Cache audio waveforms and rescue oversized GIF previews

CURRENT.md

@@ -40,6 +40,12 @@ mobile draft at 390px.
   - [x] C11 preview caching: Discord-hosted image/GIF previews (WebP 320px, hash-addressed, 5 MiB
     cap, one attempt) run after every walk in both modes. Live run `...-20260916090722`:
     `previewed: 2`; thumbs served over `/api/media/<scrape>/<item>/thumb` (200).
+  - [x] C30 Preview completeness. Audio attachments and voice messages get an ffmpeg waveform
+    strip; oversized animated GIFs fall back to an ffmpeg-read first frame instead of `too large`;
+    transient network failures stay pending for the next backfill instead of becoming permanent.
+    Live: a scrape with 58 audio items backfilled 13 waveforms in 40 s, serving `image/webp`.
+    Remaining non-cached: Lottie stickers/custom emoji (not indexed as media) and embeds whose
+    pages refuse bots (marked PRIVATE/GONE by their 403/404).
   - [x] C29 Attachment video previews. Discord's image proxy renders a frame for video files
     (`?width=320&height=320&format=webp`), so `previewUrlFor` now resizes attachment mp4/webm in
     links mode too and `pendingPreviews` includes non-embed videos. Live: paused-scrape videos

docs/media-scraper.md

@@ -130,7 +130,12 @@ Previews run after every walk:
   10 s timeout, one attempt).
 - Animated GIF previews are stored as a static first frame (`ffmpeg`, 480px WebP); the original
   animated GIF URL stays in `preview_url` for hover playback. Tenor embeds without a thumbnail are
-  resolved through Tenor's oEmbed.
+  resolved through Tenor's oEmbed. An animated GIF over the size cap is framed by ffmpeg reading
+  the stream directly, so it is not lost to `too large`.
+- Audio attachments and voice messages get a waveform strip
+  (`ffmpeg -filter_complex showwavespic`) as their preview, rendered by ffmpeg from the URL.
+- Transient network failures are left pending for the next backfill pass; only skips (4xx, too
+  large, no source) are marked permanent.
 - One attempt per row, no retries; a failure marks `preview_error` and never fails the scrape.
 - Stored by hash in `thumbs/<sha256>.<ext>`, where the extension follows the response type
   (`preview_ext`, default webp); `preview_hash` and `preview_bytes` land on the row, and the

docs/media.md

@@ -91,8 +91,9 @@ media-scrape/db/
 - Third-party embeds are **never downloaded as media**: YouTube, Instagram, X, TikTok, and every
   other embed stays a link. Its thumbnail is cached (below); the video itself is never fetched.
 - Previews are cached in `thumbs/` after every walk, in both modes: Discord-hosted images, GIFs,
-  and video files (the proxy renders a frame, resized to 320px WebP) plus third-party embed
-  thumbnails (YouTube, X, TikTok, and so on). The
+  and video files (the proxy renders a frame, resized to 320px WebP), third-party embed thumbnails
+  (YouTube, X, TikTok, and so on), and audio, which gets a waveform strip so audio tiles are not
+  blank. The
   stored bytes keep their real type (`preview_ext`), so JPEG provider thumbnails are served as
   `image/jpeg`, not mislabeled WebP. Embeds without a thumbnail in Discord's data are resolved
   through the provider's oEmbed/fxtwitter API and finally the page's `og:image`. Previews count

media-scrape/src/download.ts

@@ -319,6 +319,43 @@ export async function videoPoster(
     }
 }
 
+/**
+ * A poster frame fetched by ffmpeg itself, without downloading the whole file through us.
+ * Handles oversized animated GIFs (first frame only) and audio (waveform strip).
+ */
+export async function remoteFrame(
+    url: string,
+    outDir: string,
+    options: { waveform?: boolean; ffmpeg?: string } = {}
+): Promise<{ hash: string; bytes: number } | null> {
+    const ffmpeg = options.ffmpeg ?? process.env.VESKSLOP_FFMPEG ?? "ffmpeg";
+    const temp = join(outDir, `.remote-${Date.now()}-${Math.random().toString(16).slice(2)}.webp`);
+    const filters = options.waveform
+        ? ["-filter_complex", "showwavespic=s=480x120:colors=white"]
+        : ["-frames:v", "1", "-vf", "scale=480:-1"];
+
+    try {
+        await execFileAsync(ffmpeg, ["-v", "error", "-y", "-i", url, ...filters, temp], {
+            timeout: 60_000
+        });
+
+        const buffer = readFileSync(temp);
+        if (!buffer.length) return null;
+
+        const hash = createHash("sha256").update(buffer).digest("hex");
+        renameSync(temp, join(outDir, `${hash}.webp`));
+        return { hash, bytes: buffer.length };
+    } catch {
+        return null;
+    } finally {
+        try {
+            rmSync(temp, { force: true });
+        } catch {
+            // already renamed
+        }
+    }
+}
+
 /** Static first-frame WebP from an animated GIF. Null when ffmpeg is missing or fails. */
 export async function gifPoster(
     inputPath: string,

media-scrape/src/engine.ts

@@ -12,6 +12,7 @@ import {
     gifPoster,
     previewGapMs,
     probeDimensions,
+    remoteFrame,
     videoPoster,
     type DownloadOptions
 } from "./download.js";
@@ -387,6 +388,24 @@ export class ScrapeEngine {
                 return;
             }
 
