fix(connector): build shots at the shot's frame rate, not a hardcoded 24

Shot.fps existed, the lookup API returned it, and one button honoured it
— Set Start Timecode — while the shot builder ignored it entirely. Comps
were created at 24 and every plate conformed to 24.

DH2 is a 25 fps show. Its plates carry framesPerSecond 25/1, so comps
built at 24 conform every plate to the wrong speed and compute every
frame-from-timecode sum against the wrong rate.

The builder now takes the rate from the shot record, which is the show's
delivery rate and therefore the authority; a plate's own rate is whatever
happens to be on disk. Import Renders follows the comp it imports into,
and Import EXR follows the shot.

Validation gains plate_fps, comparing the render against the timing
plate. timecode_fps only compares the render to its manifest and both
come from the comp, so a shot built at the wrong rate agrees with itself
and passes; the plate is the independent witness. It is a WARN, never a
FAIL: sampling DH2 found one plate at 50 fps against a 25 fps show, a
deliberate over-crank, so a whole-number multiple is reported as exactly
that and anything else as a probable rate mistake.

Note this does not fix the data: all 175 DH2 shots still carry fps 24
from the create-time default and need correcting before their comps are
rebuilt.

Panel 2.4.0, worker 1.4.0.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

RenderWorker/VFXReviewWorker.Tests/ValidationStageTests.cs

@@ -26,14 +26,14 @@ public class ValidationStageTests : IDisposable
     }
 
     /// <summary>Writes a sequence numbered from 1001 with a plate-derived timecode.</summary>
-    private void WriteSequence(int count, string startTimecode, int firstFrame = 1001)
+    private void WriteSequence(int count, string startTimecode, int firstFrame = 1001, int fps = 24)
     {
-        var start = Timecode.Parse(startTimecode)!.Value.ToFrames(24);
+        var start = Timecode.Parse(startTimecode)!.Value.ToFrames(fps);
         for (var i = 0; i < count; i++)
         {
-            var tc = Timecode.FromFrames(start + i, 24);
+            var tc = Timecode.FromFrames(start + i, fps);
             var path = Path.Combine(_dir, $"UNG_107_051_010_cmp_TT_v004.{firstFrame + i:D5}.exr");
-            File.Move(ExrFixture.Write(tc.ToString(), 3840, 2160, new[] { ("B", 1), ("G", 1), ("R", 1) }, 24, 4), path);
+            File.Move(ExrFixture.Write(tc.ToString(), 3840, 2160, new[] { ("B", 1), ("G", 1), ("R", 1) }, fps, 4), path);
         }
     }
 
@@ -109,6 +109,66 @@ public class ValidationStageTests : IDisposable
         Assert.Contains("8-frame handle", tc.Message);
     }
 
+    [Fact]
+    public void APlateAtADifferentRateFailsPlateFps()
+    {
+        // The DH2 case: a 25 fps show whose shot records defaulted to 24, so
+        // every comp was built at 24. The render agrees with its own manifest,
+        // so only the plate can reveal it.
+        WriteSequence(105, "14:26:31:08");
+        var plate = Path.Combine(_dir, "plate", "UNG_107_051_010_BG01_TT_v001.01001.exr");
+        Directory.CreateDirectory(Path.GetDirectoryName(plate)!);
+        File.Move(ExrFixture.Write("14:26:31:08", 3840, 2160, new[] { ("B", 1), ("G", 1), ("R", 1) }, 25, 4), plate);
+
+        var manifest = Manifest(_dir, "14:26:31:16", 1001);
+        manifest.Source = new ManifestSource { TimingPlate = new PlateRef { Path = plate, FrameStart = 1001 } };
+
+        var outcome = NewStage().Run(manifest, _dir, new ServerConfig());
+        var fpsCheck = Check(outcome, "plate_fps");
+        Assert.Equal("WARN", fpsCheck.Status);
+        Assert.Equal("25", fpsCheck.Expected);
+        Assert.Equal("24", fpsCheck.Actual);
+        Assert.Contains("wrong rate", fpsCheck.Message);
+
+        // timecode_fps alone would not have caught it: the render and the
+        // manifest agree with each other at 24.
+        Assert.Equal("PASS", Check(outcome, "timecode_fps").Status);
+    }
+
+    [Fact]
+    public void AnOverCrankedPlateIsRecognisedRatherThanReportedAsAMistake()
+    {
+        // A 50 fps plate on a 25 fps show is deliberate slow motion, conformed
+        // on purpose — real on DH2, and it must not read as a rate error.
+        WriteSequence(105, "14:26:31:08", fps: 25);
+        var plate = Path.Combine(_dir, "plate", "DH2_PL01.01001.exr");
+        Directory.CreateDirectory(Path.GetDirectoryName(plate)!);
+        File.Move(ExrFixture.Write("14:26:31:08", 3840, 2160, new[] { ("B", 1), ("G", 1), ("R", 1) }, 50, 4), plate);
+
+        var manifest = Manifest(_dir, null, 1001);
+        manifest.Fps = 25;
+        manifest.Source = new ManifestSource { TimingPlate = new PlateRef { Path = plate, FrameStart = 1001 } };
+
+        var check = Check(NewStage().Run(manifest, _dir, new ServerConfig()), "plate_fps");
+        Assert.Equal("WARN", check.Status);
+        Assert.Contains("over-crank", check.Message);
+        Assert.DoesNotContain("wrong rate", check.Message);
+    }
+
+    [Fact]
+    public void MatchingRatesPassPlateFps()
+    {
+        WriteSequence(105, "14:26:31:08");
+        var plate = Path.Combine(_dir, "plate", "UNG_107_051_010_BG01_TT_v001.01001.exr");
+        Directory.CreateDirectory(Path.GetDirectoryName(plate)!);
+        File.Move(ExrFixture.Write("14:26:31:08", 3840, 2160, new[] { ("B", 1), ("G", 1), ("R", 1) }, 24, 4), plate);
+
+        var manifest = Manifest(_dir, "14:26:31:16", 1001);
+        manifest.Source = new ManifestSource { TimingPlate = new PlateRef { Path = plate, FrameStart = 1001 } };
+
+        Assert.Equal("PASS", Check(NewStage().Run(manifest, _dir, new ServerConfig()), "plate_fps").Status);
+    }
+
     [Fact]
     public void GapsAreStillCaughtWithinTheRun()
     {

