Cache audio waveforms and rescue oversized GIF previews

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);
             }