+            // Audio has no image proxy: render a waveform strip with ffmpeg.
+            if (row.kind === "audio" && row.source !== "embed") {
+                const waveform = await remoteFrame(row.url, join(dir, "thumbs"), { waveform: true });
+                if (waveform) {
+                    store.markPreview(row.id, {
+                        hash: waveform.hash,
+                        bytes: waveform.bytes,
+                        ext: "webp"
+                    });
+                    meta.previewed = (meta.previewed ?? 0) + 1;
+                } else {
+                    store.markPreviewError(row.id, "waveform failed");
+                }
+                this.persist(dir, meta);
+                await this.sleep(previewGapMs(options));
+                continue;
+            }
+
             // Some providers (fxtwitter, vxReddit, ...) ship no thumbnail in Discord's data;
             // resolve one from the provider or the page before caching it.
             let previewRow = row;
@@ -429,6 +448,22 @@ export class ScrapeEngine {
                     mkdirSync(dirname(target), { recursive: true });
                     copyFileSync(join(dir, "thumbs", `${hash}.${ext}`), target);
                 }
+            } else if (
+                outcome.state === "skipped" &&
+                outcome.error === "too large" &&
+                /\.gif(\?|$)/i.test(previewRow.preview_url ?? previewRow.url)
+            ) {
+                // Oversized animated GIF: let ffmpeg read the stream and keep one frame.
+                const frame = await remoteFrame(previewRow.preview_url ?? previewRow.url, join(dir, "thumbs"));
+                if (frame) {
+                    store.markPreview(row.id, { hash: frame.hash, bytes: frame.bytes, ext: "webp" });
+                    meta.previewed = (meta.previewed ?? 0) + 1;
+                } else {
+                    store.markPreviewError(row.id, "too large");
+                }
+            } else if (outcome.state === "failed") {
+                // Transient network failure: leave the row pending for the next pass.
+                this.log(`${meta.id}: preview ${row.id} failed: ${outcome.error ?? "unknown"}`);
             } else {
                 store.markPreviewError(row.id, outcome.error ?? outcome.state);
             }

media-scrape/src/store.ts

@@ -343,7 +343,7 @@ export class ScrapeStore {
      */
     pendingPreviews(limit = 5000, includeEmbeds = false): MediaRow[] {
         const local =
-            "((source IS NULL OR source != 'embed') AND kind IN ('image', 'gif', 'video'))";
+            "((source IS NULL OR source != 'embed') AND kind IN ('image', 'gif', 'video', 'audio'))";
         const condition = includeEmbeds
             ? `(${local} OR (source = 'embed' AND preview_url IS NOT NULL))`
             : local;

media-scrape/test/run.ts

@@ -9,7 +9,14 @@ import { createHash } from "node:crypto";
 import { existsSync, mkdirSync, mkdtempSync, rmSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
-import { downloadOne, downloadPreview, gifPoster, previewUrlFor, videoPoster } from "../src/download.js";
+import {
+    downloadOne,
+    downloadPreview,
+    gifPoster,
+    previewUrlFor,
+    remoteFrame,
+    videoPoster
+} from "../src/download.js";
 import { ogImageFromHtml, resolveEmbedPreview } from "../src/embed-preview.js";
 import { ScrapeEngine, type FetchPage, type ScrapeBackend } from "../src/engine.js";
 import { extractMedia } from "../src/extract.js";
@@ -954,6 +961,33 @@ void (async () => {
         );
     });
 
+    await test("remoteFrame renders an audio waveform", async () => {
+        const dir = join(root, "waveform-test");
+        mkdirSync(dir, { recursive: true });
+        const wavPath = join(dir, "tone.wav");
+
+        try {
+            execFileSync("ffmpeg", [
+                "-v",
+                "error",
+                "-y",
+                "-f",
+                "lavfi",
+                "-i",
+                "sine=frequency=440:duration=1",
+                wavPath
+            ]);
+        } catch {
+            console.log("ok - remoteFrame skipped (no ffmpeg)");
+            return;
+        }
+
+        const frame = await remoteFrame(wavPath, dir, { waveform: true });
+        assert.ok(frame?.hash);
+        assert.ok((frame?.bytes ?? 0) > 0);
+        assert.equal(existsSync(join(dir, `${frame?.hash}.webp`)), true);
+    });
+
     await test("snowflake helpers round-trip dates", () => {
         const id = snowflakeFromIso("2026-09-16T00:00:00.000Z");
         assert.ok(id);