test(engine): deferred counts match extraction on a B-frame NTSC source; VFR is not deferred

packages/engine/src/services/videoFrameExtractor.remoteTail.test.ts

@@ -92,3 +92,60 @@ describe.skipIf(!HAS_FFMPEG)("deferred windows of a remote source", { timeout: 1
     expect(peak).toBeGreaterThan(Math.max(1, Math.floor(cpus().length / 2)));
   });
 });
+
+describe.skipIf(!HAS_FFMPEG)("a deferred window inside local sources of other shapes", { timeout: 120_000 }, () => {
+  let dir: string;
+  beforeAll(() => {
+    dir = mkdtempSync(join(tmpdir(), "hf-defer-shapes-"));
+    const make = (name: string, args: string[]) => {
+      const made = spawnSync(getFfmpegBinary(), ["-v", "error", "-y", ...args, join(dir, name)]);
+      expect(made.status).toBe(0);
+    };
+    const source = ["-f", "lavfi", "-i", "testsrc2=size=160x90:rate=30000/1001:duration=12"];
+    make("ntsc-bframes.mp4", [...source, ...["-c:v", "libx264", "-bf", "3", "-g", "48"]]);
+    make("vfr.mp4", [
+      ...source,
+      ...["-vf", "select=not(mod(n\\,3))+not(mod(n\\,7))", "-fps_mode", "vfr", "-c:v", "libx264"],
+    ]);
+  });
+  afterAll(() => rmSync(dir, { recursive: true, force: true }));
+
+  const window = (src: string, mediaStart: number): VideoElement => ({
+    id: `w-${mediaStart}`,
+    src,
+    start: 0,
+    end: 3,
+    mediaStart,
+    loop: false,
+    hasAudio: false,
+  });
+
+  it.each([
+    { fps: 24, mediaStart: 1.37 },
+    { fps: 30, mediaStart: 0 },
+    { fps: 60, mediaStart: 4.2 },
+  ])("counts $fps fps frames of an NTSC source with B-frames as extracting them does", async (c) => {
+    const options = { fps: c.fps, outputDir: join(dir, `out-${c.fps}-${c.mediaStart}`) };
+    const full = await extractAllVideoFrames([window("ntsc-bframes.mp4", c.mediaStart)], dir, options);
+    const deferred = await extractAllVideoFrames(
+      [window("ntsc-bframes.mp4", c.mediaStart)],
+      dir,
+      { ...options, outputDir: join(dir, `defer-${c.fps}-${c.mediaStart}`), deferRangeExtraction: true },
+    );
+
+    expect(deferred.extracted[0]?.deferredRange).toBeDefined();
+    expect(deferred.extracted[0]?.totalFrames).toBe(full.extracted[0]?.totalFrames);
+  });
+
+  it("leaves a variable-frame-rate source to a full extraction", async () => {
+    const deferred = await extractAllVideoFrames([window("vfr.mp4", 1)], dir, {
+      fps: 30,
+      outputDir: join(dir, "defer-vfr"),
+      deferRangeExtraction: true,
+    });
+
+    expect(deferred.errors).toEqual([]);
+    expect(deferred.extracted[0]?.deferredRange).toBeUndefined();
+    expect(deferred.extracted[0]?.framePaths.size).toBeGreaterThan(0);
+  });
+});