
+            .field("linear_light", linear_light)
+            .field("preserve_rgb", preserve_rgb)
+            .field("cineon", cineon)
+            .field("data", data)
+            .field("page", page)
+            .field("alphabetical", alphabetical)
+            .field("start_timecode", start_timecode)
+            .field("file_timecode", file_timecode)
+            .field("markers", markers);
+        if self.placed_page {
+            d.field("placed_page", placed_page);
+        }
+        d.finish()
+    }
 }
 
 fn signature_with_source(p: &Project, comp: ItemId, layer: &Layer, src: &str) -> String {
diff --git a/crates/engine/src/tests.rs b/crates/engine/src/tests.rs
index 19953053e..8d33ee3d4 100644
--- a/crates/engine/src/tests.rs
+++ b/crates/engine/src/tests.rs
@@ -27,6 +27,7 @@ mod key_metadata_order;
 mod key_time;
 mod keyframe_text;
 mod keylight;
+mod legacy_analysis_keys;
 mod limits;
 mod lottie;
 mod m137;
diff --git a/crates/engine/src/tests/legacy_analysis_keys.rs b/crates/engine/src/tests/legacy_analysis_keys.rs
new file mode 100644
index 000000000..f4e442050
--- /dev/null
+++ b/crates/engine/src/tests/legacy_analysis_keys.rs
@@ -0,0 +1,22 @@
+//! Warp Stabilizer and 3D Camera Tracker analyses saved by an earlier release keep matching
+//! their footage after an edit that doesn't change it (#3456), and a real change still clears them.
+
+/// The footage text analysis keys are hashed from, as 0.23 saved it. A new `Footage` field must
+/// not change it (or every saved analysis is dropped again).
+#[test]
+fn footage_signature_text_is_pinned() {
+    use effectcraft_project::{Footage, FootageKind};
+    let f = Footage {
+        path: "clip.mp4".into(),
+        kind: FootageKind::Video,
+        width: 160,
+        height: 120,
+        invert_alpha: true,
+        page: 2,
+        placed_page: true,
+        ..Footage::default()
+    };
+    let fields = r#"path: "clip.mp4", kind: Video, width: 160, height: 120, pixel_aspect: 1.0, frame_rate: FrameRate { num: 30, den: 1 }, native_rate: None, duration: Tick(0), has_video: false, has_audio: false, alpha: Straight, premul_color: [0.0, 0.0, 0.0], loop_count: 1, codec: "", missing: false, sequence: [], color_profile: None, layer: None, fields: Off, invert_alpha: true, linear_light: false, preserve_rgb: false, cineon: CineonSettings { log_conversion: false, converted_black: 0.0, converted_white: 1023.0, black: 95.0, white: 685.0, gamma: 1.7, rolloff: 20.0, units: TenBit }, data: None, page: 2, alphabetical: false, start_timecode: None, file_timecode: None, markers: []"#;
+    assert_eq!(crate::warp::footage_text(&f, true), format!("Footage {{ {fields}, placed_page: true }}"));
+    assert_eq!(crate::warp::footage_text(&f, false), format!("Footage {{ {fields} }}"));
+}