RenderWorker/VFXReviewWorker/VFXReviewWorker.csproj

@@ -15,7 +15,7 @@
       every change that gets published. publish.ps1 appends the git SHA via
       SourceRevisionId, giving "1.1.0+feb1c7b".
     -->
-    <Version>1.3.0</Version>
+    <Version>1.4.0</Version>
   </PropertyGroup>
 
   <ItemGroup>

RenderWorker/VFXReviewWorker/ValidationStage.cs

@@ -350,6 +350,31 @@ public sealed class ValidationStage
             return;
         }
 
+        // plate_fps — the render's rate against the plate's own.
+        //
+        // timecode_fps only compares the render to the manifest, and both come
+        // from the comp: a shot built at the wrong rate agrees with itself and
+        // passes. The plate is the independent witness. A 25 fps show whose
+        // shot records defaulted to 24 renders every shot at 24, and this is
+        // what names that rather than leaving it to surface as an off-by-N
+        // timecode error.
+        if (reference.PlateFps is double plateFps && first.H.FramesPerSecond is double renderFps)
+        {
+            var ratio = renderFps > 0 ? plateFps / renderFps : 0;
+            var overcrank = ratio > 1.5 && Math.Abs(ratio - Math.Round(ratio)) < 0.01;
+
+            checks.Add(Math.Abs(plateFps - renderFps) < 0.01
+                ? ValidationCheck.Pass("plate_fps", plateFps.ToString("0.###"), renderFps.ToString("0.###"))
+                // Never a FAIL: a plate deliberately shot at a multiple of the
+                // show rate is a legitimate over-crank, conformed on purpose.
+                // Anything else is a rate mistake, and the wording says which.
+                : ValidationCheck.Warn("plate_fps", plateFps.ToString("0.###"), renderFps.ToString("0.###"),
+                    overcrank
+                        ? $"The plate is {plateFps:0.###} fps against a {renderFps:0.###} fps render — a {Math.Round(ratio)}x over-crank, conformed as expected."
+                        : $"The plate is {plateFps:0.###} fps but this rendered at {renderFps:0.###} — not a whole-number over-crank, so the comp was probably built at the wrong rate (check the shot's fps in the database).",
+                    new { platePath = reference.PlatePath, reference = reference.Kind, ratio }));
+        }
+
         var expectedFrames = reference.PlateTimecode.ToFrames(fps) + (renderFirstFrame - reference.PlateFirstFrame);
         var expected = Timecode.FromFrames(expectedFrames, fps);
         var actualFrames = renderTc.ToFrames(fps);
@@ -415,7 +440,8 @@ public sealed class ValidationStage
                 var frame = SequencePattern.FrameFromName(Path.GetFileName(local))
                             ?? timing.FrameStart
                             ?? renderFirstFrame;
-                return new TimecodeReference("manifest", local, header.Timecode.Value, frame, handleFrames);
+                return new TimecodeReference("manifest", local, header.Timecode.Value, frame, handleFrames,
+                    header.FramesPerSecond);
             }
             _log.LogWarning("Timing plate from manifest is unreadable: {Path}", local);
         }
@@ -507,7 +533,7 @@ public sealed class ValidationStage
         if (header?.Timecode is null) return null;
 
         var frame = SequencePattern.FrameFromName(Path.GetFileName(firstFile)) ?? m.FrameStart;
-        return new TimecodeReference("derived", firstFile, header.Timecode.Value, frame, 0);
+        return new TimecodeReference("derived", firstFile, header.Timecode.Value, frame, 0, header.FramesPerSecond);
     }
 
     private static void AddCandidate(List<(string Dir, int Count)> candidates, string dir)
@@ -554,7 +580,8 @@ public sealed class ValidationStage
 }
 
 public sealed record TimecodeReference(
-    string Kind, string? PlatePath, Timecode PlateTimecode, int PlateFirstFrame, int HandleFrames);
+    string Kind, string? PlatePath, Timecode PlateTimecode, int PlateFirstFrame, int HandleFrames,
+    double? PlateFps = null);
 
 public sealed record ValidationOutcome(
     List<ValidationCheck> Checks, int FileCount, long TotalBytes, string? Checksum)