Ask ffmpeg for the frames the capturer actually wrote

lib/ads/gif/encode.ts

@@ -16,6 +16,7 @@ import { execFile } from "node:child_process";
 import { promisify } from "node:util";
 import path from "node:path";
 import { GIF_FPS } from "../video/profiles";
+import { FRAME_PATTERN } from "../video/render";
 
 const run = promisify(execFile);
 
@@ -71,7 +72,12 @@ export async function encodeGif(input: {
   ffmpegPath?: string;
 }): Promise<void> {
   const ffmpeg = input.ffmpegPath ?? "ffmpeg";
-  const pattern = path.join(input.frameDir, "frame-%04d.png");
+  // The shared pattern, not a second copy of it. These were written down twice
+  // and drifted: the capturer emits f-0000.png and this module asked ffmpeg for
+  // frame-0000.png, so every banner encode failed with "could find no file"
+  // while the frame count check passed — it counts .png files and never looks
+  // at their names.
+  const pattern = path.join(input.frameDir, FRAME_PATTERN);
   const palette = path.join(input.frameDir, "palette.png");
 
   await run(ffmpeg, paletteArgs(pattern, palette), { maxBuffer: 16 * 1024 * 1024 });

lib/ads/gif/render.ts

@@ -14,7 +14,7 @@ import { mkdir, readdir, stat } from "node:fs/promises";
 import path from "node:path";
 import { GIF_FRAMES, videoProfile, type GifProfileId } from "../video/profiles";
 import type { VideoDesignSnapshot } from "../video/snapshot";
-import type { FrameCapturer } from "../video/render";
+import { FRAME_PATTERN, type FrameCapturer } from "../video/render";
 import { GIF_UNITS, gifDocument } from "./compose";
 import { encodeGif, validateGif } from "./encode";
 
@@ -74,10 +74,19 @@ export async function renderAnimatedBanners(args: {
     // The compositor is the only thing that decides how many frames exist. If
     // the capture disagrees, the timeline did not run and encoding whatever
     // landed would ship a banner that is silently short.
-    const captured = (await readdir(framesDir)).filter((f) => f.endsWith(".png"));
-    if (captured.length !== GIF_FRAMES) {
+    //
+    // Checked by NAME, not just by count. Counting alone passed while the
+    // capturer wrote f-0000.png and the encoder asked ffmpeg for
+    // frame-0000.png, so the mismatch reached production as an ffmpeg error
+    // instead of a clear one here.
+    const wanted = Array.from({ length: GIF_FRAMES }, (_, i) =>
+      FRAME_PATTERN.replace("%04d", String(i).padStart(4, "0")),
+    );
+    const present = new Set(await readdir(framesDir));
+    const missing = wanted.filter((f) => !present.has(f));
+    if (missing.length > 0) {
       throw new Error(
-        `${unit.id}: captured ${captured.length} frames, expected ${GIF_FRAMES}`,
+        `${unit.id}: ${missing.length} of ${GIF_FRAMES} frames missing, first is ${missing[0]}`,
       );
     }
 

lib/ads/video/render.ts

@@ -388,11 +388,12 @@ export async function renderPreroll(args: {
         });
       }
     } catch (err) {
-      problems.push({
-        check: "animated banners",
-        expected: "three units",
-        actual: (err as Error).message,
-      });
+      // Deliberately NOT pushed onto `problems`: everything in there fails the
+      // revision, and this comment previously claimed a failed banner would not
+      // — while the code did the opposite and failed whole renders whose video
+      // was fine. The banners are optional profiles; their absence is visible
+      // in the asset list, and the reason belongs in the log.
+      console.warn(`[render] animated banners skipped: ${(err as Error).message}`);
     }
   }
 

tests/ads-gif-pipeline.test.ts

@@ -8,6 +8,7 @@ import { GIF_UNITS, gifDocument, gifFrameState, gifTimeline, GIF_TIMELINE } from
 import { GIF_PALETTE_COLORS, gifArgs, paletteArgs, validateGif } from "@/lib/ads/gif/encode";
 import { renderAnimatedBanners } from "@/lib/ads/gif/render";
 import { GIF_FPS, GIF_FRAMES, videoProfile } from "@/lib/ads/video/profiles";
+import { FRAME_PATTERN } from "@/lib/ads/video/render";
 import type { VideoDesignSnapshot } from "@/lib/ads/video/snapshot";
 
 const run = promisify(execFile);
@@ -189,7 +190,10 @@ describe("end to end through real ffmpeg", () => {
           const svgPath = path.join(a.outDir, `f-${i}.svg`);
           await writeFile(svgPath, svg, "utf8");
           await run("ffmpeg", ["-y", "-v", "error", "-i", svgPath,
-            path.join(a.outDir, `frame-${String(i).padStart(4, "0")}.png`)]);
+            // Named exactly as the real capturer names them, derived from the
+            // shared pattern. Writing "frame-%04d.png" here is what let the
+            // encoder's divergent literal pass CI and fail in production.
+            path.join(a.outDir, FRAME_PATTERN.replace("%04d", String(i).padStart(4, "0")))]);
           await rm(svgPath);
         }
       };